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<title>Key (cryptography)</title>

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<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">Key (cryptography)</span></span>

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<p>A <b>key</b> in <a href="Cryptography" title="Cryptography">cryptography</a> is a piece of information, usually a string of numbers or letters that are stored in a file, which, when processed through a cryptographic <a href="Algorithm" title="Algorithm">algorithm</a>, can <a href="Encryption" title="Encryption">encode</a> or decode cryptographic data. Based on the used method, the key can be different sizes and varieties, but in all cases, the strength of the encryption relies on the security of the key being maintained. A key's <a href="Security_strength" class="mw-redirect" title="Security strength">security strength</a> is dependent on its algorithm, the size of the key, the generation of the key, and the process of key exchange.

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<div class="mw-heading mw-heading2"><h2 id="Scope">Scope</h2></div>

<p>The key is what is used to encrypt data from <a href="Plaintext" title="Plaintext">plaintext</a> to <a href="Ciphertext" title="Ciphertext">ciphertext</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> There are different methods for utilizing keys and encryption.

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<div class="mw-heading mw-heading3"><h3 id="Symmetric_cryptography">Symmetric cryptography</h3></div>

<p><a href="Symmetric_cryptography" class="mw-redirect" title="Symmetric cryptography">Symmetric cryptography</a> refers to the practice of the same key being used for both encryption and decryption.<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>

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<div class="mw-heading mw-heading3"><h3 id="Asymmetric_cryptography">Asymmetric cryptography</h3></div>

<p><a href="Asymmetric_cryptography" class="mw-redirect" title="Asymmetric cryptography">Asymmetric cryptography</a> has separate keys for encrypting and decrypting.<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><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> These keys are known as the public and private keys, respectively.<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>

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<div class="mw-heading mw-heading2"><h2 id="Purpose">Purpose</h2></div>

<p>Since the key protects the confidentiality and integrity of the system, it is important to be kept secret from unauthorized parties. With public key cryptography, only the private key must be kept secret, but with symmetric cryptography, it is important to maintain the confidentiality of the key. <a href="Kerckhoffs's_principle" title="Kerckhoffs's principle">Kerckhoff's principle</a> states that the entire security of the cryptographic system relies on the secrecy of the key.<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>

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<div class="mw-heading mw-heading2"><h2 id="Key_sizes">Key sizes</h2></div>

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</style><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Key_size" title="Key size">Key size</a></div>

<p><a href="Key_size" title="Key size">Key size</a> is the number of <a href="Bit" title="Bit">bits</a> in the key defined by the algorithm. This size defines the upper bound of the cryptographic algorithm's security.<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> The larger the key size, the longer it will take before the key is compromised by a brute force attack. Since perfect secrecy is not feasible for key algorithms, researches are now more focused on computational security.

</p><p>In the past, keys were required to be a minimum of 40 bits in length, however, as technology advanced, these keys were being broken quicker and quicker. As a response, restrictions on symmetric keys were enhanced to be greater in size.

</p><p>Currently, 2048 bit <a href="RSA_(cryptosystem)" class="mw-redirect" title="RSA (cryptosystem)">RSA</a><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> is commonly used, which is sufficient for current systems. However, current RSA key sizes would all be cracked quickly with a powerful quantum computer.<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><p>"The keys used in public key cryptography have some mathematical structure. For example, public keys used in the RSA system are the product of two prime numbers. Thus public key systems require longer key lengths than symmetric systems for an equivalent level of security. 3072 bits is the suggested key length for systems based on factoring and integer discrete logarithms which aim to have security equivalent to a 128 bit symmetric cipher."<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>

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<div class="mw-heading mw-heading2"><h2 id="Key_generation">Key generation</h2></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Key_generation" title="Key generation">Key generation</a></div>

<p>To prevent a key from being guessed, keys need to be generated randomly and contain sufficient <a href="Entropy_(information_theory)" title="Entropy (information theory)">entropy</a>. The problem of how to safely generate random keys is difficult and has been addressed in many ways by various cryptographic systems. A key can directly be generated by using the output of a Random Bit Generator (RBG), a system that generates a sequence of unpredictable and unbiased bits.<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> A RBG can be used to directly produce either a symmetric key or the random output for an asymmetric key pair generation. Alternatively, a key can also be indirectly created during a key-agreement transaction, from another key or from a password.<sup id="cite_ref-NIST_12-0" class="reference"><a href="#cite_note-NIST-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup>

</p><p>Some operating systems include tools for "collecting" entropy from the timing of unpredictable operations such as disk drive head movements. For the production of small amounts of keying material, ordinary dice provide a good source of high-quality randomness.

