As defined by , an unknown key-share (UKS) attack on an authenticated

key agreement In cryptography, a key-agreement protocol is a protocol whereby two or more parties can agree on a key in such a way that both influence the outcome. If properly done, this precludes undesired third parties from forcing a key choice on the agreeing ...

(AK) or authenticated key agreement with key confirmation (AKC)

protocol Protocol may refer to: Sociology and politics * Protocol (politics), a formal agreement between nation states * Protocol (diplomacy), the etiquette of diplomacy and affairs of state * Etiquette, a code of personal behavior Science and technolog ...

is an attack whereby an entity

A

ends up believing she shares a key with

B

, and although this is in fact the case,

B

mistakenly believes the key is instead shared with an entity

E \neq A

. In other words, in a UKS, an opponent, say Eve, coerces honest parties Alice and Bob into establishing a

secret key A key in cryptography is a piece of information, usually a string of numbers or letters that are stored in a file, which, when processed through a cryptographic algorithm, can encode or decode cryptographic data. Based on the used method, the key ...

where at least one of Alice and Bob does not know that the secret key is shared with the other. For example, Eve may coerce Bob into believing he shares the key with Eve, while he actually shares the key with Alice. The “key share” with Alice is thus unknown to Bob.

References

*{{ Citation , last1 = Blake-Wilson , first1 = S. , last2 = Menezes , first2 = A. , contribution = Unknown Key-Share Attacks on the Station-to-Station (STS) Protocol , url = sa://cacr.uwaterloo.ca/techreports/1998/corr98-42.pdf , title = Public Key Cryptography , series = Lecture Notes in Computer Science , volume = 1560 , pages = 154–170 , year = 1999 , publisher = Springer Cryptography