Message authentication

<h2 id="description">Description</h2>
Message authentication or data origin authentication is an <a href="/facts/Information_security/horlrCln">information security</a> property that indicates that a message has not been modified while in transit (<a href="/facts/Data_integrity/g3XGbKIH">data integrity</a>) and that the receiving party can verify the source of the message.<a class="footnote-ref" id="fnref:2" href="#fn:2">2</a> Message <a href="/facts/Authentication/64y4S69b">authentication</a> does not necessarily include the property of <a href="/facts/Non-repudiation/uNAP1YIf">non-repudiation</a>.<a class="footnote-ref" id="fnref:3" href="#fn:3">3</a><a class="footnote-ref" id="fnref:4" href="#fn:4">4</a>

<h2 id="techniques">Techniques</h2>
Message authentication is typically achieved by using <a href="/facts/Message_authentication_code/mXxCP5Yl">message authentication codes</a> (MACs), <a href="/facts/Authenticated_encryption/u3229wI2">authenticated encryption</a> (AE), or <a href="/facts/Digital_signature/tY7e2pnW">digital signatures</a>.<a class="footnote-ref" id="fnref:5" href="#fn:5">5</a> The message authentication code, also known as digital authenticator, is used as an integrity check based on a secret key shared by two parties to authenticate information transmitted between them.<a class="footnote-ref" id="fnref:6" href="#fn:6">6</a> It is based on using a <a href="/facts/Cryptographic_hash_function/cuxkgbST">cryptographic hash</a> or <a href="/facts/Symmetric-key_algorithm/5zfe0b76">symmetric encryption algorithm</a>.<a class="footnote-ref" id="fnref:7" href="#fn:7">7</a> The authentication key is only shared by exactly two parties (e.g. communicating devices), and the authentication will fail in the existence of a third party possessing the key since the <a href="/facts/Algorithm/fnl5NmRt">algorithm</a> will no longer be able to detect <a href="/facts/Forgery/I9De2P20">forgeries</a> (i.e. to be able to validate the unique source of the message).<a class="footnote-ref" id="fnref:8" href="#fn:8">8</a> In addition, the key must also be randomly generated to avoid its recovery through brute-force searches and related-key attacks designed to identify it from the messages transiting the medium.<a class="footnote-ref" id="fnref:9" href="#fn:9">9</a>
Some cryptographers distinguish between "message authentication without secrecy" systems – which allow the intended receiver to verify the source of the message, but they don't bother hiding the plaintext contents of the message – from <a href="/facts/Authenticated_encryption/u3229wI2">authenticated encryption</a> systems.<a class="footnote-ref" id="fnref:10" href="#fn:10">10</a> Some cryptographers have researched <a href="/facts/Subliminal_channel/sPGzdU8U">subliminal channel</a> systems that send messages that appear to use a "message authentication without secrecy" system, but in fact also transmit a secret message.

<h2 id="related-concepts">Related concepts</h2>
Data origin authentication and non-repudiation have been also studied in the framework of quantum cryptography.<a class="footnote-ref" id="fnref:11" href="#fn:11">11</a><a class="footnote-ref" id="fnref:12" href="#fn:12">12</a>

