[SW05] Fuzzy Identity-Based Encryption

Authors: Amit Sahai, Brent Waters | Venue: Eurocrypt 2005 | Source

Abstract

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, ${\omega }^{\prime }$, if and only if the identities $\omega$ and ${\omega }^{\prime }$ 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 to build a new type of Attribute-Based Encryption scheme. We construct two Fuzzy IBE schemes and prove their security under the Selective-ID security model.