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<div class="mw-heading mw-heading2"><h2 id="Establishment_scheme">Establishment scheme</h2></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Key_exchange" title="Key exchange">Key exchange</a></div>

<p>The security of a key is dependent on how a key is exchanged between parties. Establishing a secured communication channel is necessary so that outsiders cannot obtain the key. A key establishment scheme (or key exchange) is used to transfer an encryption key among entities. Key agreement and key transport are the two types of a key exchange scheme that are used to be  remotely exchanged between entities . In a key agreement scheme, a secret key, which is used between the sender and the receiver to encrypt and decrypt information, is set up to be sent indirectly. All parties exchange information (the shared secret) that permits each party to derive the secret key material. In a key transport scheme, encrypted keying material that is chosen by the sender is transported to the receiver. Either symmetric key or asymmetric key techniques can be used in both schemes.<sup id="cite_ref-NIST_12-1" class="reference"><a href="#cite_note-NIST-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup>

</p><p>The <a href="Diffie%E2%80%93Hellman_key_exchange" title="Diffie–Hellman key exchange">Diffie–Hellman key exchange</a> and <a href="Rivest-Shamir-Adleman" class="mw-redirect" title="Rivest-Shamir-Adleman">Rivest-Shamir-Adleman</a> (RSA) are the most two widely used key exchange algorithms.<sup id="cite_ref-Yassein_etal_2017_13-0" class="reference"><a href="#cite_note-Yassein_etal_2017-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> In 1976, <a href="Whitfield_Diffie" title="Whitfield Diffie">Whitfield Diffie</a> and <a href="Martin_Hellman" title="Martin Hellman">Martin Hellman</a> constructed the <a href="Diffie%E2%80%93Hellman_key_exchange" title="Diffie–Hellman key exchange">Diffie–Hellman</a> algorithm, which was the first public key algorithm. The <a href="Diffie%E2%80%93Hellman_key_exchange" title="Diffie–Hellman key exchange">Diffie–Hellman</a> key exchange protocol allows key exchange over an insecure channel by electronically generating a shared key between two parties. On the other hand, <a href="Rivest%E2%80%93Shamir%E2%80%93Adleman" class="mw-redirect" title="Rivest–Shamir–Adleman">RSA</a> is a form of the asymmetric key system which consists of three steps: key generation, encryption, and decryption.<sup id="cite_ref-Yassein_etal_2017_13-1" class="reference"><a href="#cite_note-Yassein_etal_2017-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup>

</p><p>Key confirmation delivers an assurance between the key confirmation recipient and provider that the shared keying materials are correct and established. The <a href="National_Institute_of_Standards_and_Technology" title="National Institute of Standards and Technology">National Institute of Standards and Technology</a> recommends key confirmation to be integrated into a key establishment scheme to validate its implementations.<sup id="cite_ref-NIST_12-2" class="reference"><a href="#cite_note-NIST-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup>

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<div class="mw-heading mw-heading2"><h2 id="Management">Management</h2></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Key_management" title="Key management">Key management</a></div>

<p><a href="Key_management" title="Key management">Key management</a> concerns the generation, establishment, storage, usage and replacement of cryptographic keys. A <a href="Key_management" title="Key management">key management system</a> (KMS) typically includes three steps of establishing, storing and using keys. The base of security for the generation, storage, distribution, use and destruction of keys depends on successful key management protocols.<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>

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<div class="mw-heading mw-heading2"><h2 id="Key_vs_password">Key vs password</h2></div>

