International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Efficient and Universally Composable Committed Oblivious Transfer and Applications

Juan Garay
Philip MacKenzie
Ke Yang
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Abstract: Committed Oblivious Transfer (COT) is a useful cryptographic primitive that combines the functionalities of bit commitment and oblivious transfer. In this paper, we introduce an extended version of COT (ECOT) which additionally allows proofs of relations among committed bits, and we construct an efficient protocol that securely realizes an ECOT functionality in the universal-composability (UC) framework in the common reference string (CRS) model. Our construction is more efficient than previous (non-UC) constructions of COT, involving only a constant number of exponentiations and communication rounds. Using the ECOT functionality as a building block, we construct efficient UC protocols for general two-party and multi-party functionalities (in the CRS model), each gate requiring a constant number of ECOT's.
  title={Efficient and Universally Composable Committed Oblivious Transfer and Applications},
  booktitle={IACR Eprint archive},
  keywords={public-key cryptography / oblivious transfer, bit commitment, uni},
  note={An extended abstract of this paper appeared in the Proceedsing of the first Theory of Cryptography Conference, 2004. 12471 received 22 Feb 2004, last revised 23 Feb 2004},
  author={Juan Garay and Philip MacKenzie and Ke Yang},