Paper 2007/133

New Communication-Efficient Oblivious Transfer Protocols Based on Pairings

Helger Lipmaa


We construct two simple families of two-message $(n,1)$-oblivious transfer protocols based on degree-$t$ homomorphic cryptosystems with the communication of respectively $1+\lceil n/t \rceil$ and $3+\lceil n/(t+1) \rceil$ ciphertexts. The construction of both families relies on efficient cryptocomputable conditional disclosure of secret protocols; the way this is done may be of independent interest. The currently most interesting case $t=2$ can be based on the Boneh-Goh-Nissim cryptosystem. As an important application, we show how to reduce the communication of virtually any existing oblivious transfer protocols by proposing a new related communication-efficient generic transformation from computationally-private information retrieval protocols to oblivious transfer protocols.

Note: Changes are only decorative compared to July 2007 version.

Available format(s)
Cryptographic protocols
Publication info
Published elsewhere. Accepted to ISC 2008
Conditional disclosure of secretshomomorphic encryptionoblivious transfer
Contact author(s)
h lipmaa @ cs ucl ac uk
2008-06-19: last of 3 revisions
2007-04-18: received
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Creative Commons Attribution


      author = {Helger Lipmaa},
      title = {New Communication-Efficient Oblivious Transfer Protocols Based on Pairings},
      howpublished = {Cryptology ePrint Archive, Paper 2007/133},
      year = {2007},
      note = {\url{}},
      url = {}
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