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Secure Remote Password protocol - Wikipedia

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class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Augmented password-authenticated key exchange protocol</div> <p>The <b>Secure Remote Password protocol</b> (<b>SRP</b>) is an augmented <a href="/wiki/Password-authenticated_key_agreement" title="Password-authenticated key agreement">password-authenticated key exchange</a> (PAKE) protocol, specifically designed to work around existing patents.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">&#91;</span>1<span class="cite-bracket">&#93;</span></a></sup> </p><p>Like all PAKE protocols, an eavesdropper or <a href="/wiki/Man-in-the-middle_attack" title="Man-in-the-middle attack">man in the middle</a> cannot obtain enough information to be able to <a href="/wiki/Brute-force_attack" title="Brute-force attack">brute-force guess</a> a password or apply a <a href="/wiki/Dictionary_attack" title="Dictionary attack">dictionary attack</a> without further interactions with the parties for each guess. Furthermore, being an augmented PAKE protocol, the server does not store password-equivalent data.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">&#91;</span>2<span class="cite-bracket">&#93;</span></a></sup> This means that an attacker who steals the server data cannot masquerade as the client unless they first perform a brute force search for the password. </p><p>In layman's terms, during SRP (or any other PAKE protocol) authentication, one party (the "client" or "user") demonstrates to another party (the "server") that they know the password, without sending the password itself nor any other information from which the password can be derived. The password never leaves the client and is unknown to the server. </p><p>Furthermore, the server also needs to know about the password (but not the password itself) in order to instigate the secure connection. This means that the server also authenticates itself to the client which prevents <a href="/wiki/Phishing" title="Phishing">phishing</a> without reliance on the user parsing complex URLs. </p><p>The only mathematically proven security property of SRP is that it is equivalent to Diffie-Hellman against a <i>passive</i> attacker.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">&#91;</span>3<span class="cite-bracket">&#93;</span></a></sup> Newer PAKEs such as AuCPace<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">&#91;</span>4<span class="cite-bracket">&#93;</span></a></sup> and OPAQUE offer stronger guarantees.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">&#91;</span>5<span class="cite-bracket">&#93;</span></a></sup> </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Overview">Overview</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_Remote_Password_protocol&amp;action=edit&amp;section=1" title="Edit section: Overview"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The SRP protocol has a number of desirable properties: it allows a user to authenticate themselves to a server, it is resistant to <a href="/wiki/Dictionary_attack" title="Dictionary attack">dictionary attacks</a> mounted by an eavesdropper, and it does not require a <a href="/wiki/Trusted_third_party" title="Trusted third party">trusted third party</a>. It effectively conveys a <a href="/wiki/Zero-knowledge_password_proof" title="Zero-knowledge password proof">zero-knowledge password proof</a> from the user to the server. In revision 6 of the protocol only one password can be guessed per connection attempt. One of the interesting properties of the protocol is that even if one or two of the cryptographic primitives it uses are attacked, it is still secure. The SRP protocol has been revised several times, and is currently at revision 6a. </p><p>The SRP protocol creates a large private key shared between the two parties in a manner similar to <a href="/wiki/Diffie%E2%80%93Hellman_key_exchange" title="Diffie–Hellman key exchange">Diffie–Hellman key exchange</a> based on the client side having the user password and the server side having a <a href="/wiki/Cryptography" title="Cryptography">cryptographic</a> verifier derived from the password. The shared public key is derived from two random numbers, one generated by the client, and the other generated by the server, which are unique to the login attempt. In cases where encrypted communications as well as authentication are required, the SRP protocol is more secure than the alternative <a href="/wiki/Secure_Shell" title="Secure Shell">SSH</a> protocol and faster than using <a href="/wiki/Diffie%E2%80%93Hellman_key_exchange" title="Diffie–Hellman key exchange">Diffie–Hellman key exchange</a> with signed messages. It is also independent of third parties, unlike <a href="/wiki/Kerberos_(protocol)" title="Kerberos (protocol)">Kerberos</a>. </p><p>The SRP protocol, version 3 is described in RFC 2945. SRP version 6a is also used for strong password authentication in <a href="/wiki/Transport_Layer_Security" title="Transport Layer Security">SSL/TLS</a><sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">&#91;</span>6<span class="cite-bracket">&#93;</span></a></sup> (in <a href="/wiki/TLS-SRP" title="TLS-SRP">TLS-SRP</a>) and other standards such as <a href="/wiki/Extensible_Authentication_Protocol" title="Extensible Authentication Protocol">EAP</a><sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">&#91;</span>7<span class="cite-bracket">&#93;</span></a></sup> and <a href="/wiki/Security_Assertion_Markup_Language" title="Security Assertion Markup Language">SAML</a>, and is part of <a href="/wiki/IEEE_P1363" title="IEEE P1363">IEEE 1363.2</a> and ISO/IEC 11770-4. </p> <div class="mw-heading mw-heading2"><h2 id="Protocol">Protocol</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_Remote_Password_protocol&amp;action=edit&amp;section=2" title="Edit section: Protocol"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The following notation is used in this description of the protocol, version 6: </p> <ul><li><i>q</i> and <i>N</i> = 2<i>q</i> + 1 are chosen such that both are prime (which makes <i>q</i> a <a href="/wiki/Sophie_Germain_prime" class="mw-redirect" title="Sophie Germain prime">Sophie Germain prime</a> and <i>N</i> a <a href="/wiki/Safe_prime" class="mw-redirect" title="Safe prime">safe prime</a>). <i>N</i> must be large enough so that computing discrete logarithms modulo <i>N</i> is infeasible.</li> <li>All arithmetic is performed in the <a href="/wiki/Ring_of_integers" title="Ring of integers">ring of integers</a> modulo <i>N</i>, <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \scriptstyle \mathbb {Z} _{N}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mstyle displaystyle="false" scriptlevel="1"> <msub> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="double-struck">Z</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mi>N</mi> </mrow> </msub> </mstyle> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \scriptstyle \mathbb {Z} _{N}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/bf35ef0285944e01c09509aaec613d08ea0230c7" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.445ex; height:2.009ex;" alt="{\displaystyle \scriptstyle \mathbb {Z} _{N}}"></span>. This means that below <i>g</i><sup><var style="padding-right: 1px;">x</var></sup> should be read as <i>g</i><sup><var style="padding-right: 1px;">x</var></sup><i>mod N</i></li> <li><i>g</i> is a <a href="/wiki/Multiplicative_group_of_integers_modulo_n" title="Multiplicative group of integers modulo n">generator of the multiplicative group <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \scriptstyle \mathbb {Z} _{N}^{*}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mstyle displaystyle="false" scriptlevel="1"> <msubsup> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="double-struck">Z</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mi>N</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mo>&#x2217;<!-- ∗ --></mo> </mrow> </msubsup> </mstyle> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \scriptstyle \mathbb {Z} _{N}^{*}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/0f4be728b59af693787c5860befd60b664208a35" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:2.445ex; height:2.343ex;" alt="{\displaystyle \scriptstyle \mathbb {Z} _{N}^{*}}"></span></a>.</li> <li><i>H</i>() is a <a href="/wiki/Cryptographic_hash_function" title="Cryptographic hash function">hash</a> function; e.g., SHA-256.</li> <li><i>k</i> is a parameter derived by both sides; in SRP-6, <i>k</i> = 3, while in SRP-6a it is derived from <i>N</i> and <i>g</i>&#160;: <i>k</i> = <i>H</i>(<i>N</i>, <i>g</i>). It is used to prevent a 2-for-1 guess when an active attacker impersonates the server.<sup id="cite_ref-srp6_8-0" class="reference"><a href="#cite_note-srp6-8"><span class="cite-bracket">&#91;</span>8<span class="cite-bracket">&#93;</span></a></sup><sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">&#91;</span>9<span class="cite-bracket">&#93;</span></a></sup></li> <li><i>s</i> is a <a href="/wiki/Salt_(cryptography)" title="Salt (cryptography)">salt</a>.</li> <li><span class="texhtml mvar" style="font-style:italic;">I</span> is an identifying username.</li> <li><i>p</i> is the user's password.</li> <li><i>v</i> is the host's password verifier, <i>v</i> = <i>g</i><sup><var style="padding-right: 1px;">x</var></sup> where at a minimum <i>x</i> = <i>H</i>(<i>s</i>, <i>p</i>). As <i>x</i> is only computed on the client it is free to choose a stronger algorithm. An implementation could choose to use <span class="texhtml"><i>x</i> = <i>H</i>(<i>s</i> | <i>I</i> | <i>p</i>)</span> without affecting any steps required of the host. The standard <a rel="nofollow" class="external text" href="https://tools.ietf.org/html/rfc2945">RFC2945</a> defines <span class="texhtml"><i>x</i> = <i>H</i>(<i>s</i> | <i>H</i> ( <i>I</i> | ":" | <i>p</i>) )</span>. Use of <span class="texhtml mvar" style="font-style:italic;">I</span> within <i>x</i> avoids a malicious server from being able to learn if <a rel="nofollow" class="external text" href="https://crypto.stackexchange.com/a/9430">two users share the same password</a>.