<p>A password is a memorized series of characters including letters, digits, and other special symbols that are used to verify identity. It is often produced by a human user or a password management software to protect personal and sensitive information or generate cryptographic keys. Passwords are often created to be memorized by users and may contain non-random information such as dictionary words.<sup id="cite_ref-NIST_12-3" class="reference"><a href="#cite_note-NIST-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> On the other hand, a key can help strengthen password protection by implementing a cryptographic algorithm which is difficult to guess or replace the password altogether. A key is generated based on random or pseudo-random data and can often be unreadable to humans.<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>

</p><p>A password is less safe than a cryptographic key due to its low entropy, randomness, and human-readable properties. However, the password may be the only secret data that is accessible to the cryptographic algorithm for <a href="Information_security" title="Information security">information security</a> in some applications such as securing information in storage devices. Thus, a deterministic algorithm called a <a href="Key_derivation_function" title="Key derivation function">key derivation function</a> (KDF) uses a password to generate the secure cryptographic keying material to compensate for the password's weakness. Various methods such as adding a <a href="Salt_(cryptography)" title="Salt (cryptography)">salt</a> or key stretching may be used in the generation.<sup id="cite_ref-NIST_12-4" class="reference"><a href="#cite_note-NIST-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup>

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<ul><li><a href="Cryptographic_key_types" title="Cryptographic key types">Cryptographic key types</a></li>

<li><a href="Diceware" title="Diceware">Diceware</a></li>

<li><a href="Group_key" title="Group key">Group key</a></li>

<li><a href="HMAC" title="HMAC">Keyed hash algorithm</a></li>

<li><a href="Key_authentication" title="Key authentication">Key authentication</a></li>

<li><a href="Key_derivation_function" title="Key derivation function">Key derivation function</a></li>

<li><a href="Key_distribution_center" title="Key distribution center">Key distribution center</a></li>

<li><a href="Key_escrow" title="Key escrow">Key escrow</a></li>

<li><a href="Key_exchange" title="Key exchange">Key exchange</a></li>

<li><a href="Key_generation" title="Key generation">Key generation</a></li>

<li><a href="Key_management" title="Key management">Key management</a></li>

<li><a href="Key_schedule" title="Key schedule">Key schedule</a></li>

<li><a href="Key_server_(cryptographic)" title="Key server (cryptographic)">Key server</a></li>

<li><a href="Key_signature_(cryptography)" title="Key signature (cryptography)">Key signature (cryptography)</a></li>

<li><a href="Key_signing_party" title="Key signing party">Key signing party</a></li>

<li><a href="Key_stretching" title="Key stretching">Key stretching</a></li>

<li><a href="Key-agreement_protocol" title="Key-agreement protocol">Key-agreement protocol</a></li>

<li><a href="List_of_cryptographic_key_types" class="mw-redirect" title="List of cryptographic key types">glossary</a></li>

<li><a href="Password_psychology" title="Password psychology">Password psychology</a></li>

<li><a href="Public_key_fingerprint" title="Public key fingerprint">Public key fingerprint</a></li>

<li><a href="Random_number_generator" class="mw-redirect" title="Random number generator">Random number generator</a></li>

<li><a href="Session_key" title="Session key">Session key</a></li>

<li><a href="Tripcode" class="mw-redirect" title="Tripcode">Tripcode</a></li>

<li><a href="Trusted_paper_key" class="mw-redirect" title="Trusted paper key">Machine-readable paper key</a></li>

