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class="vector-toc-numb">2</span> <span>Nature and limits of security</span> </div> </a> <button aria-controls="toc-Nature_and_limits_of_security-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Nature and limits of security subsection</span> </button> <ul id="toc-Nature_and_limits_of_security-sublist" class="vector-toc-list"> <li id="toc-Types_of_security" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Types_of_security"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Types of security</span> </div> </a> <ul id="toc-Types_of_security-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Borderline_cases" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Borderline_cases"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Borderline cases</span> </div> </a> <ul id="toc-Borderline_cases-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Tools_used_to_obtain_security" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Tools_used_to_obtain_security"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Tools used to obtain security</span> </div> </a> <button aria-controls="toc-Tools_used_to_obtain_security-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Tools used to obtain security subsection</span> </button> <ul id="toc-Tools_used_to_obtain_security-sublist" class="vector-toc-list"> <li id="toc-Encryption" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Encryption"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Encryption</span> </div> </a> <ul id="toc-Encryption-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Steganography" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Steganography"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>Steganography</span> </div> </a> <ul id="toc-Steganography-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Identity-based_networks" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Identity-based_networks"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.3</span> <span>Identity-based networks</span> </div> </a> <ul id="toc-Identity-based_networks-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Anonymized_networks" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Anonymized_networks"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.4</span> <span>Anonymized networks</span> </div> </a> <ul id="toc-Anonymized_networks-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Anonymous_communication_devices" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Anonymous_communication_devices"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.5</span> <span>Anonymous communication devices</span> </div> </a> <ul id="toc-Anonymous_communication_devices-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Methods_used_to_"break"_security" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Methods_used_to_"break"_security"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Methods used to "break" security</span> </div> </a> <button aria-controls="toc-Methods_used_to_"break"_security-sublist" class="cdx-button cdx-button--weight-quiet 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href="#Laser_audio_surveillance"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.3</span> <span>Laser audio surveillance</span> </div> </a> <ul id="toc-Laser_audio_surveillance-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Systems_offering_partial_security" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Systems_offering_partial_security"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Systems offering partial security</span> </div> </a> <button aria-controls="toc-Systems_offering_partial_security-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Systems offering partial security subsection</span> </button> <ul id="toc-Systems_offering_partial_security-sublist" class="vector-toc-list"> <li id="toc-Cellphones" class="vector-toc-list-item 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href="#Programs_offering_more_security"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.4</span> <span>Programs offering more security</span> </div> </a> <ul id="toc-Programs_offering_more_security-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Criminal_use" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Criminal_use"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Criminal use</span> </div> </a> <ul id="toc-Criminal_use-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>See also</span> </div> </a> <button aria-controls="toc-See_also-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span 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<h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Secure communication</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. 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href="https://fa.wikipedia.org/wiki/%D8%A7%D8%B1%D8%AA%D8%A8%D8%A7%D8%B7_%D8%A7%D9%85%D9%86" title="ارتباط امن – Persian" lang="fa" hreflang="fa" data-title="ارتباط امن" 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/Communication_s%C3%A9curis%C3%A9e" title="Communication sécurisée – French" lang="fr" hreflang="fr" data-title="Communication sécurisée" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EB%B3%B4%EC%95%88_%ED%86%B5%EC%8B%A0" title="보안 통신 – Korean" lang="ko" hreflang="ko" data-title="보안 통신" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E3%82%BB%E3%82%AD%E3%83%A5%E3%82%A2%E9%80%9A%E4%BF%A1" title="セキュア通信 – Japanese" lang="ja" hreflang="ja" data-title="セキュア通信" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-sq mw-list-item"><a href="https://sq.wikipedia.org/wiki/Komunikimi_i_sigurt%C3%AB" title="Komunikimi i sigurtë – Albanian" lang="sq" hreflang="sq" data-title="Komunikimi i sigurtë" data-language-autonym="Shqip" data-language-local-name="Albanian" class="interlanguage-link-target"><span>Shqip</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/S%C3%A4ker_kommunikation" title="Säker kommunikation – Swedish" lang="sv" hreflang="sv" data-title="Säker kommunikation" data-language-autonym="Svenska" data-language-local-name="Swedish" 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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="box-Essay-like plainlinks metadata ambox ambox-style ambox-essay-like" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/40px-Edit-clear.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/60px-Edit-clear.