</li> <li><i>A</i> and <i>B</i> are random one time ephemeral keys of the user and host respectively.</li> <li>| (pipe) denotes concatenation.</li></ul> <p>All other variables are defined in terms of these. </p><p>First, to establish a password <i>p</i> with server Steve, client Carol picks a random <a href="/wiki/Salt_(cryptography)" title="Salt (cryptography)">salt</a> <i>s</i>, and computes <i>x</i> = <i>H</i>(<i>s</i>, <i>p</i>), <i>v</i> = <i>g</i><sup><var style="padding-right: 1px;">x</var></sup>. Steve stores <i>v</i> and <i>s</i>, indexed by <span class="texhtml mvar" style="font-style:italic;">I</span>, as Carol's password verifier and salt. Carol must not share <i>x</i> with anybody, and must safely erase it at this step, because it is <a href="/wiki/Pass_the_hash" title="Pass the hash">equivalent</a> to the plaintext password <i>p</i>. This step is completed before the system is used as part of the user registration with Steve. Note that the salt <i>s</i> is shared and exchanged to negotiate a session key later so the value could be chosen by either side but is done by Carol so that she can register <span class="texhtml mvar" style="font-style:italic;">I</span>, <i>s</i> and <i>v</i> in a single registration request. The transmission and authentication of the registration request is not covered in SRP. </p><p>Then to perform a proof of password at a later date the following exchange protocol occurs: </p> <ol><li>Carol → Steve: generate random value <i>a</i>; send <span class="texhtml mvar" style="font-style:italic;">I</span> and <i>A</i> = <i>g</i><sup><var style="padding-right: 1px;">a</var></sup></li> <li>Steve → Carol: generate random value <i>b</i>; send <i>s</i> and <i>B</i> = <i>kv</i> + <i>g</i><sup><var style="padding-right: 1px;">b</var></sup></li> <li>Both: <i>u</i> = <i>H</i>(<i>A</i>, <i>B</i>)</li> <li>Carol: <i>S</i><sub>Carol</sub> = (<i>B</i> − <i>kg</i><sup><var style="padding-right: 1px;">x</var></sup>)<sup>(<i>a</i> + <i>ux</i>)</sup> = (<i>kv</i> + <i>g</i><sup><var style="padding-right: 1px;">b</var></sup> − <i>kg</i><sup><var style="padding-right: 1px;">x</var></sup>)<sup>(<i>a</i> + <i>ux</i>)</sup> = (<i>kg</i><sup><var style="padding-right: 1px;">x</var></sup> − <i>kg</i><sup><var style="padding-right: 1px;">x</var></sup> + <i>g</i><sup><var style="padding-right: 1px;">b</var></sup>)<sup>(a + ux)</sup> = (<i>g</i><sup><var style="padding-right: 1px;">b</var></sup>)<sup>(<i>a</i> + <i>ux</i>)</sup></li> <li>Carol: <i>K</i><sub>Carol</sub> = <i>H</i>(<i>S</i><sub>Carol</sub>)</li> <li>Steve: <i>S</i><sub>Steve</sub> = (<i>Av</i><sup><var style="padding-right: 1px;">u</var></sup>)<sup><var style="padding-right: 1px;">b</var></sup> = (<i>g</i><sup><var style="padding-right: 1px;">a</var></sup><i>v</i><sup><var style="padding-right: 1px;">u</var></sup>)<sup><var style="padding-right: 1px;">b</var></sup> = [<i>g</i><sup><var style="padding-right: 1px;">a</var></sup>(<i>g</i><sup><var style="padding-right: 1px;">x</var></sup>)<sup><var style="padding-right: 1px;">u</var></sup>]<sup><var style="padding-right: 1px;">b</var></sup> = (<i>g</i><sup>a + ux</sup>)<sup><var style="padding-right: 1px;">b</var></sup> = (<i>g</i><sup><var style="padding-right: 1px;">b</var></sup>)<sup>(a + ux)</sup></li> <li>Steve: <i>K</i><sub>Steve</sub> = <i>H</i>(<i>S</i><sub>Steve</sub>) = <i>K</i><sub>Carol</sub></li></ol> <p>Now the two parties have a shared, strong session key <i>K</i>. To complete authentication, they need to prove to each other that their keys match. One possible way is as follows: </p> <ol><li>Carol → Steve: <span class="texhtml"><i>M</i><sub>1</sub> = <i>H</i>[<i>H</i>(<i>N</i>) <a href="/wiki/XOR" class="mw-redirect" title="XOR">XOR</a> <i>H</i>(<i>g</i>) | <i>H</i>(<i>I</i>) | <i>s</i> | <i>A</i> | <i>B</i> | <i>K</i><sub>Carol</sub>]</span>. Steve verifies <i>M</i><sub>1</sub>.</li> <li>Steve → Carol: <span class="texhtml"><i>M</i><sub>2</sub> = <i>H</i>(<i>A</i> | <i>M</i><sub>1</sub> | <i>K</i><sub>Steve</sub>)</span>. Carol verifies <i>M</i><sub>2</sub>.</li></ol> <p>This method requires guessing more of the shared state to be successful in impersonation than just the key. While most of the additional state is public, private information could safely be added to the inputs to the hash function, like the server private key.<sup class="noprint Inline-Template" style="margin-left:0.1em; white-space:nowrap;">&#91;<i><a href="/wiki/Wikipedia:Please_clarify" title="Wikipedia:Please clarify"><span title="The text near this tag may need clarification or removal of jargon. (February 2014)">clarification needed</span></a></i>&#93;</sup> </p><p>Alternatively, in a password-only proof the calculation of <i>K</i> can be skipped and the shared <i>S</i> proven with: </p> <ol><li>Carol → Steve: <span class="texhtml"><i>M</i><sub>1</sub> = <i>H</i>(<i>A</i> | <i>B</i> | <i>S</i><sub>Carol</sub>)</span>. Steve verifies <i>M</i><sub>1</sub>.</li> <li>Steve → Carol: <span class="texhtml"><i>M</i><sub>2</sub> = <i>H</i>(<i>A</i> | <i>M</i><sub>1</sub> | <i>S</i><sub>Steve</sub>)</span>. Carol verifies <i>M</i><sub>2</sub>.</li></ol> <p>When using SRP to negotiate a shared key <i>K</i> which will be immediately used after the negotiation, it is tempting to skip the verification steps of <i>M</i><sub>1</sub> and <i>M</i><sub>2</sub>. The server will reject the very first request from the client which it cannot decrypt. This can however be dangerous as demonstrated in the Implementation Pitfalls section below. </p><p>The two parties also employ the following safeguards: </p> <ol><li>Carol will abort if she receives <i>B</i> = 0 (mod <i>N</i>) or <i>u</i> = 0.</li> <li>Steve will abort if he receives <i>A</i> (mod <i>N</i>) = 0.</li> <li>Carol must show her proof of <i>K</i> (or <i>S</i>) first. If Steve detects that Carol's proof is incorrect, he must abort without showing his own proof of <i>K</i> (or <i>S</i>)</li></ol> <div class="mw-heading mw-heading3"><h3 id="Example_code_in_Python">Example code in Python</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_Remote_Password_protocol&amp;action=edit&amp;section=3" title="Edit section: Example code in Python"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-highlight mw-highlight-lang-python mw-content-ltr" dir="ltr"><pre><span></span><span class="sd">&quot;&quot;&quot;</span> <span class="sd">An example SRP authentication</span> <span class="sd">WARNING: Do not use for real cryptographic purposes beyond testing.</span> <span class="sd">WARNING: This below code misses important safeguards. It does not check A, B, and U are not zero.</span> <span class="sd">based on http://srp.stanford.edu/design.html</span> <span class="sd">&quot;&quot;&quot;</span> <span class="kn">import</span> <span class="nn">hashlib</span> <span class="kn">import</span> <span class="nn">random</span> <span class="c1"># Note: str converts as is, str([1,2,3,4]) will convert to &quot;[1,2,3,4]&quot;</span> <span class="k">def</span> <span class="nf">H</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="nb">int</span><span class="p">:</span> <span class="w"> </span><span class="sd">&quot;&quot;&quot;A one-way hash function.&quot;&quot;&quot;</span> <span class="n">a</span> <span class="o">=</span> <span class="s2">&quot;:&quot;</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="nb">str</span><span class="p">(</span><span class="n">a</span><span class="p">)</span> <span class="k">for</span> <span class="n">a</span> <span class="ow">in</span> <span class="n">args</span><span class="p">)</span> <span class="k">return</span> <span class="nb">int</span><span class="p">(</span><span class="n">hashlib</span><span class="o">.</span><span class="n">sha256</span><span class="p">(</span><span class="n">a</span><span class="o">.</span><span class="n">encode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">))</span><span class="o">.</span><span class="n">hexdigest</span><span class="p">(),</span> <span class="mi">16</span><span class="p">)</span> <span class="k">def</span> <span class="nf">cryptrand</span><span class="p">(</span><span class="n">n</span><span class="p">:</span> <span class="nb">int</span> <span class="o">=</span> <span class="mi">1024</span><span class="p">):</span> <span class="k">return</span> <span class="n">random</span><span class="o">.</span><span class="n">SystemRandom</span><span class="p">()</span><span class="o">.</span><span class="n">getrandbits</span><span class="p">(</span><span class="n">n</span><span class="p">)</span> <span class="o">%</span> <span class="n">N</span> <span class="c1"># A large safe prime (N = 2q+1, where q is prime)</span> <span class="c1"># All arithmetic is done modulo N</span> <span class="c1"># (generated using &quot;openssl dhparam -text 1024&quot;)</span> <span class="n">N</span> <span class="o">=</span> <span class="s2">&quot;&quot;&quot;00:c0:37:c3:75:88:b4:32:98:87:e6:1c:2d:a3:32:</span> <span class="s2"> 4b:1b:a4:b8:1a:63:f9:74:8f:ed:2d:8a:41:0c:2f:</span> <span class="s2"> c2:1b:12:32:f0:d3:bf:a0:24:27:6c:fd:88:44:81:</span> <span class="s2"> 97:aa:e4:86:a6:3b:fc:a7:b8:bf:77:54:df:b3:27:</span> <span class="s2"> c7:20:1f:6f:d1:7f:d7:fd:74:15:8b:d3:1c:e7:72:</span> <span class="s2"> c9:f5:f8:ab:58:45:48:a9:9a:75:9b:5a:2c:05:32:</span> <span class="s2"> 16:2b:7b:62:18:e8:f1:42:bc:e2:c3:0d:77:84:68:</span> <span class="s2"> 9a:48:3e:09:5e:70:16:18:43:79:13:a8:c3:9c:3d:</span> <span class="s2"> d0:d4:ca:3c:50:0b:88:5f:e3&quot;&quot;&quot;</span> <span class="n">N</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">N</span><span class="o">.