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Available in 22 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-22" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">22 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%A8%D8%B1%D9%88%D8%AA%D9%88%D9%83%D9%88%D9%84_%D8%AA%D8%B9%D9%85%D9%8A%D8%A9" title="بروتوكول تعمية – Arabic" lang="ar" hreflang="ar" data-title="بروتوكول تعمية" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Protocol_criptogr%C3%A0fic" title="Protocol criptogràfic – Catalan" lang="ca" hreflang="ca" data-title="Protocol criptogràfic" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Kryptografick%C3%BD_protokol" title="Kryptografický protokol – Czech" lang="cs" hreflang="cs" data-title="Kryptografický protokol" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Verschl%C3%BCsselungsprotokoll" title="Verschlüsselungsprotokoll – German" lang="de" hreflang="de" data-title="Verschlüsselungsprotokoll" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Protocolo_criptogr%C3%A1fico" title="Protocolo criptográfico – Spanish" lang="es" hreflang="es" data-title="Protocolo criptográfico" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%BE%D8%B1%D9%88%D8%AA%DA%A9%D9%84_%D8%B1%D9%85%D8%B2%D9%86%DA%AF%D8%A7%D8%B1%DB%8C" title="پروتکل رمزنگاری – Persian" lang="fa" hreflang="fa" data-title="پروتکل رمزنگاری" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Protocole_cryptographique" title="Protocole cryptographique – French" lang="fr" hreflang="fr" data-title="Protocole cryptographique" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Protokol_kriptografi" title="Protokol kriptografi – Indonesian" lang="id" hreflang="id" data-title="Protokol kriptografi" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Protocollo_crittografico" title="Protocollo crittografico – Italian" lang="it" hreflang="it" data-title="Protocollo crittografico" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%A4%D7%A8%D7%95%D7%98%D7%95%D7%A7%D7%95%D7%9C_%D7%A7%D7%A8%D7%99%D7%A4%D7%98%D7%95%D7%92%D7%A8%D7%A4%D7%99" title="פרוטוקול קריפטוגרפי – Hebrew" lang="he" hreflang="he" data-title="פרוטוקול קריפטוגרפי" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-ka mw-list-item"><a href="https://ka.wikipedia.org/wiki/%E1%83%99%E1%83%A0%E1%83%98%E1%83%9E%E1%83%A2%E1%83%9D%E1%83%92%E1%83%A0%E1%83%90%E1%83%A4%E1%83%98%E1%83%A3%E1%83%9A%E1%83%98_%E1%83%9E%E1%83%A0%E1%83%9D%E1%83%A2%E1%83%9D%E1%83%99%E1%83%9D%E1%83%9A%E1%83%98" title="კრიპტოგრაფიული პროტოკოლი – Georgian" lang="ka" hreflang="ka" data-title="კრიპტოგრაფიული პროტოკოლი" data-language-autonym="ქართული" data-language-local-name="Georgian" class="interlanguage-link-target"><span>ქართული</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Protokol_kriptografi" title="Protokol kriptografi – Malay" lang="ms" hreflang="ms" data-title="Protokol kriptografi" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Cryptografisch_protocol" title="Cryptografisch protocol – Dutch" lang="nl" hreflang="nl" data-title="Cryptografisch protocol" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Protok%C3%B3%C5%82_kryptograficzny" title="Protokół kryptograficzny – Polish" lang="pl" hreflang="pl" data-title="Protokół kryptograficzny" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Protocolo_de_seguran%C3%A7a" title="Protocolo de segurança – Portuguese" lang="pt" hreflang="pt" data-title="Protocolo de segurança" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%9A%D1%80%D0%B8%D0%BF%D1%82%D0%BE%D0%B3%D1%80%D0%B0%D1%84%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B8%D0%B9_%D0%BF%D1%80%D0%BE%D1%82%D0%BE%D0%BA%D0%BE%D0%BB" title="Криптографический протокол – Russian" lang="ru" hreflang="ru" data-title="Криптографический протокол" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Cryptographic_protocol" title="Cryptographic protocol – Simple English" lang="en-simple" hreflang="en-simple" data-title="Cryptographic protocol" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Salausprotokolla" title="Salausprotokolla – Finnish" lang="fi" hreflang="fi" data-title="Salausprotokolla" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%9A%D1%80%D0%B8%D0%BF%D1%82%D0%BE%D0%B3%D1%80%D0%B0%D1%84%D1%96%D1%87%D0%BD%D0%B8%D0%B9_%D0%BF%D1%80%D0%BE%D1%82%D0%BE%D0%BA%D0%BE%D0%BB" title="Криптографічний протокол – Ukrainian" lang="uk" hreflang="uk" data-title="Криптографічний протокол" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Giao_th%E1%BB%A9c_m%E1%BA%ADt_m%C3%A3" title="Giao thức mật mã – Vietnamese" lang="vi" hreflang="vi" data-title="Giao thức mật mã" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-zh-yue mw-list-item"><a href="https://zh-yue.wikipedia.org/wiki/%E5%AF%86%E7%A2%BC%E5%8D%94%E8%AD%B0" title="密碼協議 – Cantonese" lang="yue" hreflang="yue" data-title="密碼協議" data-language-autonym="粵語" data-language-local-name="Cantonese" class="interlanguage-link-target"><span>粵語</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E5%AE%89%E5%85%A8%E5%8D%8F%E8%AE%AE" title="安全协议 – 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<div class="mw-indicators"> </div> <div id="siteSub" 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">Aspect of cryptography</div> <p>A <b>cryptographic protocol</b> is an abstract or concrete <a href="/wiki/Communications_protocol" class="mw-redirect" title="Communications protocol">protocol</a> that performs a <a href="/wiki/Information_security" title="Information security">security</a>-related function and applies <a href="/wiki/Cryptographic" class="mw-redirect" title="Cryptographic">cryptographic</a> methods, often as sequences of <a href="/wiki/Cryptographic_primitive" title="Cryptographic primitive">cryptographic primitives</a>. A protocol describes how the algorithms should be used and includes details about data structures and representations, at which point it can be used to implement multiple, interoperable versions of a program.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>Cryptographic protocols are widely used for secure application-level data transport. A cryptographic protocol usually incorporates at least some of these aspects: </p> <ul><li><a href="/wiki/Key_agreement" class="mw-redirect" title="Key agreement">Key agreement</a> or establishment</li> <li>Entity <a href="/wiki/Authentication" title="Authentication">authentication</a></li> <li>Symmetric <a href="/wiki/Encryption" title="Encryption">encryption</a> and message authentication <a href="/wiki/Key_(cryptography)" title="Key (cryptography)"> </a> material construction</li> <li>Secured application-level data transport</li> <li><a href="/wiki/Non-repudiation" title="Non-repudiation">Non-repudiation</a> methods</li> <li><a href="/wiki/Secret_sharing" title="Secret sharing">Secret sharing</a> methods</li> <li><a href="/wiki/Secure_multi-party_computation" title="Secure multi-party computation">Secure multi-party computation</a></li></ul> <p>For example, <a href="/wiki/Transport_Layer_Security" title="Transport Layer Security">Transport Layer Security</a> (TLS) is a cryptographic protocol that is used to secure web (<a href="/wiki/HTTPS" title="HTTPS">HTTPS</a>) connections.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> It has an entity authentication mechanism, based on the <a href="/wiki/X.509" title="X.509">X.509</a> system; a key setup phase, where a <a href="/wiki/Symmetric_encryption" class="mw-redirect" title="Symmetric encryption">symmetric encryption</a> key is formed by employing public-key cryptography; and an application-level data transport function. These three aspects have important interconnections. Standard TLS does not have non-repudiation support. </p><p>There are other types of cryptographic protocols as well, and even the term itself has various readings; Cryptographic <i>application</i> protocols often use one or more underlying <a href="/wiki/Key_agreement" class="mw-redirect" title="Key agreement">key agreement methods</a>, which are also sometimes themselves referred to as "cryptographic protocols". For instance, TLS employs what is known as the <a href="/wiki/Diffie%E2%80%93Hellman_key_exchange" title="Diffie–Hellman key exchange">Diffie–Hellman key exchange</a>, which although it is only a part of TLS <i>per se</i>, Diffie–Hellman may be seen as a complete cryptographic protocol in itself for other applications. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Advanced_cryptographic_protocols">Advanced cryptographic protocols</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cryptographic_protocol&action=edit&section=1" title="Edit section: Advanced cryptographic protocols"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A wide variety of cryptographic protocols go beyond the traditional goals of data confidentiality, integrity, and authentication to also secure a variety of other desired characteristics of computer-mediated collaboration.