{{Short description|System to verify the source and or authenticity of a message}}{{Lead too short|date=June 2024|reason=it misses a summary of the content of each section}}
In [[information security]], '''message authentication''' or '''data origin authentication''' is a property that a message has not been modified while in transit ([[data integrity]]) and that the receiving party can verify the source of the message.<ref name="cse207">{{cite book |author=[[Mihir Bellare]] |title=CSE 207: Modern Cryptography |work= |at=Lecture notes for cryptography course |chapter=Chapter 7: Message Authentication |chapter-url=https://cseweb.ucsd.edu/~mihir/cse207/w-mac.pdf |access-date=2015-05-11 |archive-date=2018-10-09 |archive-url=https://web.archive.org/web/20181009122804/http://cseweb.ucsd.edu/~mihir/cse207/w-mac.pdf |url-status=dead }}</ref>
== Description == Message authentication or data origin authentication is an [[information security]] property that indicates that a message has not been modified while in transit ([[data integrity]]) and that the receiving party can verify the source of the message.<ref name="cse207" /> Message [[authentication]] does not necessarily include the property of [[non-repudiation]].<ref name="hac">{{Cite book |title=Handbook of Applied Cryptography |author=[[Alfred J. Menezes]] |author2=[[Paul C. van Oorschot]] |author3=[[Scott A. Vanstone]] |chapter=Chapter 9 - Hash Functions and Data Integrity |page=361 |url=https://cacr.uwaterloo.ca/hac/ |chapter-url=https://cacr.uwaterloo.ca/hac/about/chap9.pdf |access-date=2015-05-11 |archive-date=2021-02-03 |archive-url=https://web.archive.org/web/20210203194011/https://cacr.uwaterloo.ca/hac/ |url-status=live }}</ref><ref name="msdn">{{Cite book |title=Web Service Security |chapter=Data Origin Authentication |date=14 July 2010 |publisher=[[Microsoft Developer Network]] |chapter-url=https://msdn.microsoft.com/en-us/library/ff648434.aspx |access-date=11 May 2015 |archive-date=19 May 2017 |archive-url=https://web.archive.org/web/20170519201452/https://msdn.microsoft.com/en-us/library/ff648434.aspx |url-status=live }}</ref>
== Techniques == Message authentication is typically achieved by using [[message authentication code]]s (MACs), [[authenticated encryption]] (AE), or [[digital signature]]s.<ref name=hac /> 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.<ref>{{Cite book|title=Information Security: Theory and Practice|last=Patel|first=Dhiren|publisher=Prentice Hall India Private Lt.|year=2008|isbn=978-81-203-3351-2|location=New Delhi|page=124}}</ref> It is based on using a [[cryptographic hash function|cryptographic hash]] or [[symmetric-key algorithm|symmetric encryption algorithm]].<ref>{{Cite book|title=Engineering Information Security: The Application of Systems Engineering Concepts to Achieve Information Assurance|last=Jacobs|first=Stuart|publisher=John Wiley & sons|year=2011|isbn=978-0-470-56512-4|location=Hoboken, NJ|page=108}}</ref> 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 [[algorithm]] will no longer be able to detect [[Forgery|forgeries]] (i.e. to be able to validate the unique source of the message).<ref name="Vacca">{{cite book |chapter=Chapter 13 – Internet Security |first=Jesse |last=Walker |title=Computer and Information Security Handbook |editor-last=Vacca |editor-first=John R. |publisher=Morgan Kaufmann Publishers |edition=3rd |year=2013 |isbn=978-0-12-803843-7 |pages=256–257 |doi=10.1016/B978-0-12-803843-7.00013-2}}</ref> 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.<ref name="Vacca" />
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 [[authenticated encryption]] systems.<ref>{{cite book |first1=G. |last1=Longo |first2=M. |last2=Marchi |first3=A. |last3=Sgarro |url=https://books.google.com/books?id=WvYrBAAAQBAJ |title=Geometries, Codes and Cryptography |date=4 May 2014 |page=188 |publisher=Springer |isbn=978-3-7091-2838-1 |access-date=8 July 2015 |archive-date=9 January 2024 |archive-url=https://web.archive.org/web/20240109202625/https://books.google.com/books?id=WvYrBAAAQBAJ |url-status=live }}</ref> Some cryptographers have researched [[subliminal channel]] systems that send messages that appear to use a "message authentication without secrecy" system, but in fact also transmit a secret message.
== Related concepts == Data origin authentication and non-repudiation have been also studied in the framework of quantum cryptography.<ref>{{cite journal|last1=Pirandola|first1=S.|last2=Andersen|first2=U. L.|last3=Banchi|first3=L.|last4=Berta|first4=M.|last5=Bunandar|first5=D.|last6=Colbeck|first6=R.|last7=Englund|first7=D.|last8=Gehring|first8=T.|last9=Lupo|first9=C.|last10=Ottaviani|first10=C.|last11=Pereira|first11=J.|title=Advances in Quantum Cryptography|journal=Advances in Optics and Photonics|year=2020|volume=12|issue=4|pages=1012–1236|doi=10.1364/AOP.361502|arxiv=1906.01645|bibcode=2020AdOP...12.1012P|s2cid=174799187}}</ref><ref>{{Cite journal|last1=Nikolopoulos|first1=Georgios M.|last2=Fischlin|first2=Marc|date=2020|title=Information-Theoretically Secure Data Origin Authentication with Quantum and Classical Resources|journal=Cryptography|language=en|volume=4|issue=4|page=31|doi=10.3390/cryptography4040031|arxiv=2011.06849|s2cid=226956062|doi-access=free}}</ref>
== See also == * [[Data integrity]] * [[Authentication]] * [[Deniable authentication]]
== References == {{Reflist}}
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