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/80px-Edit-clear.svg.png 2x" data-file-width="48" data-file-height="48" /></span></span></div></td><td class="mbox-text"><div class="mbox-text-span">This article <b>is written like a <a href="/wiki/Wikipedia:What_Wikipedia_is_not#Wikipedia_is_not_a_publisher_of_original_thought" title="Wikipedia:What Wikipedia is not">personal reflection, personal essay, or argumentative essay</a></b> that states a Wikipedia editor's personal feelings or presents an original argument about a topic.<span class="hide-when-compact"> Please <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Secure_communication&action=edit">help improve it</a> by rewriting it in an <a href="/wiki/Wikipedia:Writing_better_articles#Information_style_and_tone" title="Wikipedia:Writing better articles">encyclopedic style</a>.</span> <span class="date-container"><i>(<span class="date">January 2015</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <p><b>Secure communication</b> is when two entities are communicating and do not want a third party to listen in. For this to be the case, the entities need to communicate in a way that is unsusceptible to <a href="/wiki/Eavesdropping" title="Eavesdropping">eavesdropping</a> or <a href="/wiki/Signals_intelligence" title="Signals intelligence">interception</a>.<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><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> Secure communication includes means by which people can share information with varying degrees of certainty that third parties cannot intercept what is said. Other than spoken face-to-face communication with no possible eavesdropper, it is probable that no communication is guaranteed to be secure in this sense, although practical obstacles such as legislation, resources, technical issues (interception and <a href="/wiki/Encryption" title="Encryption">encryption</a>), and the sheer volume of communication serve to limit <a href="/wiki/Surveillance" title="Surveillance">surveillance</a>. </p><p>With many communications taking place over long distance and mediated by technology, and increasing awareness of the importance of interception issues, technology and its compromise are at the heart of this debate. For this reason, this article focuses on communications mediated or intercepted by technology. </p><p>Also see <i><a href="/wiki/Trusted_Computing" title="Trusted Computing">Trusted Computing</a></i>, an approach under present development that achieves security in general at the potential cost of compelling obligatory trust in corporate and government bodies. </p> <meta property="mw:PageProp/toc" /> <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_communication&action=edit&section=1" title="Edit section: History"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In 1898, <a href="/wiki/Nikola_Tesla" title="Nikola Tesla">Nikola Tesla</a> demonstrated a <a href="/wiki/Radio_controlled" class="mw-redirect" title="Radio controlled">radio controlled</a> boat in <a href="/wiki/Madison_Square_Garden" title="Madison Square Garden">Madison Square Garden</a> that allowed secure communication between <a href="/wiki/Transmitter" title="Transmitter">transmitter</a> and <a href="/wiki/Radio_receiver" title="Radio receiver">receiver</a>.<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> </p><p>One of the most famous systems of secure communication was the <a href="/wiki/SIGSALY" title="SIGSALY">Green Hornet</a>. During WWII, <a href="/wiki/Winston_Churchill" title="Winston Churchill">Winston Churchill</a> had to discuss vital matters with <a href="/wiki/Franklin_D._Roosevelt" title="Franklin D. Roosevelt">Franklin D. Roosevelt</a>. In the beginning, the calls were made using a voice scrambler, as this was thought to be secure. When this was found to be untrue, engineers started to work on a whole new system, which resulted in the Green Hornet or <a href="/wiki/SIGSALY" title="SIGSALY">SIGSALY</a>. With the Green Hornet, any unauthorized party listening in would just hear <a href="/wiki/White_noise" title="White noise">white noise</a>, but the conversation would remain clear to authorized parties. As secrecy was paramount, the location of the Green Hornet was only known by the people who built it and Winston Churchill. To maintain secrecy, the Green Hornet was kept in a closet labeled 'Broom Cupboard.'' The Green Hornet used a <a href="/wiki/One-time_pad" title="One-time pad">one-time pad</a>. SIGSALY was also never broken.<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> </p> <div class="mw-heading mw-heading2"><h2 id="Nature_and_limits_of_security">Nature and limits of security</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=2" title="Edit section: Nature and limits of security"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Types_of_security">Types of security</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=3" title="Edit section: Types of security"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Security can be broadly categorized under the following headings, with examples: </p> <ul><li>Hiding the content or nature of a communication <ul><li><a href="/wiki/Code" title="Code">Code</a> – a rule to convert a piece of information (for example, a letter, word, phrase, or gesture) into another form or representation (one sign into another sign), not necessarily of the same type. In communications and information processing, encoding is the process by which information from a source is converted into symbols to be communicated. Decoding is the reverse process, converting these code symbols back into information understandable by a receiver. One reason for coding is to enable communication in places where ordinary spoken or written language is difficult or impossible. For example, semaphore, where the configuration of flags held by a signaler or the arms of a <a href="/wiki/Semaphore_line" class="mw-redirect" title="Semaphore line">semaphore tower</a> encodes parts of the message, typically individual letters and numbers. Another person standing a great distance away can interpret the flags and reproduce the words sent.