</span><span class="n">split</span><span class="p">())</span><span class="o">.</span><span class="n">replace</span><span class="p">(</span><span class="s2">&quot;:&quot;</span><span class="p">,</span> <span class="s2">&quot;&quot;</span><span class="p">),</span> <span class="mi">16</span><span class="p">)</span> <span class="n">g</span> <span class="o">=</span> <span class="mi">2</span> <span class="c1"># A generator modulo N</span> <span class="n">k</span> <span class="o">=</span> <span class="n">H</span><span class="p">(</span><span class="n">N</span><span class="p">,</span> <span class="n">g</span><span class="p">)</span> <span class="c1"># Multiplier parameter (k=3 in legacy SRP-6)</span> <span class="n">F</span> <span class="o">=</span> <span class="s1">&#39;#0x&#39;</span> <span class="c1"># Format specifier</span> <span class="nb">print</span><span class="p">(</span><span class="s2">&quot;#. H, N, g, and k are known beforehand to both client and server:&quot;</span><span class="p">)</span> <span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s1">&#39;</span><span class="si">{</span><span class="n">H</span><span class="w"> </span><span class="si">= }</span><span class="se">\n</span><span class="si">{</span><span class="n">N</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="se">\n</span><span class="si">{</span><span class="n">g</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="se">\n</span><span class="si">{</span><span class="n">k</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="s1">&#39;</span><span class="p">)</span> <span class="nb">print</span><span class="p">(</span><span class="s2">&quot;</span><span class="se">\n</span><span class="s2">0. server stores (I, s, v) in its password database&quot;</span><span class="p">)</span> <span class="c1"># The server must first generate the password verifier</span> <span class="n">I</span> <span class="o">=</span> <span class="s2">&quot;person&quot;</span> <span class="c1"># Username</span> <span class="n">p</span> <span class="o">=</span> <span class="s2">&quot;password1234&quot;</span> <span class="c1"># Password</span> <span class="n">s</span> <span class="o">=</span> <span class="n">cryptrand</span><span class="p">(</span><span class="mi">64</span><span class="p">)</span> <span class="c1"># Salt for the user</span> <span class="n">x</span> <span class="o">=</span> <span class="n">H</span><span class="p">(</span><span class="n">s</span><span class="p">,</span> <span class="n">I</span><span class="p">,</span> <span class="n">p</span><span class="p">)</span> <span class="c1"># Private key</span> <span class="n">v</span> <span class="o">=</span> <span class="nb">pow</span><span class="p">(</span><span class="n">g</span><span class="p">,</span> <span class="n">x</span><span class="p">,</span> <span class="n">N</span><span class="p">)</span> <span class="c1"># Password verifier</span> <span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s1">&#39;</span><span class="si">{</span><span class="n">I</span><span class="w"> </span><span class="si">= }</span><span class="se">\n</span><span class="si">{</span><span class="n">p</span><span class="w"> </span><span class="si">= }</span><span class="se">\n</span><span class="si">{</span><span class="n">s</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="se">\n</span><span class="si">{</span><span class="n">x</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="se">\n</span><span class="si">{</span><span class="n">v</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="s1">&#39;</span><span class="p">)</span> <span class="c1"># 0. server stores(I, s, v) in its password database</span> <span class="c1"># I = &#39;person&#39;</span> <span class="c1"># p = &#39;password1234&#39;</span> <span class="c1"># s = 0x67bc8932cfd26a49</span> <span class="c1"># x = 0x98a4bce8dde877762a90222f1a1161eba9248590a47eb83aa9e5bd7ecda5368d</span> <span class="c1"># v = 0xa7e2038e675d577ac0f318999cab67bba7ec2daf45d2d09f7911b1b78d2fc7f963cd0ac8f17851e0516f059e453672c3b70fcecf5f6843180b271abdd01f552ccda7b24fe4719336409cbc1352f8517be651b8935cc0b74ff2819fa07a3f031537d4cfd9f8df7b788a5f2f88e1cd4106b35c38b3d7205a</span> <span class="c1"># &lt;demo&gt; --- stop ---</span> <span class="nb">print</span><span class="p">(</span><span class="s2">&quot;</span><span class="se">\n</span><span class="s2">1. client sends username I and public ephemeral value A to the server&quot;</span><span class="p">)</span> <span class="n">a</span> <span class="o">=</span> <span class="n">cryptrand</span><span class="p">()</span> <span class="n">A</span> <span class="o">=</span> <span class="nb">pow</span><span class="p">(</span><span class="n">g</span><span class="p">,</span> <span class="n">a</span><span class="p">,</span> <span class="n">N</span><span class="p">)</span> <span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">I</span><span class="w"> </span><span class="si">= }</span><span class="se">\n</span><span class="si">{</span><span class="n">A</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="s2">&quot;</span><span class="p">)</span> <span class="c1"># client-&gt;server (I, A)</span> <span class="c1"># 1. client sends username I and public ephemeral value A to the server</span> <span class="c1"># I = &#39;person&#39;</span> <span class="c1"># A = 0x678556a7e76581e051af656e8cee57ae46df43f1fce790f7750a3ec5308a85da4ec4051e5cb74d3e463685ee975a2747cf49035be67c931b56e793f23ea3524af8909dcfbc8675d872361025bf884778587ac49454a57c53a011ac2be2839bfb51bf7847a49a483aba870dc7a8b467a81cec91b8ae7813</span> <span class="c1"># &lt;demo&gt; --- stop ---</span> <span class="nb">print</span><span class="p">(</span><span class="s2">&quot;</span><span class="se">\n</span><span class="s2">2. server sends user&#39;s salt s and public ephemeral value B to client&quot;</span><span class="p">)</span> <span class="n">b</span> <span class="o">=</span> <span class="n">cryptrand</span><span class="p">()</span> <span class="n">B</span> <span class="o">=</span> <span class="p">(</span><span class="n">k</span> <span class="o">*</span> <span class="n">v</span> <span class="o">+</span> <span class="nb">pow</span><span class="p">(</span><span class="n">g</span><span class="p">,</span> <span class="n">b</span><span class="p">,</span> <span class="n">N</span><span class="p">))</span> <span class="o">%</span> <span class="n">N</span> <span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">s</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="se">\n</span><span class="si">{</span><span class="n">B</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="s2">&quot;</span><span class="p">)</span> <span class="c1"># server-&gt;client (s, B)</span> <span class="c1"># 2. server sends user&#39;s salt s and public ephemeral value B to client</span> <span class="c1"># s = 0x67bc8932cfd26a49</span> <span class="c1"># B = 0xb615a0a5ea6abf138077bbd869f6a8da37dfc0b7e06a9f5fac5c1e4109c6302cb3e94dcc2cc76da7b3d87d7e9b68a1db998ab239cfde609f3f7a1ece4a491ce3d9a665c20cf4e4f06730daaa8f52ed61e45bbb67cdc337bf648027ffa7f0f215d5ebe43f9f51832518f1142266aae0dfa960e0082b5154</span> <span class="c1"># &lt;demo&gt; --- stop ---</span> <span class="nb">print</span><span class="p">(</span><span class="s2">&quot;</span><span class="se">\n</span><span class="s2">3. client and server calculate the random scrambling parameter&quot;</span><span class="p">)</span> <span class="n">u</span> <span class="o">=</span> <span class="n">H</span><span class="p">(</span><span class="n">A</span><span class="p">,</span> <span class="n">B</span><span class="p">)</span> <span class="c1"># Random scrambling parameter</span> <span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">u</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="s2">&quot;</span><span class="p">)</span> <span class="c1"># 3. client and server calculate the random scrambling parameter</span> <span class="c1"># u = 0x796b07e354c04f672af8b76a46560655086355a9bbce11361f01b45d991c0c52</span> <span class="c1"># &lt;demo&gt; --- stop ---</span> <span class="nb">print</span><span class="p">(</span><span class="s2">&quot;</span><span class="se">\n</span><span class="s2">4. client computes session key&quot;</span><span class="p">)</span> <span class="n">x</span> <span class="o">=</span> <span class="n">H</span><span class="p">(</span><span class="n">s</span><span class="p">,</span> <span class="n">I</span><span class="p">,</span> <span class="n">p</span><span class="p">)</span> <span class="n">S_c</span> <span class="o">=</span> <span class="nb">pow</span><span class="p">(</span><span class="n">B</span> <span class="o">-</span> <span class="n">k</span> <span class="o">*</span> <span class="nb">pow</span><span class="p">(</span><span class="n">g</span><span class="p">,</span> <span class="n">x</span><span class="p">,</span> <span class="n">N</span><span class="p">),</span> <span class="n">a</span> <span class="o">+</span> <span class="n">u</span> <span class="o">*</span> <span class="n">x</span><span class="p">,</span> <span class="n">N</span><span class="p">)</span> <span class="n">K_c</span> <span class="o">=</span> <span class="n">H</span><span class="p">(</span><span class="n">S_c</span><span class="p">)</span> <span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">S_c</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="se">\n</span><span class="si">{</span><span class="n">K_c</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="s2">&quot;</span><span class="p">)</span> <span class="c1"># 4. client computes session key</span> <span class="c1"># S_c = 0x699170aff6e9f08ed09a1dff432bf0605b8bcba05aadcaeea665757d06dbda4348e211d16c10ef4678585bcb2809a83c62b6c19d97901274ddafd4075f90604c06baf036af587af8540342b47867eaa22b9ca5e35ac14c8e85a0c4e623bd855828dffd513cea4d829c407137a0dd81ab4cde8a904c45cc</span> <span class="c1"># K_c = 