International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Fuzzy Identity Based Encryption

Amit Sahai
Brent Waters
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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, $\omega'$, 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.
  title={Fuzzy Identity Based Encryption},
  booktitle={IACR Eprint archive},
  keywords={public-key cryptography / identity based encryption},
  note={ 12845 received 29 Mar 2004, last revised 3 Mar 2005},
  author={Amit Sahai and Brent Waters},