</li> <li><a href="/wiki/Obfuscation" title="Obfuscation">Obfuscation</a></li> <li><a href="/wiki/Encryption" title="Encryption">Encryption</a></li> <li><a href="/wiki/Steganography" title="Steganography">Steganography</a></li> <li><a href="/wiki/Identity-based_security" title="Identity-based security">Identity Based</a></li></ul></li> <li>Hiding the parties to a communication – preventing identification, promoting <a href="/wiki/Anonymity" title="Anonymity">anonymity</a> <ul><li>"<a href="/wiki/Crowds_(anonymity_network)" title="Crowds (anonymity network)">Crowds</a>" and similar anonymous group structures – it is difficult to identify who said what when it comes from a "crowd"</li> <li>Anonymous communication devices – <a href="/wiki/Prepaid_mobile_phone#Privacy_rights" title="Prepaid mobile phone">unregistered cellphones</a>, <a href="/wiki/Internet_cafe" class="mw-redirect" title="Internet cafe">Internet cafes</a></li> <li><a href="/wiki/Anonymous_proxies" class="mw-redirect" title="Anonymous proxies">Anonymous proxies</a></li> <li>Hard-to-trace <a href="/wiki/Routing" title="Routing">routing</a> methods – through unauthorized third-party systems, or relays</li></ul></li> <li>Hiding the fact that a communication takes place <ul><li>"Security by obscurity" – similar to needle in a haystack</li> <li>Random traffic – creating random data flow to make the presence of genuine communication harder to detect and <a href="/wiki/Traffic_analysis" title="Traffic analysis">traffic analysis</a> less reliable</li></ul></li></ul> <p>Each of the three types of security is important, and depending on the circumstances, any of these may be critical. For example, if a communication is not readily identifiable, then it is unlikely to attract attention for identification of parties, and the mere fact a communication has taken place (regardless of content) is often enough by itself to establish an evidential link in legal prosecutions. It is also important with computers, to be sure where the security is applied, and what is covered. </p> <div class="mw-heading mw-heading2"><h2 id="Borderline_cases">Borderline cases</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=4" title="Edit section: Borderline cases"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A further category, which touches upon secure communication, is software intended to take advantage of security openings at the end-points. This software category includes <a href="/wiki/Trojan_horse_(computing)" title="Trojan horse (computing)">trojan horses</a>, <a href="/wiki/Keystroke_logging" title="Keystroke logging">keyloggers</a> and other <a href="/wiki/Spyware" title="Spyware">spyware</a>. </p><p>These types of activity are usually addressed with everyday mainstream security methods, such as <a href="/wiki/Antivirus" class="mw-redirect" title="Antivirus">antivirus</a> software, <a href="/wiki/Firewall_(computing)" title="Firewall (computing)">firewalls</a>, programs that identify or neutralize <a href="/wiki/Adware" title="Adware">adware</a> and <a href="/wiki/Spyware" title="Spyware">spyware</a>, and web filtering programs such as <a href="/wiki/Proxomitron" title="Proxomitron">Proxomitron</a> and <a href="/wiki/Privoxy" title="Privoxy">Privoxy</a> which check all web pages being read and identify and remove common nuisances contained. As a rule they fall under <a href="/wiki/Computer_security" title="Computer security">computer security</a> rather than secure communications. </p> <div class="mw-heading mw-heading2"><h2 id="Tools_used_to_obtain_security">Tools used to obtain security</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=5" title="Edit section: Tools used to obtain security"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Encryption">Encryption</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=6" title="Edit section: Encryption"><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/Encryption" title="Encryption">Encryption</a></div> <p><a href="/wiki/Encryption" title="Encryption">Encryption</a> is a method in which data is rendered hard to read by an unauthorized party. Since encryption methods are created to be extremely hard to break, many communication methods either use deliberately weaker encryption than possible, or have <a href="/wiki/Backdoor_(computing)" title="Backdoor (computing)">backdoors</a> inserted to permit rapid decryption. In some cases government authorities have required backdoors be installed in secret. Many methods of encryption are also subject to "<a href="/wiki/Man-in-the-middle_attack" title="Man-in-the-middle attack">man in the middle</a>" attack whereby a third party who can 'see' the establishment of the secure communication is made privy to the encryption method, this would apply for example to the interception of computer use at an ISP. Provided it is correctly programmed, sufficiently powerful, and the keys not intercepted, encryption would usually be considered secure. The article on <a href="/wiki/Key_size" title="Key size">key size</a> examines the key requirements for certain degrees of encryption security. </p><p>Encryption can be implemented in a way that requires the use of encryption, i.e. if encrypted communication is impossible then no traffic is sent, or opportunistically. <a href="/wiki/Opportunistic_encryption" title="Opportunistic encryption">Opportunistic encryption</a> is a lower security method to generally increase the percentage of generic traffic which is encrypted. This is analogous to beginning every conversation with "Do you speak <a href="/wiki/Code_talker" title="Code talker">Navajo</a>?" If the response is affirmative, then the conversation proceeds in Navajo, otherwise it uses the common language of the two speakers. This method does not generally provide <a href="/wiki/Authentication" title="Authentication">authentication</a> or <a href="/wiki/Anonymity" title="Anonymity">anonymity</a> but it does protect the content of the conversation from <a href="/wiki/Eavesdropping" title="Eavesdropping">eavesdropping</a>. </p><p>An <a href="/wiki/Information-theoretic_security" title="Information-theoretic security">Information-theoretic security</a> technique known as <a href="/wiki/Information-theoretic_security#Physical_Layer_Encryption" title="Information-theoretic security">physical layer encryption</a> ensures that a wireless communication link is provably secure with communications and coding techniques. </p> <div class="mw-heading mw-heading3"><h3 id="Steganography">Steganography</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=7" title="Edit section: Steganography"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Steganography" title="Steganography">Steganography</a></div> <p><a href="/wiki/Steganography" title="Steganography">Steganography</a> ("hidden writing") is the means by which data can be hidden within other more innocuous data. Thus a watermark proving ownership embedded in the data of a picture, in such a way it is hard to find or remove unless you know how to find it. Or, for communication, the hiding of important data (such as a telephone number) in apparently innocuous data (an MP3 music file). An advantage of steganography is <a href="/wiki/Plausible_deniability" title="Plausible deniability">plausible deniability</a>, that is, unless one can prove the data is there (which is usually not easy), it is deniable that the file contains any. </p> <div