0x43f8df6e1d2ba762948c8316db5bf03a7af49391742f5f51029630711c1671e</span> <span class="c1"># &lt;demo&gt; --- stop ---</span> <span class="nb">print</span><span class="p">(</span><span class="s2">&quot;</span><span class="se">\n</span><span class="s2">5. server computes session key&quot;</span><span class="p">)</span> <span class="n">S_s</span> <span class="o">=</span> <span class="nb">pow</span><span class="p">(</span><span class="n">A</span> <span class="o">*</span> <span class="nb">pow</span><span class="p">(</span><span class="n">v</span><span class="p">,</span> <span class="n">u</span><span class="p">,</span> <span class="n">N</span><span class="p">),</span> <span class="n">b</span><span class="p">,</span> <span class="n">N</span><span class="p">)</span> <span class="n">K_s</span> <span class="o">=</span> <span class="n">H</span><span class="p">(</span><span class="n">S_s</span><span class="p">)</span> <span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">S_s</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="se">\n</span><span class="si">{</span><span class="n">K_s</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="s2">&quot;</span><span class="p">)</span> <span class="c1"># 5. server computes session key</span> <span class="c1"># S_s = 0x699170aff6e9f08ed09a1dff432bf0605b8bcba05aadcaeea665757d06dbda4348e211d16c10ef4678585bcb2809a83c62b6c19d97901274ddafd4075f90604c06baf036af587af8540342b47867eaa22b9ca5e35ac14c8e85a0c4e623bd855828dffd513cea4d829c407137a0dd81ab4cde8a904c45cc</span> <span class="c1"># K_s = 0x43f8df6e1d2ba762948c8316db5bf03a7af49391742f5f51029630711c1671e</span> <span class="c1"># &lt;demo&gt; --- stop ---</span> <span class="nb">print</span><span class="p">(</span><span class="s2">&quot;</span><span class="se">\n</span><span class="s2">6. client sends proof of session key to server&quot;</span><span class="p">)</span> <span class="n">M_c</span> <span class="o">=</span> <span class="n">H</span><span class="p">(</span><span class="n">H</span><span class="p">(</span><span class="n">N</span><span class="p">)</span> <span class="o">^</span> <span class="n">H</span><span class="p">(</span><span class="n">g</span><span class="p">),</span> <span class="n">H</span><span class="p">(</span><span class="n">I</span><span class="p">),</span> <span class="n">s</span><span class="p">,</span> <span class="n">A</span><span class="p">,</span> <span class="n">B</span><span class="p">,</span> <span class="n">K_c</span><span class="p">)</span> <span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">M_c</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="s2">&quot;</span><span class="p">)</span> <span class="c1"># client-&gt;server (M_c)&#160;; server verifies M_c</span> <span class="c1"># 6. client sends proof of session key to server</span> <span class="c1"># M_c = 0x75500df4ea36e06406ac1f8a8241429b8e90a8cba3adda3405c07f19ea3101e8</span> <span class="c1"># &lt;demo&gt; --- stop ---</span> <span class="nb">print</span><span class="p">(</span><span class="s2">&quot;</span><span class="se">\n</span><span class="s2">7. server sends proof of session key to client&quot;</span><span class="p">)</span> <span class="n">M_s</span> <span class="o">=</span> <span class="n">H</span><span class="p">(</span><span class="n">A</span><span class="p">,</span> <span class="n">M_c</span><span class="p">,</span> <span class="n">K_s</span><span class="p">)</span> <span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">M_s</span><span class="w"> </span><span class="si">=&#160;:{</span><span class="n">F</span><span class="si">}}</span><span class="s2">&quot;</span><span class="p">)</span> <span class="c1"># server-&gt;client (M_s)&#160;; client verifies M_s</span> <span class="c1"># 7. server sends proof of session key to client</span> <span class="c1"># M_s = 0x182ed24d1ad2fb55d2268c46b42435d1ef02e0fc49f647c03dab8b2a48b0bd3d</span> </pre></div> <p><br /> </p> <div class="mw-heading mw-heading2"><h2 id="Implementation_pitfalls">Implementation pitfalls</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_Remote_Password_protocol&amp;action=edit&amp;section=4" title="Edit section: Implementation pitfalls"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Offline_bruteforce_attack_with_server-first_messaging_in_the_absence_of_key_verification">Offline bruteforce attack with server-first messaging in the absence of key verification</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_Remote_Password_protocol&amp;action=edit&amp;section=5" title="Edit section: Offline bruteforce attack with server-first messaging in the absence of key verification"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>If the server sends an encrypted message without waiting for verification from the client then an attacker is able to mount an offline bruteforce attack similar to hash cracking. This can happen if the server sends an encrypted message in the second packet alongside the salt and <i>B</i> or if key verification is skipped and the server (rather than the client) sends the first encrypted message. This is tempting as after the very first packet, the server has every information to compute the shared key <i>K</i>. </p><p>The attack goes as follow: </p> <ol><li>Carol → Steve: generate random value <i>a</i>; send <span class="texhtml mvar" style="font-style:italic;">I</span> and <i>A</i> = <i>g</i><sup><var style="padding-right: 1px;">a</var></sup></li> <li>Steve: <span class="texhtml"><i>u</i> = <i>H</i>(<i>A</i>, <i>B</i>); <i>S</i>=<i>Av</i><sup><var style="padding-right: 1px;">u</var></sup>; <i>K</i>=<i>H</i>(<i>S</i>)</span></li> <li>Steve: generate message <i>m</i> and encrypts it to produce <span class="texhtml"><i>c</i>=ENC(<i>K</i>,<i>m</i>)</span></li> <li>Steve → Carol: generate random value <i>b</i>; send <i>s</i>, <span class="texhtml"><i>B</i> = <i>kv</i> + <i>g</i><sup><var style="padding-right: 1px;">b</var></sup></span> and <i>c</i></li></ol> <p>Carol doesn't know <i>x</i> or <i>v</i>. But given any password <i>p</i> she can compute: </p> <ul><li><span class="texhtml"><i>x</i><sub><i>p</i></sub> = <i>H</i>(salt, <i>p</i>)</span></li> <li><span class="texhtml"><i>S</i><sub><i>p</i></sub> = (<i>B</i> - <i>kg</i><sup><i>x</i><sub><i>p</i></sub></sup>)<sup>(<i>a</i> + <i>ux</i><sub><i>p</i></sub>)</sup></span></li> <li><span class="texhtml"><i>K</i><sub>p</sub> = <i>H</i>(<i>S</i><sub>p</sub>)</span></li></ul> <p><i>K</i><sub><i>p</i></sub> is the key that Steve would use if <i>p</i> was the expected password. All values required to compute <i>K</i><sub><i>p</i></sub> are either controlled by Carol or known from the first packet from Steve. Carol can now try to guess the password, generate the corresponding key, and attempt to decrypt Steve's encrypted message <i>c</i> to verify the key. As protocol messages tend to be structured, it is assumed that identifying that <i>c</i> was properly decrypted is easy. This allows offline recovery of the password. </p><p>This attack would not be possible had Steve waited for Carol to prove she was able to compute the correct key before sending an encrypted message. Proper implementations of SRP are not affected by this attack as the attacker would be unable to pass the key verification step. </p> <div class="mw-heading mw-heading3"><h3 id="Offline_bruteforce_based_on_timing_attack">Offline bruteforce based on timing attack</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_Remote_Password_protocol&amp;action=edit&amp;section=6" title="Edit section: Offline bruteforce based on timing attack"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In 2021 Daniel De Almeida Braga, Pierre-Alain Fouque and Mohamed Sabt published PARASITE,<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">&#91;</span>10<span class="cite-bracket">&#93;</span></a></sup> a paper in which they demonstrate practical exploitation of a timing attack over the network. This exploits non-constant implementations of modular exponentiation of big numbers and impacted OpenSSL in particular. </p> <div class="mw-heading mw-heading2"><h2 id="Implementations">Implementations</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_Remote_Password_protocol&amp;action=edit&amp;section=7" title="Edit section: Implementations"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a rel="nofollow" class="external text" href="https://github.com/Glusk/srp6-variables">SRP-6 Variables</a> A Java library of cryptographic primitives required to implement the SRP-6 protocol.</li> <li><a href="/wiki/OpenSSL" title="OpenSSL">OpenSSL</a> version 1.0.1 or later.</li> <li><a href="/wiki/Botan_(programming_library)" title="Botan (programming library)">Botan</a> (the C++ crypto library) contains an implementation of SRP-6a</li> <li><a href="/wiki/TLS-SRP" title="TLS-SRP">TLS-SRP</a> is a set of ciphersuites for <a href="/wiki/Transport_layer_security" class="mw-redirect" title="Transport layer security">transport layer security</a> that uses SRP.</li> <li><a rel="nofollow" class="external text" href="https://github.com/symeapp/srp-client">srp-client</a> SRP-6a implementation in <a href="/wiki/JavaScript" title="JavaScript">JavaScript</a> (compatible with RFC 5054), open source, <a href="/wiki/Mozilla_Public_License" title="Mozilla Public License">Mozilla Public License</a> (MPL) licensed.</li> <li>The <a rel="nofollow" class="external text" href="https://clipperz.is/open_source/javascript_crypto_library">JavaScript Crypto Library</a> includes a JavaScript implementation of the SRP protocol, open source, <a href="/wiki/Berkeley_Software_Distribution" title="Berkeley Software Distribution">BSD</a> licensed.</li> <li><a rel="nofollow" class="external text" href="https://www.gnu.org/software/gnu-crypto/">Gnu Crypto</a> provide a <a href="/wiki/Java_(programming_language)" title="Java (programming language)">Java</a> implementation licensed under the <a href="/wiki/GNU_General_Public_License" title="GNU General Public License">GNU General Public License</a> with the "library exception", which permits its use as a library in conjunction with non-Free software.