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Blind_signature" title="Blind signature">Blind signatures</a> can be used for <a href="/wiki/Ecash" title="Ecash">digital cash</a> and <a href="/wiki/Digital_credential" title="Digital credential">digital credentials</a> to prove that a person holds an attribute or right without revealing that person's identity or the identities of parties that person transacted with. <a href="/wiki/Trusted_timestamping" title="Trusted timestamping">Secure digital timestamping</a> can be used to prove that data (even if confidential) existed at a certain time. <a href="/wiki/Secure_multiparty_computation" class="mw-redirect" title="Secure multiparty computation">Secure multiparty computation</a> can be used to compute answers (such as determining the highest bid in an auction) based on confidential data (such as private bids), so that when the protocol is complete the participants know only their own input and the answer. <a href="/wiki/End-to-end_auditable_voting_systems" class="mw-redirect" title="End-to-end auditable voting systems">End-to-end auditable voting systems</a> provide sets of desirable privacy and auditability properties for conducting <a href="/wiki/E-voting" class="mw-redirect" title="E-voting">e-voting</a>. <a href="/wiki/Undeniable_signature" title="Undeniable signature">Undeniable signatures</a> include interactive protocols that allow the signer to prove a forgery and limit who can verify the signature. <a href="/wiki/Deniable_encryption" title="Deniable encryption">Deniable encryption</a> augments standard encryption by making it impossible for an attacker to mathematically prove the existence of a plain text message. <a href="/w/index.php?title=Anonymous_re-mailer&action=edit&redlink=1" class="new" title="Anonymous re-mailer (page does not exist)">Digital mixes</a> create hard-to-trace communications. </p> <div class="mw-heading mw-heading2"><h2 id="Formal_verification">Formal verification</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cryptographic_protocol&action=edit&section=2" title="Edit section: Formal verification"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Cryptographic protocols can sometimes be <a href="/wiki/Formal_verification" title="Formal verification">verified formally</a> on an abstract level. When it is done, there is a necessity to formalize the environment in which the protocol operates in order to identify threats. This is frequently done through the <a href="/wiki/Dolev-Yao" class="mw-redirect" title="Dolev-Yao">Dolev-Yao</a> model. </p><p>Logics, concepts and calculi used for formal reasoning of security protocols: </p> <style data-mw-deduplicate="TemplateStyles:r1251242444">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}</style><table class="plainlinks metadata ambox mbox-small-left ambox-notice" role="presentation" style="width: auto;"><tbody><tr><td class="mbox-image"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/1/1d/Information_icon4.svg/20px-Information_icon4.svg.png" decoding="async" width="20" height="20" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/1/1d/Information_icon4.svg/30px-Information_icon4.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/1/1d/Information_icon4.svg/40px-Information_icon4.svg.png 2x" data-file-width="620" data-file-height="620" /></span></span></td><td class="mbox-text" style="width: auto;"><div class="mbox-text-span">This list is <a href="/wiki/Wikipedia:WikiProject_Lists#Incomplete_lists" title="Wikipedia:WikiProject Lists">incomplete</a>; you can help by <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Cryptographic_protocol&action=edit">adding missing items</a>. <span class="date-container"><i>(<span class="date">October 2016</span>)</i></span></div></td></tr></tbody></table> <ul><li><a href="/wiki/Burrows%E2%80%93Abadi%E2%80%93Needham_logic" title="Burrows–Abadi–Needham logic">Burrows–Abadi–Needham logic (BAN logic)</a></li> <li><a href="/wiki/Dolev%E2%80%93Yao_model" title="Dolev–Yao model">Dolev–Yao model</a></li> <li><a href="/wiki/%CE%A0-calculus" title="Π-calculus">π-calculus</a></li> <li><a href="/wiki/Protocol_composition_logic" title="Protocol composition logic">Protocol composition logic (PCL)</a></li> <li>Strand space<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup></li></ul> <p>Research projects and tools used for formal verification of security protocols: </p> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1251242444"><table class="plainlinks metadata ambox mbox-small-left ambox-notice" role="presentation" style="width: auto;"><tbody><tr><td class="mbox-image"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/1/1d/Information_icon4.svg/20px-Information_icon4.svg.png" decoding="async" width="20" height="20" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/1/1d/Information_icon4.svg/30px-Information_icon4.