class="mw-heading mw-heading3"><h3 id="Identity-based_networks">Identity-based networks</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=8" title="Edit section: Identity-based networks"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Unwanted or malicious activities are possible on the web since the internet is effectively anonymous. True identity-based networks replace the ability to remain anonymous and are inherently more trustworthy since the identity of the sender and recipient are known. (The telephone system is an example of an identity-based network.) </p> <div class="mw-heading mw-heading3"><h3 id="Anonymized_networks">Anonymized networks</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=9" title="Edit section: Anonymized networks"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Recently, anonymous networking has been used to secure communications. In principle, a large number of users running the same system, can have communications routed between them in such a way that it is very difficult to detect what the complete message is, which user sent it, and where it is ultimately coming from or going to. Examples are <a href="/wiki/Crowds" class="mw-redirect" title="Crowds">Crowds</a>, <a href="/wiki/Tor_(anonymity_network)" class="mw-redirect" title="Tor (anonymity network)">Tor</a>, <a href="/wiki/I2P" title="I2P">I2P</a>, <a href="/wiki/Mixminion" title="Mixminion">Mixminion</a>, various <a href="/wiki/Anonymous_P2P" title="Anonymous P2P">anonymous P2P</a> networks, and others. </p> <div class="mw-heading mw-heading3"><h3 id="Anonymous_communication_devices">Anonymous communication devices</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=10" title="Edit section: Anonymous communication devices"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Typically, an unknown device would not be noticed, since so many other devices are in use. This is not assured in reality, due to the presence of systems such as <a href="/wiki/Carnivore_(FBI)" class="mw-redirect" title="Carnivore (FBI)">Carnivore</a> and <a href="/w/index.php?title=UNZAK&action=edit&redlink=1" class="new" title="UNZAK (page does not exist)">unzak</a>, which can monitor communications over entire networks, and the fact that the far end may be monitored as before. Examples include <a href="/wiki/Payphone" title="Payphone">payphones</a>, <a href="/wiki/Internet_cafe" class="mw-redirect" title="Internet cafe">Internet cafe</a>, etc. </p> <div class="mw-heading mw-heading2"><h2 id="Methods_used_to_"break"_security"><span id="Methods_used_to_.22break.22_security"></span>Methods used to "break" security</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=11" title="Edit section: Methods used to "break" security"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Bugging">Bugging</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=12" title="Edit section: Bugging"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Covert_listening_device" title="Covert listening device">Covert listening device</a></div> <p>The placing covertly of monitoring and/or transmission devices either within the communication device, or in the premises concerned. </p> <div class="mw-heading mw-heading3"><h3 id="Computers_(general)"><span id="Computers_.28general.29"></span>Computers (general)</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=13" title="Edit section: Computers (general)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Computer_security" title="Computer security">Computer security</a></div> <p>Any security obtained from a computer is limited by the many ways it can be compromised – by hacking, <a href="/wiki/Keystroke_logging" title="Keystroke logging">keystroke logging</a>, <a href="/wiki/Backdoor_(computing)" title="Backdoor (computing)">backdoors</a>, or even in extreme cases by monitoring the tiny electrical signals given off by keyboard or monitors to reconstruct what is typed or seen (<a href="/wiki/Tempest_(codename)" title="Tempest (codename)">TEMPEST</a>, which is complex). </p> <div class="mw-heading mw-heading3"><h3 id="Laser_audio_surveillance">Laser audio surveillance</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=14" title="Edit section: Laser audio surveillance"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Laser_microphone" title="Laser microphone">Laser microphone</a></div> <p>Sounds, including speech, inside rooms can be sensed by bouncing a <a href="/wiki/Laser" title="Laser">laser</a> beam off a window of the room where a conversation is held, and detecting and decoding the vibrations in the glass caused by the <a href="/wiki/Sound_wave" class="mw-redirect" title="Sound wave">sound waves</a>.<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> </p> <div class="mw-heading mw-heading2"><h2 id="Systems_offering_partial_security">Systems offering partial security</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=15" title="Edit section: Systems offering partial security"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Cellphones">Cellphones</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=16" title="Edit section: Cellphones"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Cellphones can easily be obtained, but are also easily traced and "tapped". There is no (or only limited) encryption, the phones are traceable – often even when switched off<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (August 2009)">citation needed</span></a></i>]</sup> – since the phone and SIM card broadcast their International Mobile Subscriber Identity (<a href="/wiki/International_mobile_subscriber_identity" title="International mobile subscriber identity">IMSI</a>). It is possible for a cellphone company to turn on some cellphones when the user is unaware and use the microphone to listen in on you, and according to James Atkinson, a <a href="/wiki/Counter-surveillance" class="mw-redirect" title="Counter-surveillance">counter-surveillance</a> specialist cited in the same source, "Security-conscious corporate executives routinely remove the batteries from their cell phones" since many phones' software can be used "as-is", or modified, to enable transmission without user awareness and the user can be located within a small distance using signal <a href="/wiki/Triangulation" title="Triangulation">triangulation</a> and now using built in GPS features for newer models. Transceivers may also be defeated by <a href="/wiki/Radio_jamming" title="Radio jamming">jamming</a> or <a href="/wiki/Faraday_cage" title="Faraday cage">Faraday cage</a>. </p><p>Some cellphones (<a href="/wiki/Apple_Inc." title="Apple Inc.">Apple</a>'s <a href="/wiki/IPhone" title="IPhone">iPhone</a>, <a href="/wiki/Google" title="Google">Google</a>'s <a href="/wiki/Android_(operating_system)" title="Android (operating system)">Android</a>) track and store users' position information, so that movements for months or years can be determined by examining the phone.