</div>

<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>

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</style><cite id="CITEREFPiper2002" class="citation cs2">Piper, Fred (2002), <span class="id-lock-subscription" title="Paid subscription required"><a rel="nofollow" class="external text" href="https://onlinelibrary.wiley.com/doi/abs/10.1002/0471028959.sof070">"Cryptography"</a></span>, <i>Encyclopedia of Software Engineering</i>, American Cancer Society, <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2F0471028959.sof070">10.1002/0471028959.sof070</a>, <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-0-471-02895-6</bdi><span class="reference-accessdate">, retrieved <span class="nowrap">2021-04-09</span></span></cite></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"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.cloudflare.com/learning/ssl/what-is-a-cryptographic-key">"What is a cryptographic key? | Keys and SSL encryption"</a>.</cite></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"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.cs.cornell.edu/courses/cs5430/2013sp/TL04.asymmetric.html">"Asymmetric-Key Cryptography"</a>. <i>cs.cornell.edu</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2021-04-02</span></span>.</cite></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"><cite id="CITEREFChandraPairaAlamSanyal2014" class="citation book cs1">Chandra, S.; Paira, S.; Alam, S. S.; Sanyal, G. (2014). "A comparative survey of Symmetric and Asymmetric Key Cryptography". <i>2014 International Conference on Electronics, Communication and Computational Engineering (ICECCE)</i>. pp. <span class="nowrap">83–</span>93. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FICECCE.2014.7086640">10.1109/ICECCE.2014.7086640</a>. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-4799-5748-4</bdi>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:377667">377667</a>.</cite></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"><cite id="CITEREFKumarRagupathy2016" class="citation book cs1">Kumar, M. G. V.; Ragupathy, U. S. (March 2016). "A Survey on current key issues and status in cryptography". <i>2016 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET)</i>. pp. <span class="nowrap">205–</span>210. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FWiSPNET.2016.7566121">10.1109/WiSPNET.2016.7566121</a>. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-4673-9338-6</bdi>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:14794991">14794991</a>.</cite></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"><cite id="CITEREFMrdovicPerunicic2008" class="citation book cs1 cs1-prop-long-vol">Mrdovic, S.; Perunicic, B. (September 2008). "Kerckhoffs' principle for intrusion detection". <i>Networks 2008 - the 13th International Telecommunications Network Strategy and Planning Symposium</i>. Vol. Supplement. pp. <span class="nowrap">1–</span>8. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FNETWKS.2008.6231360">10.1109/NETWKS.2008.6231360</a>. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-963-8111-68-5</bdi>.</cite></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"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.techopedia.com/definition/3999/key-length">"What is Key Length? - Definition from Techopedia"</a>. <i>Techopedia.com</i>. 16 November 2011<span class="reference-accessdate">. Retrieved <span class="nowrap">2021-05-01</span></span>.</cite></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"><cite id="CITEREFHellman" class="citation journal cs1">Hellman, Martin. <a rel="nofollow" class="external text" href="https://netlab.ulusofona.pt/im/teoricas/OverviewPublicKeyCryptography.pdf">"An Overview of Public Key Cryptography"</a> <span class="cs1-format">(PDF)</span>. <i>IEEE Communications Magazine</i>.</cite></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"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://news.mit.edu/2024/toward-code-breaking-quantum-computer-0823">"Toward a code-breaking quantum computer"</a>. <i>MIT News | Massachusetts Institute of Technology</i>. 2024-08-23<span class="reference-accessdate">. Retrieved <span class="nowrap">2025-05-14</span></span>.</cite></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"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20230908035830/https://nakedsecurity.sophos.com/2013/05/27/anatomy-of-a-change-google-announces-it-will-double-its-ssl-key-sizes/">"Anatomy of a change – Google announces it will double its SSL key sizes"</a>. <i>Naked Security</i>. 2013-05-27. Archived from <a rel="nofollow" class="external text" href="https://nakedsecurity.sophos.com/2013/05/27/anatomy-of-a-change-google-announces-it-will-double-its-ssl-key-sizes/">the original</a> on 8 September 2023<span class="reference-accessdate">. Retrieved <span class="nowrap">2021-04-09</span></span>.</cite></span>

</li>

<li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><cite id="CITEREFDang2012" class="citation web cs1">Dang, Quynh (August 2012). <a rel="nofollow" class="external text" href="https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-107r1.pdf">"Recommendation for Applications Using Approved Hash Algorithms"</a> <span class="cs1-format">(PDF)</span><span class="reference-accessdate">. Retrieved <span class="nowrap">2021-04-02</span></span>.</cite></span>