</li> <li><a href="/wiki/Bouncy_Castle_(cryptography)" title="Bouncy Castle (cryptography)">The Legion of the Bouncy Castle</a> provides Java and <a href="/wiki/C_Sharp_(programming_language)" title="C Sharp (programming language)">C#</a> implementations under the <a href="/wiki/MIT_License" title="MIT License">MIT License</a>.</li> <li><a rel="nofollow" class="external text" href="http://connect2id.com/products/nimbus-srp">Nimbus SRP</a> is a Java library providing a verifier generator, client and server-side sessions. Includes interfaces for custom password key, client and server evidence message routines. No external dependencies. Released under the <a href="/wiki/Apache_License" title="Apache License">Apache 2.0 license</a>.</li> <li><a rel="nofollow" class="external text" href="https://code.google.com/p/srplibcpp/">srplibcpp</a> is a C++ implement base on <a href="/w/index.php?title=MIRACL_(software)&amp;action=edit&amp;redlink=1" class="new" title="MIRACL (software) (page does not exist)">MIRACL</a>.</li> <li><a rel="nofollow" class="external text" href="https://github.com/slechta/DragonSRP/">DragonSRP</a> is a C++ modular implementation currently works with <a href="/wiki/OpenSSL" title="OpenSSL">OpenSSL</a>.</li> <li><a href="/wiki/Json2Ldap" title="Json2Ldap">Json2Ldap</a> provides SRP-6a authentication to <a href="/wiki/Lightweight_Directory_Access_Protocol" title="Lightweight Directory Access Protocol">LDAP</a> directory servers.</li> <li><a rel="nofollow" class="external text" href="https://github.com/cocagne/csrp">csrp</a> SRP-6a implementation in C.</li> <li><a rel="nofollow" class="external text" href="https://search.cpan.org/~mik/Crypt-SRP/">Crypt-SRP</a> SRP-6a implementation in <a href="/wiki/Perl" title="Perl">Perl</a>.</li> <li><a rel="nofollow" class="external text" href="https://github.com/cocagne/pysrp">pysrp</a> SRP-6a implementation in <a href="/wiki/Python_(programming_language)" title="Python (programming language)">Python</a> (compatible with <a rel="nofollow" class="external text" href="https://code.google.com/p/csrp/">csrp</a>).</li> <li><a rel="nofollow" class="external text" href="https://bitbucket.org/pbleyer/py3srp">py3srp</a> SRP-6a implementation in pure <a href="/wiki/Python_(programming_language)" title="Python (programming language)">Python3</a>.</li> <li><a rel="nofollow" class="external text" href="https://pypi.org/project/srptools/">srptools</a> Tools to implement Secure Remote Password (SRP) authentication in <a href="/wiki/Python_(programming_language)" title="Python (programming language)">Python</a>. <a rel="nofollow" class="external text" href="https://github.com/secure-remote-password/implementations">Verified compatible libraries</a>.</li> <li><a rel="nofollow" class="external text" href="http://meteor.com/">Meteor</a> web framework's Accounts system implements SRP for password authentication.</li> <li><a rel="nofollow" class="external text" href="https://github.com/lamikae/srp-rb">srp-rb</a> SRP-6a implementation in <a href="/wiki/Ruby_(programming_language)" title="Ruby (programming language)">Ruby</a>.</li> <li><a rel="nofollow" class="external text" href="https://github.com/falkmueller/srp">falkmueller</a> <a rel="nofollow" class="external text" href="https://code.falk-m.de/srp/">demo SRP-6a</a> implementation of the <a href="/wiki/Stanford_University" title="Stanford University">Stanford</a> SRP Protocol Design in <a href="/wiki/JavaScript" title="JavaScript">JavaScript</a> and <a href="/wiki/PHP" title="PHP">PHP</a> under the <a href="/wiki/MIT_License" title="MIT License">MIT License</a>.</li> <li><a rel="nofollow" class="external text" href="https://github.com/RuslanZavacky/srp-6a-demo">srp-6a-demo</a> SRP-6a implementation in <a href="/wiki/PHP" title="PHP">PHP</a> and <a href="/wiki/JavaScript" title="JavaScript">JavaScript</a>.</li> <li><a rel="nofollow" class="external text" href="https://bitbucket.org/simon_massey/thinbus-srp-js">thinbus-srp-js</a> SRP-6a implementation in <a href="/wiki/JavaScript" title="JavaScript">JavaScript</a>. Comes with compatible <a href="/wiki/Java_(programming_language)" title="Java (programming language)">Java</a> classes which use <a rel="nofollow" class="external text" href="http://software.dzhuvinov.com/nimbus-srp.html">Nimbus SRP</a> a demonstration app using <a href="/wiki/Spring_Security" title="Spring Security">Spring Security</a>. There is also a demonstration application performing authentication to a <a href="/wiki/PHP" title="PHP">PHP</a> server. Released under the <a href="/wiki/Apache_License" title="Apache License">Apache License</a>.</li> <li><a rel="nofollow" class="external text" href="https://bitwiseshiftleft.github.io/sjcl/">Stanford JavaScript Crypto Library (SJCL)</a> implements SRP for key exchange.</li> <li><a rel="nofollow" class="external text" href="https://github.com/mozilla/node-srp">node-srp</a> is a JavaScript client and server (node.js) implementation of SRP.</li> <li><a rel="nofollow" class="external text" href="https://sourceforge.net/projects/srp6-for-csharp-and-java/">SRP6 for C# and Java</a> implementation in C# and Java.</li> <li><a rel="nofollow" class="external text" href="https://github.com/AddAloner/ALOSRPAuth">ALOSRPAuth</a> is an Objective-C implementation of SRP-6a.</li> <li><a rel="nofollow" class="external text" href="https://github.com/opencoff/go-srp">go-srp</a> is a Go implementation of SRP-6a.</li> <li><a rel="nofollow" class="external text" href="https://github.com/midonet/tssrp6a">tssrp6a</a> is a TypeScript implementation of SRP-6a.</li> <li><a rel="nofollow" class="external text" href="https://github.com/theicenet/theicenet-cryptography">TheIceNet Cryptography</a> Java library to develop cryptography-based Spring Boot applications. Implements SRP-6a. Under <a href="/wiki/Apache_License" title="Apache License">Apache License</a>.</li> <li><a rel="nofollow" class="external text" href="https://github.com/secure-remote-password/srp.net">SRP-6a</a> in .NET implementation of SRP-6a</li> <li><a rel="nofollow" class="external text" href="https://support.apple.com/guide/security/homekit-communication-security-sec3a881ccb1/web">Apple Homekit</a> <a href="/wiki/Apple_Homekit" class="mw-redirect" title="Apple Homekit">Apple Homekit</a> uses SRP when pairing with "smart" home accessories &amp; devices</li> <li><a rel="nofollow" class="external text" href="https://proton.me/blog/encrypted-email-authentication">Proton Mail</a> Authentication for Email Encryption</li> <li><a rel="nofollow" class="external text" href="https://github.com/posterity/srp">SRP</a> is a Go implementation of SRP, used to authenticate users on <a rel="nofollow" class="external text" href="https://posterity.life">Posterity</a>.</li></ul> <div class="mw-heading mw-heading2"><h2 id="History">History</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_Remote_Password_protocol&amp;action=edit&amp;section=8" title="Edit section: History"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The SRP project was started in 1997.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">&#91;</span>11<span class="cite-bracket">&#93;</span></a></sup> Two different approaches to fixing a security hole in SRP-1 resulted in SRP-2 and SRP-3.<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">&#91;</span>12<span class="cite-bracket">&#93;</span></a></sup> SRP-3 was first published in 1998 in a conference.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">&#91;</span>13<span class="cite-bracket">&#93;</span></a></sup> RFC 2945, which describes SRP-3 with SHA1, was published in 2000.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">&#91;</span>14<span class="cite-bracket">&#93;</span></a></sup> SRP-6, which fixes "two-for-one" guessing and messaging ordering attacks, was published in 2002.<sup id="cite_ref-srp6_8-1" class="reference"><a href="#cite_note-srp6-8"><span class="cite-bracket">&#91;</span>8<span class="cite-bracket">&#93;</span></a></sup> SRP-6a appeared in the official "libsrp" in version 2.1.0, dated 2005.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">&#91;</span>15<span class="cite-bracket">&#93;</span></a></sup> SRP-6a is found in standards as: </p> <ul><li>ISO/IEC 11770-4:2006 "Key Agreement Mechanism 2" (calls the method "SRP-6, but has the <i>k</i> calculation of 6a)</li> <li>RFC 5054 TLS-SRP of 2007 (again referred to as "SRP-6", but corrected in erratum<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">&#91;</span>16<span class="cite-bracket">&#93;</span></a></sup>)</li> <li>IEEE Std 1363.2-2008 "DLAPKAS-SRP6" (again referred to as "SRP-6")<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">&#91;</span>17<span class="cite-bracket">&#93;</span></a></sup></li></ul> <p>IEEE 1363.2 also includes a description of "SRP5", a variant replacing the discrete logarithm with an <a href="/wiki/Elliptic_curve" title="Elliptic curve">elliptic curve</a> contributed by Yongge Wang in 2001.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">&#91;</span>18<span class="cite-bracket">&#93;</span></a></sup> It also describes SRP-3 as found in RFC 2945. </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_Remote_Password_protocol&amp;action=edit&amp;section=9" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Challenge%E2%80%93response_authentication" title="Challenge–response authentication">Challenge–response authentication</a></li> <li><a href="/wiki/Password-authenticated_key_agreement" title="Password-authenticated key agreement">Password-authenticated key agreement</a></li> <li><a href="/wiki/Salted_Challenge_Response_Authentication_Mechanism" title="Salted Challenge Response Authentication Mechanism">Salted Challenge Response Authentication Mechanism</a> (SCRAM)</li> <li><a href="/wiki/SPEKE" title="SPEKE">Simple Password Exponential Key Exchange</a></li> <li><a href="/wiki/Zero-knowledge_password_proof" title="Zero-knowledge password proof">Zero-knowledge password proof</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_Remote_Password_protocol&amp;action=edit&amp;section=10" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://srp.stanford.edu/whatisit.html">"What is SRP?"