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p><p>The U.S. Government also has access to cellphone surveillance technologies, mostly applied for law enforcement.<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> </p> <div class="mw-heading mw-heading3"><h3 id="Landlines">Landlines</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=17" title="Edit section: Landlines"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Analogue landlines are not encrypted, it lends itself to being easily tapped. Such tapping requires physical access to the line which can be easily obtained from a number of places, e.g. the phone location, distribution points, cabinets and the exchange itself. Tapping a landline in this way can enable an attacker to make calls which appear to originate from the tapped line. </p> <div class="mw-heading mw-heading3"><h3 id="Anonymous_Internet">Anonymous Internet</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=18" title="Edit section: Anonymous Internet"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Anonymity" title="Anonymity">Anonymity</a></div> <p>Using a <a href="https://en.wiktionary.org/wiki/third-party" class="extiw" title="wikt:third-party">third party</a> system of any kind (payphone, Internet cafe) is often secure, however if that system is used to access known locations (a known email account or 3rd party) then it may be tapped at the far end, or noted, and this will remove any security benefit obtained. Some countries also impose mandatory registration of Internet cafe users. </p><p><a href="/wiki/Anonymous_proxy" title="Anonymous proxy">Anonymous proxies</a> are another common type of protection, which allow one to access the net via a third party (often in a different country) and make tracing difficult. Note that there is seldom any guarantee that the <a href="/wiki/Plaintext" title="Plaintext">plaintext</a> is not tappable, nor that the proxy does not keep its own records of users or entire dialogs. As a result, anonymous proxies are a generally useful tool but may not be as secure as other systems whose security can be better assured. Their most common use is to prevent a record of the originating <a href="/wiki/IP_address" title="IP address">IP</a>, or address, being left on the target site's own records. Typical anonymous proxies are found at both regular websites such as Anonymizer.com and spynot.com, and on proxy sites which maintain up to date lists of large numbers of temporary proxies in operation. </p><p>A recent development on this theme arises when wireless Internet connections ("<a href="/wiki/Wi-Fi" title="Wi-Fi">Wi-Fi</a>") are left in their unsecured state. The effect of this is that any person in range of the base unit can <a href="/wiki/Piggybacking_(Internet_access)" title="Piggybacking (Internet access)">piggyback</a> the connection – that is, use it without the owner being aware. Since many connections are left open in this manner, situations where piggybacking might arise (willful or unaware) have successfully led to a defense in some cases, since it makes it difficult to prove the owner of the connection was the downloader, or had knowledge of the use to which unknown others might be putting their connection. An example of this was the Tammie Marson case, where neighbours and anyone else might have been the culprit in the sharing of copyright files.<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> Conversely, in other cases, people deliberately seek out businesses and households with unsecured connections, for illicit and anonymous Internet usage, or simply to obtain free <a href="/wiki/Bandwidth_(computing)" title="Bandwidth (computing)">bandwidth</a>.<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> </p> <div class="mw-heading mw-heading3"><h3 id="Programs_offering_more_security">Programs offering more security</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=19" title="Edit section: Programs offering more security"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Comparison_of_instant_messaging_clients#Secure_messengers" class="mw-redirect" title="Comparison of instant messaging clients">Comparison of instant messaging clients § Secure messengers</a>, and <a href="/wiki/Comparison_of_VoIP_software#Secure_VoIP_software" title="Comparison of VoIP software">Comparison of VoIP software § Secure VoIP software</a></div> <ul><li><a href="/wiki/Secure_instant_messaging" class="mw-redirect" title="Secure instant messaging">Secure instant messaging</a> – Some instant messaging clients use <a href="/wiki/End-to-end_encryption" title="End-to-end encryption">end-to-end encryption</a> with <a href="/wiki/Forward_secrecy" title="Forward secrecy">forward secrecy</a> to secure all instant messages to other users of the same software. Some instant messaging clients also offer end-to-end encrypted file transfer support and group messaging.</li> <li><a href="/wiki/VoIP" class="mw-redirect" title="VoIP">VoIP</a> – Some VoIP clients implement <a href="/wiki/ZRTP" title="ZRTP">ZRTP</a> and <a href="/wiki/Secure_Real-time_Transport_Protocol" title="Secure Real-time Transport Protocol">SRTP</a> encryption for calls.</li> <li><a href="/wiki/Secure_email" class="mw-redirect" title="Secure email">Secure email</a> – some email networks are designed to provide encrypted and/or anonymous communication. They authenticate and encrypt on the users own computer, to prevent transmission of plain text, and mask the sender and recipient. <a href="/wiki/Mixminion" title="Mixminion">Mixminion</a> and <a href="/wiki/I2P#I2P-Bote" title="I2P">I2P-Bote</a> provide a higher level of anonymity by using a network of anonymizing intermediaries, similar to how <a href="/wiki/Tor_(anonymity_network)" class="mw-redirect" title="Tor (anonymity network)">Tor</a> works, but at a higher latency.</li> <li><a href="/wiki/IRC" title="IRC">IRC</a> and web chat – Some IRC clients and systems use client-to-server encryption such as <a href="/wiki/Secure_Sockets_Layer" class="mw-redirect" title="Secure Sockets Layer">SSL</a>/<a href="/wiki/Transport_Layer_Security" title="Transport Layer Security">TLS</a>. This is not standardized.