</li>

<li id="cite_note-NIST-12"><span class="mw-cite-backlink">^ <a href="#cite_ref-NIST_12-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-NIST_12-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-NIST_12-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-NIST_12-3"><sup><i><b>d</b></i></sup></a> <a href="#cite_ref-NIST_12-4"><sup><i><b>e</b></i></sup></a></span> <span class="reference-text"><cite id="CITEREFTuranBarkerBurrChen2010" class="citation report cs1">Turan, M. S.; Barker, E. B.; Burr, W. E.; Chen, L. (2010). <a rel="nofollow" class="external text" href="https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-132.pdf">Recommendation for password-based key derivation</a> <span class="cs1-format">(PDF)</span> (Report). <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.6028%2FNIST.SP.800-132">10.6028/NIST.SP.800-132</a>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:56801929">56801929</a>.</cite></span>

</li>

<li id="cite_note-Yassein_etal_2017-13"><span class="mw-cite-backlink">^ <a href="#cite_ref-Yassein_etal_2017_13-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Yassein_etal_2017_13-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite id="CITEREFYasseinAljawarnehQawasmehMardini2017" class="citation book cs1">Yassein, M. B.; Aljawarneh, S.; Qawasmeh, E.; Mardini, W.; Khamayseh, Y. (2017). <a rel="nofollow" class="external text" href="https://ieeexplore.ieee.org/document/8308215/;jsessionid=aTy3qyMmnoiUUKufk8VEl4llW1jnhntWSm9CUa21rjkJ3qW3bths!861039390">"Comprehensive study of symmetric key and asymmetric key encryption algorithms"</a>. <i>2017 International Conference on Engineering and Technology (ICET)</i>. pp. <span class="nowrap">1–</span>7. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FICEngTechnol.2017.8308215">10.1109/ICEngTechnol.2017.8308215</a>. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-5386-1949-0</bdi>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:3781693">3781693</a>.</cite></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"><cite id="CITEREFBarker2016" class="citation web cs1">Barker, Elaine (January 2016). <a rel="nofollow" class="external text" href="https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-57pt1r4.pdf">"Recommendation for Key Management"</a> <span class="cs1-format">(PDF)</span><span class="reference-accessdate">. Retrieved <span class="nowrap">2021-04-02</span></span>.</cite></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"><cite id="CITEREFKhillar2020" class="citation web cs1">Khillar, Sagar (29 April 2020). <a rel="nofollow" class="external text" href="http://www.differencebetween.net/technology/difference-between-encryption-and-password-protection/">"Difference Between Encryption and Password Protection | Difference Between"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">2021-04-02</span></span>.</cite></span>

</li>

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<ul><li><a href="History_of_cryptography" title="History of cryptography">History of cryptography</a></li>

<li><a href="Outline_of_cryptography" title="Outline of cryptography">Outline of cryptography</a></li>

<li><a href="Classical_cipher" title="Classical cipher">Classical cipher</a></li>

<li><a href="Cryptographic_protocol" title="Cryptographic protocol">Cryptographic protocol</a>

<ul><li><a href="Authentication_protocol" title="Authentication protocol">Authentication protocol</a></li></ul></li>

<li><a href="Cryptographic_primitive" title="Cryptographic primitive">Cryptographic primitive</a></li>

<li><a href="Cryptanalysis" title="Cryptanalysis">Cryptanalysis</a></li>

<li><a href="Cryptocurrency" title="Cryptocurrency">Cryptocurrency</a></li>

<li><a href="Cryptosystem" title="Cryptosystem">Cryptosystem</a></li>

<li><a href="Cryptographic_nonce" title="Cryptographic nonce">Cryptographic nonce</a></li>

<li><a href="Cryptovirology" title="Cryptovirology">Cryptovirology</a></li>

<li><a href="Hash_function" title="Hash function">Hash function</a>

<ul><li><a href="Cryptographic_hash_function" title="Cryptographic hash function">Cryptographic hash function</a></li>

<li><a href="Key_derivation_function" title="Key derivation function">Key derivation function</a></li>

<li><a href="Secure_Hash_Algorithms" title="Secure Hash Algorithms">Secure Hash Algorithms</a></li></ul></li>

<li><a href="Digital_signature" title="Digital signature">Digital signature</a></li>

