Fuzzy identity-based encryption. (English) Zbl 1137.94355

Sahai, Amit; Waters, Brent

Cramer, Ronald (ed.), Advances in cryptology – EUROCRYPT 2005. 24th annual international conference on the theory and applications of cryptographic techniques, Aarhus, Denmark, May 22–26, 2005. Proceedings. Berlin: Springer (ISBN 3-540-25910-4/pbk). Lecture Notes in Computer Science 3494, 457-473 (2005).

Summary: We introduce a new type of Identity-Based Encryption (IBE) scheme that we call Fuzzy Identity-Based Encryption. In Fuzzy IBE we view an identity as set of descriptive attributes. A Fuzzy IBE scheme allows for a private key for an identity, \(\omega \), to decrypt a ciphertext encrypted with an identity, \(\omega'\), if and only if the identities \(\omega \) and \(\omega'\) are close to each other as measured by the “set overlap” distance metric. A Fuzzy IBE scheme can be applied to enable encryption using biometric inputs as identities; the error-tolerance property of a Fuzzy IBE scheme is precisely what allows for the use of biometric identities, which inherently will have some noise each time they are sampled. Additionally, we show that Fuzzy-IBE can be used for a type of application that we term “attribute-based encryption”.
In this paper we present two constructions of Fuzzy IBE schemes. Our constructions can be viewed as an Identity-Based Encryption of a message under several attributes that compose a (fuzzy) identity. Our IBE schemes are both error-tolerant and secure against collusion attacks. Additionally, our basic construction does not use random oracles. We prove the security of our schemes under the Selective-ID security model.
For the entire collection see [Zbl 1107.94001].

MSC:

94A60

Cryptography