International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: ID-based Cryptography from Composite Degree Residuosity

Man Ho Au
Victor K. Wei
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Abstract: We present identity-based identification (resp. encryption, signature, blind signature,ring signature) from composite degree residuosity (CDR). Constructions of identifications and signatures motivated by several existing CDR-based bandwidth-efficient encryption schemes are presented. Their securities are proven equivalent to famous hard problems, in the random oracle model. Motivated by Cocks,we construct an identity-based encryption from CDR. Its security is proven equivalent to a new problem, the JSR (Jacobi Symbol of Roots of two quadratic polynomials) Problem. We prove JSR is at least as hard as QRP (Quadratic Residuosity Problem). Furthermore, we present the first two-way equivalence reduction of the security of Cocks' IBE, to the JSR Problem.
  title={ID-based Cryptography from Composite Degree Residuosity},
  booktitle={IACR Eprint archive},
  keywords={ID-based Cryptography},
  note={ 12611 received 12 Jul 2004, last revised 12 Jul 2004},
  author={Man Ho Au and Victor K. Wei},