<li><a href="Kleptography" title="Kleptography">Kleptography</a></li>

<li><a href="Key_exchange" title="Key exchange">Key exchange</a></li>

<li><a href="Key_generator" title="Key generator">Key generator</a></li>

<li><a href="Key_schedule" title="Key schedule">Key schedule</a></li>

<li><a href="Key_stretching" title="Key stretching">Key stretching</a></li>

<li><a href="Keygen" title="Keygen">Keygen</a></li>

<li>Machines</li>

<li><a href="Cryptojacking_malware" class="mw-redirect" title="Cryptojacking malware">Cryptojacking malware</a></li>

<li><a href="Ransomware" title="Ransomware">Ransomware</a></li>

<li><a href="Random_number_generation" title="Random number generation">Random number generation</a>

<ul><li><a href="Cryptographically_secure_pseudorandom_number_generator" title="Cryptographically secure pseudorandom number generator">Cryptographically secure pseudorandom number generator</a> (CSPRNG)</li></ul></li>

<li><a href="Pseudorandom_noise" title="Pseudorandom noise">Pseudorandom noise</a> (PRN)</li>

<li><a href="Secure_channel" title="Secure channel">Secure channel</a></li>

<li><a href="Insecure_channel" class="mw-redirect" title="Insecure channel">Insecure channel</a></li>

<li><a href="Subliminal_channel" title="Subliminal channel">Subliminal channel</a></li>

<li><a href="Encryption" title="Encryption">Encryption</a></li>

<li><a href="Decryption" class="mw-redirect" title="Decryption">Decryption</a></li>

<li><a href="End-to-end_encryption" title="End-to-end encryption">End-to-end encryption</a></li>

<li><a href="Harvest_now%2C_decrypt_later" title="Harvest now, decrypt later">Harvest now, decrypt later</a></li>

<li><a href="Information-theoretic_security" title="Information-theoretic security">Information-theoretic security</a></li>

<li><a href="Plaintext" title="Plaintext">Plaintext</a></li>

<li><a href="Codetext" class="mw-redirect" title="Codetext">Codetext</a></li>

<li><a href="Ciphertext" title="Ciphertext">Ciphertext</a></li>

<li><a href="Shared_secret" title="Shared secret">Shared secret</a></li>

<li><a href="Trapdoor_function" title="Trapdoor function">Trapdoor function</a></li>

<li><a href="Trusted_timestamping" title="Trusted timestamping">Trusted timestamping</a></li>

<li><a href="Key-based_routing" title="Key-based routing">Key-based routing</a></li>

<li><a href="Onion_routing" title="Onion routing">Onion routing</a></li>

<li><a href="Garlic_routing" title="Garlic routing">Garlic routing</a></li>

<li><a href="Kademlia" title="Kademlia">Kademlia</a></li>

<li><a href="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="Cryptographic_hash_function" title="Cryptographic hash function">Cryptographic hash function</a></li>

<li><a href="Block_cipher" title="Block cipher">Block cipher</a></li>

<li><a href="Stream_cipher" title="Stream cipher">Stream cipher</a></li>

<li><a href="Symmetric-key_algorithm" title="Symmetric-key algorithm">Symmetric-key algorithm</a></li>

<li><a href="Authenticated_encryption" title="Authenticated encryption">Authenticated encryption</a></li>

<li><a href="Public-key_cryptography" title="Public-key cryptography">Public-key cryptography</a></li>

<li><a href="Quantum_key_distribution" title="Quantum key distribution">Quantum key distribution</a></li>

<li><a href="Quantum_cryptography" title="Quantum cryptography">Quantum cryptography</a></li>

<li><a href="Post-quantum_cryptography" title="Post-quantum cryptography">Post-quantum cryptography</a></li>

<li><a href="Message_authentication_code" title="Message authentication code">Message authentication code</a></li>

<li><a href="Cryptographically_secure_pseudorandom_number_generator" title="Cryptographically secure pseudorandom number generator">Random numbers</a></li>

<li><a href="Steganography" title="Steganography">Steganography</a></li></ul>

</div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div>

<ul><li><span class="noviewer" typeof="mw:File"><span title="Category"></span></span> Category</li></ul>

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