</a>. <a href="/wiki/Stanford_University" title="Stanford University">Stanford University</a>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=unknown&amp;rft.btitle=What+is+SRP%3F&amp;rft.pub=Stanford+University&amp;rft_id=http%3A%2F%2Fsrp.stanford.edu%2Fwhatisit.html&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+Remote+Password+protocol" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFShermanLanusLiskovZieglar2020" class="citation cs2">Sherman, Alan T.; Lanus, Erin; Liskov, Moses; Zieglar, Edward; Chang, Richard; Golaszewski, Enis; Wnuk-Fink, Ryan; Bonyadi, Cyrus J.; Yaksetig, Mario (2020), Nigam, Vivek; Ban Kirigin, Tajana; Talcott, Carolyn; Guttman, Joshua (eds.), "Formal Methods Analysis of the Secure Remote Password Protocol", <i>Logic, Language, and Security: Essays Dedicated to Andre Scedrov on the Occasion of His 65th Birthday</i>, Lecture Notes in Computer Science, Cham: Springer International Publishing, pp.&#160;103–126, <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/2003.07421">2003.07421</a></span>, <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2F978-3-030-62077-6_9">10.1007/978-3-030-62077-6_9</a>, <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&#160;<a href="/wiki/Special:BookSources/978-3-030-62077-6" title="Special:BookSources/978-3-030-62077-6"><bdi>978-3-030-62077-6</bdi></a></cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.jtitle=Logic%2C+Language%2C+and+Security%3A+Essays+Dedicated+to+Andre+Scedrov+on+the+Occasion+of+His+65th+Birthday&amp;rft.atitle=Formal+Methods+Analysis+of+the+Secure+Remote+Password+Protocol&amp;rft.pages=103-126&amp;rft.date=2020&amp;rft_id=info%3Aarxiv%2F2003.07421&amp;rft_id=info%3Adoi%2F10.1007%2F978-3-030-62077-6_9&amp;rft.isbn=978-3-030-62077-6&amp;rft.aulast=Sherman&amp;rft.aufirst=Alan+T.&amp;rft.au=Lanus%2C+Erin&amp;rft.au=Liskov%2C+Moses&amp;rft.au=Zieglar%2C+Edward&amp;rft.au=Chang%2C+Richard&amp;rft.au=Golaszewski%2C+Enis&amp;rft.au=Wnuk-Fink%2C+Ryan&amp;rft.au=Bonyadi%2C+Cyrus+J.&amp;rft.au=Yaksetig%2C+Mario&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+Remote+Password+protocol" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGreen2018" class="citation web cs1">Green, Matthew (18 October 2018). <a rel="nofollow" class="external text" href="https://blog.cryptographyengineering.com/should-you-use-srp/">"Should you use SRP?"</a>. <i>A Few Thoughts on Cryptographic Engineering</i>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=unknown&amp;rft.jtitle=A+Few+Thoughts+on+Cryptographic+Engineering&amp;rft.atitle=Should+you+use+SRP%3F&amp;rft.date=2018-10-18&amp;rft.aulast=Green&amp;rft.aufirst=Matthew&amp;rft_id=https%3A%2F%2Fblog.cryptographyengineering.com%2Fshould-you-use-srp%2F&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+Remote+Password+protocol" class="Z3988"></span> NB: source refers to SRP-6 as SRPv4 for reason unknown.</span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHaase2023" class="citation web cs1">Haase, Björn (22 January 2023). <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/draft-haase-aucpace-07">"(strong) AuCPace, an augmented PAKE &#91;draft-haase-aucpace-07&#93;"</a>. Internet Engineering Task Force<span class="reference-accessdate">. Retrieved <span class="nowrap">10 June</span> 2023</span>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=unknown&amp;rft.btitle=%28strong%29+AuCPace%2C+an+augmented+PAKE+%5Bdraft-haase-aucpace-07%5D&amp;rft.pub=Internet+Engineering+Task+Force&amp;rft.date=2023-01-22&amp;rft.aulast=Haase&amp;rft.aufirst=Bj%C3%B6rn&amp;rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Fdraft-haase-aucpace-07&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+Remote+Password+protocol" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStanislaw_JareckiHugo_KrawczykJiayu_Xu" class="citation conference cs1">Stanislaw Jarecki; Hugo Krawczyk; Jiayu Xu. <a rel="nofollow" class="external text" href="https://eprint.iacr.org/2018/163.pdf"><i>OPAQUE: An Asymmetric PAKE Protoco lSecure Against Pre-Computation Attacks</i></a> <span class="cs1-format">(PDF)</span>. Eurocrypt 2018.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=conference&amp;rft.btitle=OPAQUE%3A+An+Asymmetric+PAKE+Protoco+lSecure+Against+Pre-Computation+Attacks&amp;rft.au=Stanislaw+Jarecki&amp;rft.au=Hugo+Krawczyk&amp;rft.au=Jiayu+Xu&amp;rft_id=https%3A%2F%2Feprint.iacr.org%2F2018%2F163.pdf&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+Remote+Password+protocol" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTaylorTom_WuNikos_MavrogiannopoulosTrevor_Perrin2007" class="citation web cs1">Taylor, David; Tom Wu; Nikos Mavrogiannopoulos; Trevor Perrin (November 2007). <a rel="nofollow" class="external text" href="http://tools.ietf.org/html/rfc5054">"Using the Secure Remote Password (SRP) Protocol for TLS Authentication"</a>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=unknown&amp;rft.btitle=Using+the+Secure+Remote+Password+%28SRP%29+Protocol+for+TLS+Authentication&amp;rft.date=2007-11&amp;rft.aulast=Taylor&amp;rft.aufirst=David&amp;rft.au=Tom+Wu&amp;rft.au=Nikos+Mavrogiannopoulos&amp;rft.au=Trevor+Perrin&amp;rft_id=http%3A%2F%2Ftools.ietf.org%2Fhtml%2Frfc5054&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+Remote+Password+protocol" class="Z3988"></span> RFC 5054</span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCarlsonBernard_AbobaHenry_Haverinen2001" class="citation web cs1">Carlson, James; Bernard Aboba; Henry Haverinen (July 2001). <a rel="nofollow" class="external text" href="http://tools.ietf.org/html/draft-ietf-pppext-eap-srp-03">"EAP SRP-SHA1 Authentication Protocol"</a>. IETF.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=unknown&amp;rft.btitle=EAP+SRP-SHA1+Authentication+Protocol&amp;rft.pub=IETF&amp;rft.date=2001-07&amp;rft.aulast=Carlson&amp;rft.aufirst=James&amp;rft.au=Bernard+Aboba&amp;rft.au=Henry+Haverinen&amp;rft_id=http%3A%2F%2Ftools.ietf.org%2Fhtml%2Fdraft-ietf-pppext-eap-srp-03&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+Remote+Password+protocol" class="Z3988"></span> Draft.</span> </li> <li id="cite_note-srp6-8"><span class="mw-cite-backlink">^ <a href="#cite_ref-srp6_8-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-srp6_8-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWu2002" class="citation techreport cs1">Wu, Tom (October 29, 2002). <a rel="nofollow" class="external text" href="http://srp.stanford.edu/srp6.ps"><i>SRP-6: Improvements and Refinements to the Secure Remote Password Protocol</i></a> (Technical report).</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=report&amp;rft.btitle=SRP-6%3A+Improvements+and+Refinements+to+the+Secure+Remote+Password+Protocol&amp;rft.date=2002-10-29&amp;rft.aulast=Wu&amp;rft.aufirst=Tom&amp;rft_id=http%3A%2F%2Fsrp.stanford.edu%2Fsrp6.ps&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+Remote+Password+protocol" class="Z3988"></span></span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://srp.stanford.edu/design.html">"SRP Protocol Design"</a>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=unknown&amp;rft.btitle=SRP+Protocol+Design&amp;rft_id=http%3A%2F%2Fsrp.stanford.edu%2Fdesign.html&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+Remote+Password+protocol" class="Z3988"></span></span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://dl.acm.org/doi/10.1145/3460120.3484563">"PARASITE: PAssword Recovery Attack against Srp Implementations in ThE wild"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">8 November</span> 2023</span>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=unknown&amp;rft.btitle=PARASITE%3A+PAssword+Recovery+Attack+against+Srp+Implementations+in+ThE+wild&amp;rft_id=https%3A%2F%2Fdl.acm.org%2Fdoi%2F10.1145%2F3460120.3484563&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+Remote+Password+protocol" class="Z3988"></span></span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://srp.stanford.edu/project.html">"SRP: About the Project"</a>. <i>srp.stanford.edu</i>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=unknown&amp;rft.jtitle=srp.stanford.edu&amp;rft.atitle=SRP%3A+About+the+Project&amp;rft_id=http%3A%2F%2Fsrp.stanford.edu%2Fproject.html&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+Remote+Password+protocol" class="Z3988"></span></span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://srp.stanford.edu/design2.html">"SRP-2: Design Specifications"</a>. <i>srp.stanford.edu</i>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=unknown&amp;rft.jtitle=srp.stanford.edu&amp;rft.atitle=SRP-2%3A+Design+Specifications&amp;rft_id=http%3A%2F%2Fsrp.stanford.edu%2Fdesign2.html&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+Remote+Password+protocol" class="Z3988"></span></span> </li> <li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text">Wu, T., "<a rel="nofollow" class="external text" href="http://srp.stanford.edu/ndss.html">The Secure Remote Password Protocol</a>", Proceedings of the 1998 Internet Society Network and Distributed System Security Symposium pp. 97-111, March 1998.