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/1/1d/Information_icon4.svg/40px-Information_icon4.svg.png 2x" data-file-width="620" data-file-height="620" /></span></span></td><td class="mbox-text" style="width: auto;"><div class="mbox-text-span">This list is <a href="/wiki/Wikipedia:WikiProject_Lists#Incomplete_lists" title="Wikipedia:WikiProject Lists">incomplete</a>; you can help by <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Cryptographic_protocol&action=edit">adding missing items</a>. <span class="date-container"><i>(<span class="date">October 2016</span>)</i></span></div></td></tr></tbody></table> <ul><li>Automated Validation of Internet Security Protocols and Applications (AVISPA) and follow-up project AVANTSSAR.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-TAP_1_6-0" class="reference"><a href="#cite_note-TAP_1-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> <ul><li>Constraint Logic-based Attack Searcher (CL-AtSe)<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup></li> <li>Open-Source Fixed-Point Model-Checker (OFMC)<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup></li> <li>SAT-based Model-Checker (SATMC)<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup></li></ul></li> <li>Casper<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/CryptoVerif" title="CryptoVerif">CryptoVerif</a></li> <li>Cryptographic Protocol Shapes Analyzer (CPSA)<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup></li> <li>Knowledge In Security protocolS (KISS)<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup></li> <li>Maude-NRL Protocol Analyzer (Maude-NPA)<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/ProVerif" title="ProVerif">ProVerif</a></li> <li>Scyther<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/Tamarin_Prover" title="Tamarin Prover">Tamarin Prover</a><sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup></li></ul> <div class="mw-heading mw-heading3"><h3 id="Notion_of_abstract_protocol">Notion of abstract protocol</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cryptographic_protocol&action=edit&section=3" title="Edit section: Notion of abstract protocol"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Security_protocol_notation" title="Security protocol notation">Security protocol notation</a></div> <p>To formally verify a protocol it is often abstracted and modelled using <a href="/wiki/Security_protocol_notation" title="Security protocol notation">Alice & Bob notation</a>. A simple example is the following: </p> <dl><dd><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 A\rightarrow B:\{X\}_{K_{A,B}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>A</mi> <mo stretchy="false">→</mo> <mi>B</mi> <mo>:</mo> <mo fence="false" stretchy="false">{</mo> <mi>X</mi> <msub> <mo fence="false" stretchy="false">}</mo> <mrow class="MJX-TeXAtom-ORD"> <msub> <mi>K</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> <mo>,</mo> <mi>B</mi> </mrow> </msub> </mrow> </msub> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle A\rightarrow B:\{X\}_{K_{A,B}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/8aea7612a5a95fd14f7e994131d0e1d236afe876" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.338ex; width:17.54ex; height:3.343ex;" alt="{\displaystyle A\rightarrow B:\{X\}_{K_{A,B}}}"></span></dd></dl> <p>This states that <a href="/wiki/Alice_and_Bob" title="Alice and Bob">Alice</a> <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 A}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>A</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle A}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/7daff47fa58cdfd29dc333def748ff5fa4c923e3" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.743ex; height:2.176ex;" alt="{\displaystyle A}"></span> intends a message for Bob <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 B}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>B</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle B}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/47136aad860d145f75f3eed3022df827cee94d7a" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.764ex; height:2.176ex;" alt="{\displaystyle B}"></span> consisting of a message <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 X}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>X</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle X}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/68baa052181f707c662844a465bfeeb135e82bab" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.98ex; height:2.176ex;" alt="{\displaystyle X}"></span> encrypted under shared key <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 K_{A,B}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>K</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> <mo>,</mo> <mi>B</mi> </mrow> </msub> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle K_{A,B}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/be8ac72428948492e18d61ea954ce03643d6f0f3" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.005ex; width:5.143ex; height:2.843ex;" alt="{\displaystyle K_{A,B}}"></span>. </p> <div class="mw-heading mw-heading2"><h2 id="Examples">Examples</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cryptographic_protocol&action=edit&section=4" title="Edit section: Examples"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Internet_Key_Exchange" title="Internet Key Exchange">Internet Key Exchange</a></li> <li><a href="/wiki/IPsec" title="IPsec">IPsec</a></li> <li><a href="/wiki/Kerberos_(protocol)" title="Kerberos (protocol)">Kerberos</a></li> <li><a href="/wiki/Off-the-Record_Messaging" class="mw-redirect" title="Off-the-Record Messaging">Off-the-Record Messaging</a></li> <li><a href="/wiki/Point_to_Point_Protocol" class="mw-redirect" title="Point to Point Protocol">Point to Point Protocol</a></li> <li><a href="/wiki/Secure_Shell" title="Secure Shell">Secure Shell</a> (SSH)</li> <li><a href="/wiki/Signal_Protocol" title="Signal Protocol">Signal Protocol</a></li> <li><a href="/wiki/Transport_Layer_Security" title="Transport Layer Security">Transport Layer Security</a></li> <li><a href="/wiki/ZRTP" title="ZRTP">ZRTP</a></li></ul> <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=Cryptographic_protocol&action=edit&section=5" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/List_of_cryptosystems" title="List of cryptosystems">List of cryptosystems</a></li> <li><a href="/wiki/Secure_channel" title="Secure channel">Secure channel</a></li> <li><a href="/wiki/Security_Protocols_Open_Repository" title="Security Protocols Open Repository">Security Protocols Open Repository</a></li> <li><a href="/wiki/Comparison_of_cryptography_libraries" title="Comparison of cryptography libraries">Comparison of cryptography libraries</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=Cryptographic_protocol&action=edit&section=6" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output 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Retrieved <span class="nowrap">2016-10-07</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Knowledge+In+Security+protocolS+%28KISS%29&rft_id=http%3A%2F%2Fwww.lsv.ens-cachan.fr%2F~ciobaca%2Fkiss%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACryptographic+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"><a rel="nofollow" class="external text" href="http://personales.upv.es/sanesro/Maude-NPA_Protocols/">Maude-NRL Protocol Analyzer (Maude-NPA)</a></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"><a rel="nofollow" class="external text" href="https://www.cs.ox.ac.uk/people/cas.cremers/scyther/">Scyther</a></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"><a rel="nofollow" class="external text" href="https://tamarin-prover.github.io/">Tamarin Prover</a></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cryptographic_protocol&action=edit&section=7" title="Edit section: Further reading"><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"><cite id="CITEREFErmoshinaMusianiHalpin2016" class="citation conference cs1">Ermoshina, Ksenia; Musiani, Francesca; Halpin, Harry (September 2016). <a rel="nofollow" class="external text" href="https://hal.inria.fr/hal-01426845/file/paper_21.pdf">"End-to-End Encrypted Messaging Protocols: An Overview"</a> <span class="cs1-format">(PDF)</span>. In Bagnoli, Franco; et al. (eds.). <i>Internet Science</i>. INSCI 2016. Florence, Italy: Springer. pp. 244–254. <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%2F978-3-319-45982-0_22">10.1007/978-3-319-45982-0_22</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-319-45982-0" title="Special:BookSources/978-3-319-45982-0"><bdi>978-3-319-45982-0</bdi></a>.</cite><span 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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 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