<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Data_integrity/g3XGbKIH">Data integrity</a></li>
<li><a href="/facts/Authentication/64y4S69b">Authentication</a></li>
<li><a href="/facts/Deniable_authentication/QtNjCJ4V">Deniable authentication</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1">Mihir Bellare. "Chapter 7: Message Authentication" (PDF). CSE 207: Modern Cryptography. Lecture notes for cryptography course. Archived from the original (PDF) on 2018-10-09. Retrieved 2015-05-11. <a href="/wiki/Mihir_Bellare" target="_blank">/wiki/Mihir_Bellare</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></li>
<li id="fn:2">Mihir Bellare. "Chapter 7: Message Authentication" (PDF). CSE 207: Modern Cryptography. Lecture notes for cryptography course. Archived from the original (PDF) on 2018-10-09. Retrieved 2015-05-11. <a href="/wiki/Mihir_Bellare" target="_blank">/wiki/Mihir_Bellare</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">Alfred J. Menezes; Paul C. van Oorschot; Scott A. Vanstone. "Chapter 9 - Hash Functions and Data Integrity" (PDF). Handbook of Applied Cryptography. p. 361. Archived from the original on 2021-02-03. Retrieved 2015-05-11. <a href="/wiki/Alfred_J._Menezes" target="_blank">/wiki/Alfred_J._Menezes</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">"Data Origin Authentication". Web Service Security. Microsoft Developer Network. 14 July 2010. Archived from the original on 19 May 2017. Retrieved 11 May 2015. <a href="https://msdn.microsoft.com/en-us/library/ff648434.aspx" target="_blank">https://msdn.microsoft.com/en-us/library/ff648434.aspx</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">Alfred J. Menezes; Paul C. van Oorschot; Scott A. Vanstone. "Chapter 9 - Hash Functions and Data Integrity" (PDF). Handbook of Applied Cryptography. p. 361. Archived from the original on 2021-02-03. Retrieved 2015-05-11. <a href="/wiki/Alfred_J._Menezes" target="_blank">/wiki/Alfred_J._Menezes</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">Patel, Dhiren (2008). Information Security: Theory and Practice. New Delhi: Prentice Hall India Private Lt. p. 124. ISBN 978-81-203-3351-2. <a href="978-81-203-3351-2" target="_blank">978-81-203-3351-2</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
<li id="fn:7">Jacobs, Stuart (2011). Engineering Information Security: The Application of Systems Engineering Concepts to Achieve Information Assurance. Hoboken, NJ: John Wiley & sons. p. 108. ISBN 978-0-470-56512-4. <a href="978-0-470-56512-4" target="_blank">978-0-470-56512-4</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></li>
<li id="fn:8">Walker, Jesse (2013). "Chapter 13 – Internet Security". In Vacca, John R. (ed.). Computer and Information Security Handbook (3rd ed.). Morgan Kaufmann Publishers. pp. 256–257. doi:10.1016/B978-0-12-803843-7.00013-2. ISBN 978-0-12-803843-7. <a href="978-0-12-803843-7" target="_blank">978-0-12-803843-7</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></li>
<li id="fn:9">Walker, Jesse (2013). "Chapter 13 – Internet Security". In Vacca, John R. (ed.). Computer and Information Security Handbook (3rd ed.). Morgan Kaufmann Publishers. pp. 256–257. doi:10.1016/B978-0-12-803843-7.00013-2. ISBN 978-0-12-803843-7. <a href="978-0-12-803843-7" target="_blank">978-0-12-803843-7</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></li>
<li id="fn:10">Longo, G.; Marchi, M.; Sgarro, A. (4 May 2014). Geometries, Codes and Cryptography. Springer. p. 188. ISBN 978-3-7091-2838-1. Archived from the original on 9 January 2024. Retrieved 8 July 2015. <a href="978-3-7091-2838-1" target="_blank">978-3-7091-2838-1</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></li>
<li id="fn:11">Pirandola, S.; Andersen, U. L.; Banchi, L.; Berta, M.; Bunandar, D.; Colbeck, R.; Englund, D.; Gehring, T.; Lupo, C.; Ottaviani, C.; Pereira, J. (2020). "Advances in Quantum Cryptography". Advances in Optics and Photonics. 12 (4): 1012–1236. arXiv:1906.01645. Bibcode:2020AdOP...12.1012P. doi:10.1364/AOP.361502. S2CID 174799187. <a href="/wiki/ArXiv_(identifier)" target="_blank">/wiki/ArXiv_(identifier)</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></li>
<li id="fn:12">Nikolopoulos, Georgios M.; Fischlin, Marc (2020). "Information-Theoretically Secure Data Origin Authentication with Quantum and Classical Resources". Cryptography. 4 (4): 31. arXiv:2011.06849. doi:10.3390/cryptography4040031. S2CID 226956062. <a href="https://doi.org/10.3390%2Fcryptography4040031" target="_blank">https://doi.org/10.3390%2Fcryptography4040031</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></li>
</ol>

Message authentication open-in-new

Message authentication