</li></ul> <div class="mw-heading mw-heading2"><h2 id="Criminal_use">Criminal use</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=20" title="Edit section: Criminal use"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Several secure communications networks, which were predominantly used by criminals, have been shut down by law enforcement agencies, including: <a href="/wiki/EncroChat" title="EncroChat">EncroChat</a>, <a href="/wiki/Sky_Global" class="mw-redirect" title="Sky Global">Sky Global / Sky ECC</a>, and <a href="/wiki/Phantom_Secure" title="Phantom Secure">Phantom Secure</a>. </p><p>In September 2024 Eurojust, Europol, and law enforcement agencies from a number of countries took down a secure communication service used for organized crime. The encryption network was operated by equipment and personnel in Sweden, Ireland, the Netherlands, France, Spain, Italy, Australia, and Canada.<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> </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_communication&action=edit&section=21" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="General_background">General background</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=22" title="Edit section: General background"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Computer_security" title="Computer security">Computer security</a></li> <li><a href="/wiki/Opportunistic_encryption" title="Opportunistic encryption">Opportunistic encryption</a></li> <li><a href="/wiki/Communications_security" title="Communications security">Communications security</a></li> <li><a href="/wiki/Secure_messaging" title="Secure messaging">Secure messaging</a></li></ul> <div class="mw-heading mw-heading3"><h3 id="Software_selections_and_comparisons">Software selections and comparisons</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=23" title="Edit section: Software selections and comparisons"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Comparison_of_VoIP_software" title="Comparison of VoIP software">Comparison of VoIP software</a></li> <li><a href="/wiki/Comparison_of_instant_messaging_clients" class="mw-redirect" title="Comparison of instant messaging clients">Comparison of instant messaging clients</a></li> <li><a href="/wiki/Anonymous_P2P" title="Anonymous P2P">Anonymous P2P</a></li></ul> <div class="mw-heading mw-heading3"><h3 id="Other">Other</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Secure_communication&action=edit&section=24" title="Edit section: Other"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Freenet" class="mw-redirect" title="Freenet">Freenet</a></li> <li><a href="/wiki/Hepting_vs._AT%26T" class="mw-redirect" title="Hepting vs. AT&T">Hepting vs. AT&T</a>, a 2006 lawsuit in which the <a href="/wiki/Electronic_Frontier_Foundation" title="Electronic Frontier Foundation">Electronic Frontier Foundation</a> alleges <a href="/wiki/AT%26T_Inc." class="mw-redirect" title="AT&T Inc.">AT&T Inc.</a> allowed the <a href="/wiki/NSA" class="mw-redirect" title="NSA">NSA</a> to tap all of its clients' Internet and <a href="/wiki/Voice_over_IP" title="Voice over IP">Voice over IP</a> communications</li> <li><a href="/wiki/NSA_warrantless_surveillance_controversy" class="mw-redirect" title="NSA warrantless surveillance controversy">NSA warrantless surveillance controversy</a></li> <li><a href="/wiki/Secret_cell_phone" class="mw-redirect" title="Secret cell phone">Secret cell phone</a></li> <li><a href="/wiki/Unode" title="Unode">Unode</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_communication&action=edit&section=25" 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 .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><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">D. P. Agrawal and Q-A. Zeng, <i>Introduction to Wireless and Mobile Systems</i> (2nd Edition, published by Thomson, April 2005) <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><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-534-49303-5" title="Special:BookSources/978-0-534-49303-5">978-0-534-49303-5</a></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">J.K. and K. Ross, <i>Computer Networking</i> (2nd Ed, Addison Wesley, 2003) <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-321-17644-8" title="Special:BookSources/978-0-321-17644-8">978-0-321-17644-8</a></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">The schematics are illustrated in <span><a rel="nofollow" class="external text" href="https://patents.google.com/patent/US613809">U.S. patent 613,809</a></span> and describes "rotating <a href="/wiki/Coherer" title="Coherer">coherers</a>".</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="CITEREFBauer2017" class="citation cs2">Bauer, Craig (2017), <a rel="nofollow" class="external text" href="https://dx.doi.org/10.1007/978-3-319-53280-6_7"><i>The Early History of Voice Encryption</i></a>, Boston Studies in the Philosophy and History of Science, vol. 324, Cham: Springer International Publishing, pp. 159–187, <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%2F978-3-319-53280-6_7">10.1007/978-3-319-53280-6_7</a>, <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-319-53278-3" title="Special:BookSources/978-3-319-53278-3"><bdi>978-3-319-53278-3</bdi></a><span class="reference-accessdate">, retrieved <span class="nowrap">2021-10-23</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Early+History+of+Voice+Encryption&rft.place=Cham&rft.series=Boston+Studies+in+the+Philosophy+and+History+of+Science&rft.pages=159-187&rft.pub=Springer+International+Publishing&rft.date=2017&rft_id=info%3Adoi%2F10.1007%2F978-3-319-53280-6_7&rft.isbn=978-3-319-53278-3&rft.aulast=Bauer&rft.aufirst=Craig&rft_id=http%3A%2F%2Fdx.doi.org%2F10.1007%2F978-3-319-53280-6_7&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+communication" 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 class="citation web cs1"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=mgAAAAAAMBAJ&pg=PA48">"High-tech bugging techniques, and a costly fix"</a>. <i>Popular Science</i>. August 1987.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Popular+Science&rft.atitle=High-tech+bugging+techniques%2C+and+a+costly+fix&rft.date=1987-08&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DmgAAAAAAMBAJ%26pg%3DPA48&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+communication" 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"><a rel="nofollow" class="external text" href="https://online.wsj.com/community/groups/question-day-229/topics/how-concerned-you-iphone-tracks?commentid=2388220">Wall Street Journal: How concerned are you that the iPhone tracks and stores your location?</a></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">Pell, Stephanie K., and Christopher Soghoian. 