</span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://srp.stanford.edu/design3.html">"SRP: Design Specifications"</a>. <i>srp.stanford.edu</i>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=unknown&amp;rft.jtitle=srp.stanford.edu&amp;rft.atitle=SRP%3A+Design+Specifications&amp;rft_id=http%3A%2F%2Fsrp.stanford.edu%2Fdesign3.html&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+Remote+Password+protocol" class="Z3988"></span></span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text">CHANGES file in srp-2.1.2.tar.gz, available from <a rel="nofollow" class="external free" href="http://srp.stanford.edu/download.html">http://srp.stanford.edu/download.html</a></span> </li> <li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWang" class="citation web cs1">Wang, Mingye. <a rel="nofollow" class="external text" href="https://www.rfc-editor.org/errata/eid7538">"RFC Errata Report #7538"</a>. <i>RFC Editor</i><span class="reference-accessdate">. Retrieved <span class="nowrap">15 October</span> 2023</span>.</cite><span title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=unknown&amp;rft.jtitle=&#82;FC+Editor&amp;rft.atitle=&#82;FC+Errata+Report+%237538&amp;rft.aulast=Wang&amp;rft.aufirst=Mingye&amp;rft_id=https%3A%2F%2Fwww.rfc-editor.org%2Ferrata%2Feid7538&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+Remote+Password+protocol" class="Z3988"></span></span> </li> <li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text">IEEE 1363.2-2008: IEEE Standard Specification for Password-Based Public-Key Cryptographic Techniques</span> </li> <li id="cite_note-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-18">^</a></b></span> <span class="reference-text">Wang, Y., "IEEE P1363.2 Submission / D2001-06-21," [P1363.2-ecsrp-06-21.doc] A contribution by Yongge Wang for P1363.2 giving an elliptic curve version of the SRP protocol, June 21, 2001.</span> </li> </ol></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_Remote_Password_protocol&amp;action=edit&amp;section=11" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><span class="official-website"><span class="url"><a rel="nofollow" class="external text" href="http://srp.stanford.edu">Official website</a></span></span></li> <li><a rel="nofollow" class="external text" href="http://srp.stanford.edu/license.txt">SRP License</a>—BSD like open source.</li> <li><a rel="nofollow" class="external text" href="https://patents.google.com/patent/US6539479">US6539479</a> - SRP Patent (Expired on May 12, 2015 due to failure to pay maintenance fees (according to Google Patents). Originally set to expire in July 2018).</li></ul> <div class="mw-heading mw-heading3"><h3 id="Manual_pages">Manual pages</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_Remote_Password_protocol&amp;action=edit&amp;section=12" title="Edit section: Manual pages"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a rel="nofollow" class="external text" href="https://ppp.samba.org/pppd.html">pppd(8)</a>: Point-to-Point Protocol Daemon</li> <li><a rel="nofollow" class="external text" href="http://man7.org/linux/man-pages/man1/srptool.1.html">srptool(1)</a>: Simple SRP password tool</li></ul> <div class="mw-heading mw-heading3"><h3 id="RFCs">RFCs</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_Remote_Password_protocol&amp;action=edit&amp;section=13" title="Edit section: RFCs"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC&#160;<a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2944">2944</a> - Telnet Authentication: SRP</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC&#160;<a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2945">2945</a> - The SRP Authentication and Key Exchange System (version 3)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC&#160;<a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3720">3720</a> - Internet Small Computer Systems Interface (iSCSI)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC&#160;<a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3723">3723</a> - Securing Block Storage Protocols over IP</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC&#160;<a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3669">3669</a> - Guidelines for Working Groups on Intellectual Property Issues</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC&#160;<a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5054">5054</a> - Using the Secure Remote Password (SRP) Protocol for TLS Authentication</li></ul> <div class="mw-heading mw-heading3"><h3 id="Other_links">Other links</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_Remote_Password_protocol&amp;action=edit&amp;section=14" title="Edit section: Other links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a rel="nofollow" class="external text" href="https://archive.today/20081216020624/http://grouper.ieee.org/groups/1363/">IEEE 1363</a></li> <li><a rel="nofollow" class="external text" href="http://www.pdl.cmu.edu/mailinglists/ips/mail/msg08027.html">SRP Intellectual Property Slides (Dec 2001 - possible deprecated)</a> The EKE patents mentioned expired in 2011 and 2013.</li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol 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navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Cryptography_public-key" title="Template:Cryptography public-key"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Cryptography_public-key" title="Template talk:Cryptography public-key"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Cryptography_public-key" title="Special:EditPage/Template:Cryptography public-key"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Public-key_cryptography" style="font-size:114%;margin:0 4em"><a href="/wiki/Public-key_cryptography" title="Public-key cryptography">Public-key cryptography</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Algorithms</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group wraplinks" style="width:1%"><a href="/wiki/Integer_factorization" title="Integer factorization">Integer factorization</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Benaloh_cryptosystem" title="Benaloh cryptosystem">Benaloh</a></li> <li><a href="/wiki/Blum%E2%80%93Goldwasser_cryptosystem" title="Blum–Goldwasser cryptosystem">Blum–Goldwasser</a></li> <li><a href="/wiki/Cayley%E2%80%93Purser_algorithm" title="Cayley–Purser algorithm">Cayley–Purser</a></li> <li><a href="/wiki/Damg%C3%A5rd%E2%80%93Jurik_cryptosystem" title="Damgård–Jurik cryptosystem">Damgård–Jurik</a></li> <li><a href="/wiki/GMR_(cryptography)" title="GMR (cryptography)">GMR</a></li> <li><a href="/wiki/Goldwasser%E2%80%93Micali_cryptosystem" title="Goldwasser–Micali cryptosystem">Goldwasser–Micali</a></li> <li><a href="/wiki/Naccache%E2%80%93Stern_cryptosystem" title="Naccache–Stern cryptosystem">Naccache–Stern</a></li> <li><a href="/wiki/Paillier_cryptosystem" title="Paillier cryptosystem">Paillier</a></li> <li><a href="/wiki/Rabin_cryptosystem" title="Rabin cryptosystem">Rabin</a></li> <li><a href="/wiki/RSA_(cryptosystem)" title="RSA (cryptosystem)">RSA</a></li> <li><a href="/wiki/Okamoto%E2%80%93Uchiyama_cryptosystem" title="Okamoto–Uchiyama cryptosystem">Okamoto–Uchiyama</a></li> <li><a href="/wiki/Schmidt-Samoa_cryptosystem" title="Schmidt-Samoa cryptosystem">Schmidt–Samoa</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group wraplinks" style="width:1%"><a href="/wiki/Discrete_logarithm" title="Discrete logarithm">Discrete logarithm</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Boneh%E2%80%93Lynn%E2%80%93Shacham" class="mw-redirect" title="Boneh–Lynn–Shacham">BLS</a></li> <li><a href="/wiki/Cramer%E2%80%93Shoup_cryptosystem" title="Cramer–Shoup cryptosystem">Cramer–Shoup</a></li> <li><a href="/wiki/Diffie%E2%80%93Hellman_key_exchange" title="Diffie–Hellman key exchange">DH</a></li> <li><a href="/wiki/Digital_Signature_Algorithm" title="Digital Signature Algorithm">DSA</a></li> <li><a href="/wiki/Elliptic-curve_Diffie%E2%80%93Hellman" title="Elliptic-curve Diffie–Hellman">ECDH</a> <ul><li><a href="/wiki/Curve25519" title="Curve25519">X25519</a></li> <li><a href="/wiki/Curve448" title="Curve448">X448</a></li></ul></li> <li><a href="/wiki/Elliptic_Curve_Digital_Signature_Algorithm" title="Elliptic Curve Digital Signature Algorithm">ECDSA</a></li> <li><a href="/wiki/EdDSA" title="EdDSA">EdDSA</a> <ul><li><a href="/wiki/EdDSA#Ed25519" title="EdDSA">Ed25519</a></li> <li><a href="/wiki/EdDSA#Ed448" title="EdDSA">Ed448</a></li></ul></li> <li><a href="/wiki/ECMQV" class="mw-redirect" title="ECMQV">ECMQV</a></li> <li><a href="/wiki/Encrypted_key_exchange" title="Encrypted key exchange">EKE</a></li> <li><a href="/wiki/ElGamal_encryption" title="ElGamal encryption">ElGamal</a> <ul><li><a href="/wiki/ElGamal_signature_scheme" title="ElGamal signature scheme">signature scheme</a></li></ul></li> <li><a href="/wiki/MQV" title="MQV">MQV</a></li> <li><a href="/wiki/Schnorr_signature" title="Schnorr signature">Schnorr</a></li> <li><a href="/wiki/SPEKE" title="SPEKE">SPEKE</a></li> <li><a class="mw-selflink selflink">SRP</a></li> <li><a href="/wiki/Station-to-Station_protocol" title="Station-to-Station protocol">STS</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group wraplinks" style="width:1%"><a href="/wiki/Lattice-based_cryptography" title="Lattice-based cryptography">Lattice/SVP/CVP</a>/<wbr /><a href="/wiki/Learning_with_errors" title="Learning with errors">LWE</a>/<wbr /><a href="/wiki/Short_integer_solution_problem" title="Short integer solution problem">SIS</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/BLISS_signature_scheme" title="BLISS signature scheme">BLISS</a></li> <li><a href="/wiki/Kyber" title="Kyber">Kyber</a></li> <li><a href="/wiki/NewHope" title="NewHope">NewHope</a></li> <li><a href="/wiki/NTRUEncrypt" title="NTRUEncrypt">NTRUEncrypt</a></li> <li><a href="/wiki/NTRUSign" title="NTRUSign">NTRUSign</a></li> <li><a href="/wiki/RLWE-KEX" class="mw-redirect" title="RLWE-KEX">RLWE-KEX</a></li> <li><a href="/wiki/RLWE-SIG" class="mw-redirect" title="RLWE-SIG">RLWE-SIG</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group wraplinks" style="width:1%">Others</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Algebraic_Eraser" title="Algebraic Eraser">AE</a></li> <li><a