- Key authentication
Key authentication is a problem that arises when using
public key cryptography. It is the process of assuring that the public key of "person A" held by "person B" does in fact belong to "person A".
symmetric keycryptography, this problem wasn't an issue as it was implicitly assumed that some "secure" method of key distribution guaranteed key authenticity. Of course, this merely moved the issue back a level, to that of security of key distribution. Crypto systems using asymmetric keyalgorithms do not evade a related problem. That a public key can be known by all without compromising the security of an encryption algorithm (for some such algorithms, though not for all) is certainly useful, but does not prevent some kinds of attacks. For example, a spoofing attack in which public key "A" is claimed publicly to be that of user Alice but is in fact, a private key belonging attacker Mallory is easily possible. No public key is inherently bound to any particular user, and any user relying on a defective binding (including Alice herself when she sends herself protected messages) will have trouble.
The simplest solution for this problem is for the two users concerned to meet face-to-face and exchange keys, However, for systems in which there are a large number of users or in which the users do not personally know each other (eg, Internet shopping) this is not practicable.
The most common solution to this problem is the use of key certificates and certificate authorities for them in a
public key infrastructuresystem, The certificate authorityacts as a 'trusted third party' for the communicating users and, using cryptographic binding methods (eg, digital signatures) represents to both parties involved that the public keys each holds which allegedly belong to the other, actually do so. A digital notary service, if you will. Such CAs can be private organizations providing such assurances, or government agencies, or some combination of the two. However, in a significant sense, this merely moves the key authentication problem back one level for any CA may make a good faith certification of some key but, through error or malice, be mistaken. Any reliance on a defective key certificate 'authenticating' a public key will cause problems. As a result, many people find all PKI designs unacceptably insecure.
Accordingly, key authentication methods are being actively researched.
Wikimedia Foundation. 2010.
Look at other dictionaries:
Key (cryptography) — In cryptography, a key is a piece of information (a parameter) that determines the functional output of a cryptographic algorithm or cipher. Without a key, the algorithm would produce no useful result. In encryption, a key specifies the… … Wikipedia
Authentication — (from Greek αυθεντικός; real or genuine, from authentes; author) is the act of establishing or confirming something (or someone) as authentic , that is, that claims made by or about the thing are true. This might involve confirming the identity… … Wikipedia
Key exchange — is any method in cryptography by which cryptographic keys are exchanged between users, allowing use of a cryptographic algorithm. If Alice and Bob wish to exchange encrypted messages, each must be equipped to decrypt received messages and to… … Wikipedia
Authentication server — Authentication servers are servers that provide authentication services to users or other systems. Users and other servers authenticate to such a server, and receive cryptographic tickets. These tickets are then exchanged with one another to… … Wikipedia
Key Wrap — constructions are a class of symmetric encryption algorithms designed to encapsulate (encrypt) cryptographic key material. The Key Wrap algorithms are intended for applications such as (a) protecting keys while in untrusted storage, or (b)… … Wikipedia
Authentication Header — IPsec im TCP/IP‑Protokollstapel: Anwendung HTTP IMAP SMTP DNS … Transport TCP UDP … Deutsch Wikipedia
Key-agreement protocol — 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… … Wikipedia
Key selection vector — The Key Selection Vector means the numerical associated with a Device Key Set and distributed by Licensor or its designee to Adopters and used to support authentication of Licensed Products and Revocation. It is considered a confidential set of… … Wikipedia
Authentication key identifier — An ISO term. ISO Message Authentication term. ISO Key Management term. The identification of the cryptographic key to be used for authentication. ISO Key Management term. The key identifier of a key to be used in the authentication of a… … International financial encyclopaedia
Authentication key — An ISO term. A cryptographic key used for authentication. When this key and the elements to be authenticated (authentication elements) are applied to the authentication algorithm, the result will be the message authentication code (MAC) or the… … International financial encyclopaedia