2014. "Your secret stingray's no secret anymore: The vanishing government monopoly over cell phone surveillance and its impact on national security and consumer privacy." <i>Harv. JL & Tech</i> 28(1).</span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.theregister.co.uk/2007/04/25/open_wi-fi_child_porn_case/">Open Wi-Fi proves no defence in child porn case</a>, The Register</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"><a rel="nofollow" class="external text" href="https://www.theregister.co.uk/2007/12/11/piggybacking_arrest_made/">'Extortionist' turns Wi-Fi thief to cover tracks</a>, The Register</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://www.eurojust.europa.eu/news/51-arrests-wide-scale-operation-take-down-encrypted-communication-platform-used-organised-crime-groups">"51 arrests in wide-scale operation to take down encrypted communication platform used by organised crime groups | Eurojust | European Union Agency for Criminal Justice Cooperation"</a>. <i>www.eurojust.europa.eu</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2024-10-22</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.eurojust.europa.eu&rft.atitle=51+arrests+in+wide-scale+operation+to+take+down+encrypted+communication+platform+used+by+organised+crime+groups+%7C+Eurojust+%7C+European+Union+Agency+for+Criminal+Justice+Cooperation&rft_id=https%3A%2F%2Fwww.eurojust.europa.eu%2Fnews%2F51-arrests-wide-scale-operation-take-down-encrypted-communication-platform-used-organised-crime-groups&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASecure+communication" class="Z3988"></span></span> </li> </ol></div></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_communication&action=edit&section=26" title="Edit section: External links"><span>edit</span></a><span 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style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Apple_Mail" title="Apple Mail">Apple Mail</a></li> <li><a href="/wiki/Autocrypt" title="Autocrypt">Autocrypt</a></li> <li><a href="/wiki/Claws_Mail" title="Claws Mail">Claws Mail</a></li> <li><a href="/wiki/Enigmail" title="Enigmail">Enigmail</a></li> <li><a href="/wiki/GNU_Privacy_Guard" title="GNU Privacy Guard">GPG</a> (<a href="/wiki/Gpg4win" title="Gpg4win">Gpg4win</a>)</li> <li><a href="/wiki/Kontact" title="Kontact">Kontact</a></li> <li><a href="/wiki/Microsoft_Outlook" title="Microsoft Outlook">Outlook</a></li> <li><a href="/wiki/Pretty_Easy_privacy" title="Pretty Easy privacy">p≡p</a></li> <li><a href="/wiki/Pretty_Good_Privacy" title="Pretty Good Privacy">PGP</a></li> <li><a href="/wiki/Sylpheed" title="Sylpheed">Sylpheed</a></li> <li><a href="/wiki/Mozilla_Thunderbird" title="Mozilla Thunderbird">Thunderbird</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a class="mw-selflink selflink">Secure<br />communication</a></th><td class="navbox-list-with-group navbox-list navbox-odd" 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" style="width:1%"><a href="/wiki/Off-the-Record_Messaging" class="mw-redirect" title="Off-the-Record Messaging">OTR</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/Adium" title="Adium">Adium</a></li> <li><a href="/wiki/BitlBee" title="BitlBee">BitlBee</a></li> <li><a href="/wiki/Centericq" title="Centericq">Centericq</a></li> <li><a href="/wiki/ChatSecure" title="ChatSecure">ChatSecure</a></li> <li><a href="/wiki/Climm" title="Climm">climm</a></li> <li><a href="/wiki/Jitsi" title="Jitsi">Jitsi</a></li> <li><a href="/wiki/Kopete" title="Kopete">Kopete</a></li> <li><a href="/wiki/Profanity_(instant_messaging_client)" title="Profanity (instant messaging client)">Profanity</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Secure_Shell" title="Secure Shell">SSH</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/Dropbear_(software)" title="Dropbear (software)">Dropbear</a></li> <li><a href="/wiki/Lsh" title="Lsh">lsh</a></li> <li><a href="/wiki/OpenSSH" title="OpenSSH">OpenSSH</a></li> <li><a href="/wiki/PuTTY" title="PuTTY">PuTTY</a></li> <li><a href="/wiki/SecureCRT" title="SecureCRT">SecureCRT</a></li> <li><a href="/wiki/WinSCP" title="WinSCP">WinSCP</a></li> <li><a href="/wiki/WolfSSH" title="WolfSSH">wolfSSH</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Transport_Layer_Security" title="Transport Layer Security">TLS & SSL</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/BBM_Enterprise" title="BBM Enterprise">BBM Enterprise</a></li> <li><a href="/wiki/Bouncy_Castle_(cryptography)" title="Bouncy Castle (cryptography)">Bouncy Castle</a></li> <li><a href="/wiki/OpenSSL#BoringSSL" title="OpenSSL">BoringSSL</a></li> <li><a href="/wiki/Botan_(programming_library)" title="Botan (programming library)">Botan</a></li> <li><a href="/wiki/Cryptlib" title="Cryptlib">cryptlib</a></li> <li><a href="/wiki/GnuTLS" title="GnuTLS">GnuTLS</a></li> <li><a href="/wiki/Java_Secure_Socket_Extension" title="Java Secure Socket Extension">JSSE</a></li> <li><a href="/wiki/LibreSSL" title="LibreSSL">LibreSSL</a></li> <li><a href="/wiki/MatrixSSL" title="MatrixSSL">MatrixSSL</a></li> <li><a href="/wiki/Network_Security_Services" title="Network Security Services">NSS</a></li> <li><a href="/wiki/OpenSSL" title="OpenSSL">OpenSSL</a></li> <li><a href="/wiki/Mbed_TLS" title="Mbed TLS">mbed TLS</a></li> <li><a href="/wiki/BSAFE" title="BSAFE">BSAFE</a></li> <li><a href="/wiki/Security_Support_Provider_Interface" title="Security Support Provider Interface">SChannel</a></li> <li><a href="/wiki/SSLeay" title="SSLeay">SSLeay</a></li> <li><a href="/wiki/Stunnel" title="Stunnel">stunnel</a></li> <li><a href="/wiki/TeamNote" title="TeamNote">TeamNote</a></li> <li><a href="/wiki/WolfSSL" title="WolfSSL">wolfSSL</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Virtual_private_network" title="Virtual private network">VPN</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/Check_Point_VPN-1" class="mw-redirect" title="Check Point VPN-1">Check Point VPN-1</a></li> <li><a href="/wiki/LogMeIn_Hamachi" title="LogMeIn Hamachi">Hamachi</a></li> <li><a href="/wiki/Openswan" title="Openswan">Openswan</a></li> <li><a href="/wiki/OpenVPN" title="OpenVPN">OpenVPN</a></li> <li><a href="/wiki/SoftEther_VPN" title="SoftEther VPN">SoftEther VPN</a></li> <li><a href="/wiki/StrongSwan" title="StrongSwan">strongSwan</a></li> <li><a href="/wiki/Tinc_(protocol)" title="Tinc (protocol)">Tinc</a></li> <li><a href="/wiki/WireGuard" title="WireGuard">WireGuard</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/ZRTP" title="ZRTP">ZRTP</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/Jitsi" title="Jitsi">Jitsi</a></li> <li><a href="/wiki/Linphone" title="Linphone">Linphone</a></li> <li><a href="/wiki/Jami_(software)" title="Jami (software)">Jami</a></li> <li><a