href="/wiki/CEILIDH" title="CEILIDH">CEILIDH</a></li> <li><a href="/wiki/Efficient_Probabilistic_Public-Key_Encryption_Scheme" title="Efficient Probabilistic Public-Key Encryption Scheme">EPOC</a></li> <li><a href="/wiki/Hidden_Field_Equations" title="Hidden Field Equations">HFE</a></li> <li><a href="/wiki/Integrated_Encryption_Scheme" title="Integrated Encryption Scheme">IES</a></li> <li><a href="/wiki/Lamport_signature" title="Lamport signature">Lamport</a></li> <li><a href="/wiki/McEliece_cryptosystem" title="McEliece cryptosystem">McEliece</a></li> <li><a href="/wiki/Merkle%E2%80%93Hellman_knapsack_cryptosystem" title="Merkle–Hellman knapsack cryptosystem">Merkle–Hellman</a></li> <li><span class="wraplinks"><a href="/wiki/Naccache%E2%80%93Stern_knapsack_cryptosystem" title="Naccache–Stern knapsack cryptosystem">Naccache–Stern knapsack cryptosystem</a></span></li> <li><a href="/wiki/Three-pass_protocol" title="Three-pass protocol">Three-pass protocol</a></li> <li><a href="/wiki/XTR" title="XTR">XTR</a></li> <li><a href="/wiki/SQIsign" title="SQIsign">SQIsign</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Theory</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Discrete_logarithm#Cryptography" title="Discrete logarithm">Discrete logarithm cryptography</a></li> <li><a href="/wiki/Elliptic-curve_cryptography" title="Elliptic-curve cryptography">Elliptic-curve cryptography</a></li> <li><a href="/wiki/Hash-based_cryptography" title="Hash-based cryptography">Hash-based cryptography</a></li> <li><a href="/wiki/Non-commutative_cryptography" title="Non-commutative cryptography">Non-commutative cryptography</a></li> <li><a href="/wiki/RSA_problem" title="RSA problem">RSA problem</a></li> <li><a href="/wiki/Trapdoor_function" title="Trapdoor function">Trapdoor function</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Standardization</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/CRYPTREC" title="CRYPTREC">CRYPTREC</a></li> <li><a href="/wiki/IEEE_P1363" title="IEEE P1363">IEEE P1363</a></li> <li><a href="/wiki/NESSIE" title="NESSIE">NESSIE</a></li> <li><a href="/wiki/NSA_Suite_B_Cryptography" title="NSA Suite B Cryptography">NSA Suite B</a></li> <li><a href="/wiki/Commercial_National_Security_Algorithm_Suite" title="Commercial National Security Algorithm Suite">CNSA</a></li> <li><a href="/wiki/NIST_Post-Quantum_Cryptography_Standardization" title="NIST Post-Quantum Cryptography Standardization">Post-Quantum Cryptography</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Topics</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Digital_signature" title="Digital signature">Digital signature</a></li> <li><a href="/wiki/Optimal_asymmetric_encryption_padding" title="Optimal asymmetric encryption padding">OAEP</a></li> <li><a href="/wiki/Public_key_fingerprint" title="Public key fingerprint">Fingerprint</a></li> <li><a href="/wiki/Public_key_infrastructure" title="Public key infrastructure">PKI</a></li> <li><a href="/wiki/Web_of_trust" title="Web of trust">Web of trust</a></li> <li><a href="/wiki/Key_size" title="Key size">Key size</a></li> <li><a href="/wiki/Identity-based_cryptography" title="Identity-based cryptography">Identity-based cryptography</a></li> <li><a href="/wiki/Post-quantum_cryptography" title="Post-quantum cryptography">Post-quantum cryptography</a></li> <li><a href="/wiki/OpenPGP_card" title="OpenPGP card">OpenPGP card</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr></tbody></table><div></div></td></tr><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks mw-collapsible mw-collapsed navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Cryptography_navbox" title="Template:Cryptography navbox"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Cryptography_navbox" title="Template talk:Cryptography navbox"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Cryptography_navbox" title="Special:EditPage/Template:Cryptography navbox"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Cryptography" style="font-size:114%;margin:0 4em"><a href="/wiki/Cryptography" title="Cryptography">Cryptography</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">General</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/History_of_cryptography" title="History of cryptography">History of cryptography</a></li> <li><a href="/wiki/Outline_of_cryptography" title="Outline of cryptography">Outline of cryptography</a></li> <li><a href="/wiki/Classical_cipher" title="Classical cipher">Classical cipher</a></li> <li><a href="/wiki/Cryptographic_protocol" title="Cryptographic protocol">Cryptographic protocol</a> <ul><li><a href="/wiki/Authentication_protocol" title="Authentication protocol">Authentication protocol</a></li></ul></li> <li><a href="/wiki/Cryptographic_primitive" title="Cryptographic primitive">Cryptographic primitive</a></li> <li><a href="/wiki/Cryptanalysis" title="Cryptanalysis">Cryptanalysis</a></li> <li><a href="/wiki/Cryptocurrency" title="Cryptocurrency">Cryptocurrency</a></li> <li><a href="/wiki/Cryptosystem" title="Cryptosystem">Cryptosystem</a></li> <li><a href="/wiki/Cryptographic_nonce" title="Cryptographic nonce">Cryptographic nonce</a></li> <li><a href="/wiki/Cryptovirology" title="Cryptovirology">Cryptovirology</a></li> <li><a href="/wiki/Hash_function" title="Hash function">Hash function</a> <ul><li><a href="/wiki/Cryptographic_hash_function" title="Cryptographic hash function">Cryptographic hash function</a></li> <li><a href="/wiki/Key_derivation_function" title="Key derivation function">Key derivation function</a></li> <li><a href="/wiki/Secure_Hash_Algorithms" title="Secure Hash Algorithms">Secure Hash Algorithms</a></li></ul></li> <li><a href="/wiki/Digital_signature" title="Digital signature">Digital signature</a></li> <li><a href="/wiki/Kleptography" title="Kleptography">Kleptography</a></li> <li><a href="/wiki/Key_(cryptography)" title="Key (cryptography)">Key (cryptography)</a></li> <li><a href="/wiki/Key_exchange" title="Key exchange">Key exchange</a></li> <li><a href="/wiki/Key_generator" title="Key generator">Key generator</a></li> <li><a href="/wiki/Key_schedule" title="Key schedule">Key schedule</a></li> <li><a href="/wiki/Key_stretching" title="Key stretching">Key stretching</a></li> <li><a href="/wiki/Keygen" title="Keygen">Keygen</a></li> <li><a href="/wiki/Template:Cryptography_machines" title="Template:Cryptography machines">Machines</a></li> <li><a href="/wiki/Cryptojacking_malware" class="mw-redirect" title="Cryptojacking malware">Cryptojacking malware</a></li> <li><a href="/wiki/Ransomware" title="Ransomware">Ransomware</a></li> <li><a href="/wiki/Random_number_generation" title="Random number generation">Random number generation</a> <ul><li><a href="/wiki/Cryptographically_secure_pseudorandom_number_generator" title="Cryptographically secure pseudorandom number generator">Cryptographically secure pseudorandom number generator</a> (CSPRNG)</li></ul></li> <li><a href="/wiki/Pseudorandom_noise" title="Pseudorandom noise">Pseudorandom noise</a> (PRN)</li> <li><a href="/wiki/Secure_channel" title="Secure channel">Secure channel</a></li> <li><a href="/wiki/Insecure_channel" class="mw-redirect" title="Insecure channel">Insecure channel</a></li> <li><a href="/wiki/Subliminal_channel" title="Subliminal channel">Subliminal channel</a></li> <li><a href="/wiki/Encryption" title="Encryption">Encryption</a></li> <li><a href="/wiki/Decryption" class="mw-redirect" title="Decryption">Decryption</a></li> <li><a href="/wiki/End-to-end_encryption" title="End-to-end encryption">End-to-end encryption</a></li> <li><a href="/wiki/Harvest_now,_decrypt_later" title="Harvest now, decrypt later">Harvest now, decrypt later</a></li> <li><a href="/wiki/Information-theoretic_security" title="Information-theoretic security">Information-theoretic security</a></li> <li><a href="/wiki/Plaintext" title="Plaintext">Plaintext</a></li> <li><a href="/wiki/Codetext" class="mw-redirect" title="Codetext">Codetext</a></li> <li><a href="/wiki/Ciphertext" title="Ciphertext">Ciphertext</a></li> <li><a href="/wiki/Shared_secret" title="Shared secret">Shared secret</a></li> <li><a href="/wiki/Trapdoor_function" title="Trapdoor function">Trapdoor function</a></li> <li><a href="/wiki/Trusted_timestamping" title="Trusted timestamping">Trusted timestamping</a></li> <li><a href="/wiki/Key-based_routing" title="Key-based routing">Key-based routing</a></li> <li><a href="/wiki/Onion_routing" title="Onion routing">Onion routing</a></li> <li><a href="/wiki/Garlic_routing" title="Garlic routing">Garlic routing</a></li> <li><a href="/wiki/Kademlia" title="Kademlia">Kademlia</a></li> <li><a href="/wiki/Mix_network" title="Mix network">Mix network</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Mathematics</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Cryptographic_hash_function" title="Cryptographic hash function">Cryptographic hash function</a></li> <li><a href="/wiki/Block_cipher" title="Block cipher">Block cipher</a></li> <li><a href="/wiki/Stream_cipher" title="Stream cipher">Stream cipher</a></li> <li><a href="/wiki/Symmetric-key_algorithm" title="Symmetric-key algorithm">Symmetric-key algorithm</a></li> <li><a href="/wiki/Authenticated_encryption" title="Authenticated encryption">Authenticated encryption</a></li> <li><a href="/wiki/Public-key_cryptography" title="Public-key cryptography">Public-key cryptography</a></li> <li><a href="/wiki/Quantum_key_distribution" title="Quantum key distribution">Quantum key distribution</a></li> <li><a href="/wiki/Quantum_cryptography" title="Quantum cryptography">Quantum cryptography</a></li> <li><a href="/wiki/Post-quantum_cryptography" title="Post-quantum cryptography">Post-quantum cryptography</a></li> <li><a href="/wiki/Message_authentication_code" title="Message authentication code">Message authentication code</a></li> <li><a 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