href="/wiki/Zfone" title="Zfone">Zfone</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Peer-to-peer" title="Peer-to-peer">P2P</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/Bitmessage" title="Bitmessage">Bitmessage</a></li> <li><a href="/wiki/Briar_(software)" title="Briar (software)">Briar</a></li> <li><a href="/wiki/RetroShare" class="mw-redirect" title="RetroShare">RetroShare</a></li> <li><a href="/wiki/Tox_(protocol)" title="Tox (protocol)">Tox</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Double_Ratchet_Algorithm" title="Double Ratchet Algorithm">DRA</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/Matrix_(protocol)" title="Matrix (protocol)">Matrix</a></li> <li><a href="/wiki/OMEMO" title="OMEMO">OMEMO</a> <ul><li><a href="/wiki/Cryptocat" title="Cryptocat">Cryptocat</a></li> <li><a href="/wiki/ChatSecure" title="ChatSecure">ChatSecure</a></li></ul></li> <li><a href="/wiki/Wire_Swiss" title="Wire Swiss">Proteus</a></li> <li><a href="/wiki/Session_(software)" title="Session (software)">Session</a></li> <li><a href="/wiki/Signal_Protocol" title="Signal Protocol">Signal Protocol</a> <ul><li><a href="/wiki/Facebook_Messenger" class="mw-redirect" title="Facebook Messenger">Facebook Messenger</a></li> <li><a href="/wiki/Google_Allo" title="Google Allo">Google Allo</a></li> <li><a href="/wiki/Google_Messages" title="Google Messages">Google Messages</a></li> <li><a href="/wiki/Signal_(messaging_app)" class="mw-redirect" title="Signal (messaging app)">Signal</a></li> <li><a href="/wiki/TextSecure" title="TextSecure">TextSecure</a></li> <li><a href="/wiki/WhatsApp" title="WhatsApp">WhatsApp</a></li></ul></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Disk_encryption" title="Disk encryption">Disk encryption</a><br /><span style="font-weight:normal">(<a href="/wiki/Comparison_of_disk_encryption_software" title="Comparison of disk encryption software">Comparison</a>)</span></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/BestCrypt" title="BestCrypt">BestCrypt</a></li> <li><a href="/wiki/BitLocker" title="BitLocker">BitLocker</a></li> <li><a href="/wiki/CrossCrypt" title="CrossCrypt">CrossCrypt</a></li> <li><a href="/wiki/Cryptoloop" title="Cryptoloop">Cryptoloop</a></li> <li><a href="/wiki/Dm-crypt" title="Dm-crypt">dm-crypt</a></li> <li><a href="/wiki/DriveSentry" title="DriveSentry">DriveSentry</a></li> <li><a href="/wiki/E4M" title="E4M">E4M</a></li> <li><a href="/wiki/ECryptfs" title="ECryptfs">eCryptfs</a></li> <li><a href="/wiki/FileVault" title="FileVault">FileVault</a></li> <li><a href="/wiki/FreeOTFE" title="FreeOTFE">FreeOTFE</a></li> <li><a href="/wiki/GBDE" title="GBDE">GBDE</a></li> <li><a href="/wiki/Geli_(software)" title="Geli (software)">geli</a></li> <li><a href="/wiki/Linux_Unified_Key_Setup" title="Linux Unified Key Setup">LUKS</a></li> <li><a href="/wiki/PGPDisk" title="PGPDisk">PGPDisk</a></li> <li><a href="/wiki/Private_Disk" title="Private Disk">Private Disk</a></li> <li><a href="/wiki/Scramdisk" title="Scramdisk">Scramdisk</a></li> <li><a href="/wiki/Sentry_2020" title="Sentry 2020">Sentry 2020</a></li> <li><a href="/wiki/TrueCrypt" title="TrueCrypt">TrueCrypt</a> <ul><li><a href="/wiki/TrueCrypt_version_history" title="TrueCrypt version history">History</a></li></ul></li> <li><a href="/wiki/VeraCrypt" title="VeraCrypt">VeraCrypt</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Anonymity#Anonymity_on_the_Internet" title="Anonymity">Anonymity</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/GNUnet#File_sharing" title="GNUnet">GNUnet</a></li> <li><a href="/wiki/I2P" title="I2P">I2P</a></li> <li><a href="/wiki/Java_Anon_Proxy" title="Java Anon Proxy">Java Anon Proxy</a></li> <li><a href="/wiki/Tor_(network)" title="Tor (network)">Tor</a></li> <li><a href="/wiki/Vidalia_(software)" title="Vidalia (software)">Vidalia</a></li> <li><a href="/wiki/RetroShare" class="mw-redirect" title="RetroShare">RetroShare</a></li> <li><a href="/wiki/Ricochet_(software)" title="Ricochet (software)">Ricochet</a></li> <li><a href="/wiki/Wickr" title="Wickr">Wickr</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/File_system" title="File system">File systems</a> <span style="font-weight:normal">(<a href="/wiki/List_of_cryptographic_file_systems" title="List of cryptographic file systems">List</a>)</span></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/EncFS" title="EncFS">EncFS</a></li> <li><a href="/wiki/Encrypting_File_System" title="Encrypting File System">EFS</a></li> <li><a href="/wiki/ECryptfs" title="ECryptfs">eCryptfs</a></li> <li><a href="/wiki/Linux_Unified_Key_Setup" title="Linux Unified Key Setup">LUKS</a></li> <li><a href="/w/index.php?title=PEFS&action=edit&redlink=1" class="new" title="PEFS (page does not exist)">PEFS</a></li> <li><a href="/wiki/Rubberhose_(file_system)" class="mw-redirect" title="Rubberhose (file system)">Rubberhose</a></li> <li><a href="/wiki/StegFS" title="StegFS">StegFS</a></li> <li><a href="/wiki/Tahoe-LAFS" title="Tahoe-LAFS">Tahoe-LAFS</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Security-focused_operating_system" title="Security-focused operating system">Security-focused<br />operating system</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/Tails_(operating_system)" title="Tails (operating system)">Tails</a></li> <li><a href="/wiki/Qubes" class="mw-redirect" title="Qubes">Qubes</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Service providers</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/Freenet" class="mw-redirect" title="Freenet">Freenet</a></li> <li><a href="/wiki/Tresorit" title="Tresorit">Tresorit</a></li> <li><a href="/wiki/Wuala" title="Wuala">Wuala</a></li> <li><a href="/wiki/NordLocker" title="NordLocker">NordLocker</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Educational</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/CrypTool" title="CrypTool">CrypTool</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Anti%E2%80%93computer_forensics" title="Anti–computer forensics">Anti–computer forensics</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/USBKill" title="USBKill">USBKill</a></li> <li><a href="/wiki/BusKill" title="BusKill">BusKill</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related topics</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/Outline_of_cryptography" title="Outline of cryptography">Outline of cryptography</a></li> <li><a href="/wiki/Timeline_of_cryptography" title="Timeline of cryptography">Timeline of cryptography</a></li> <li><a href="/wiki/Hash_function" title="Hash function">Hash functions</a> <ul><li><a href="/wiki/Cryptographic_hash_function" 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