Divisible On-line/Off-line Signatures

Chong-zhi Gao; Baodian Wei; Dongqing Xie; Chunming Tang

Paper 2008/447

Divisible On-line/Off-line Signatures

Chong-zhi Gao, Baodian Wei, Dongqing Xie, and Chunming Tang

Abstract

On-line/Off-line signatures are used in a particular scenario where the signer must respond quickly once the message to be signed is presented. The idea is to split the signing procedure into two phases: the off-line and on-line phases. The signer can do some pre-computations in off-line phase before he sees the message to be signed. In most of these schemes, when signing a message $m$, a partial signature of $m$ is computed in the off-line phase. We call this part of signature the off-line signature token of message $m$. In some special applications, the off-line signature tokens might be exposed in the off-line phase. For example, some signers might want to transmit off-line signature tokens in the off-line phase in order to save the on-line transmission bandwidth. Another example is in the case of on-line/off-line threshold signature schemes, where off-line signature tokens are unavoidably exposed to all the players in the off-line phase. This paper discusses this exposure problem and introduces a new notion: divisible on-line/off-line signatures, in which exposure of off-line signature tokens in off-line phase is allowed. An efficient construction of this type of signatures is also proposed. Furthermore, we show an important application of divisible on-line/off-line signatures in the area of on-line/off-line threshold signatures.

Note: A small revision in the statement of Theorem 1.

Metadata

Available format(s): PDF PS
Publication info: Published elsewhere. An extended abstract of this paper appears in CT-RSA 2009, LNCS 5473, Springer-Verlag, 2009.
Keywords: Signature Schemes Divisible On-line Off-line Signatures On-line Off-line Threshold Signatures.
Contact author(s): czgao @ gzhu edu cn
History: 2009-04-20: last of 3 revisions; 2008-10-27: received; See all versions
Short URL: https://ia.cr/2008/447
License: CC BY

BibTeX

@misc{cryptoeprint:2008/447,
      author = {Chong-zhi Gao and Baodian Wei and Dongqing Xie and Chunming Tang},
      title = {Divisible On-line/Off-line Signatures},
      howpublished = {Cryptology {ePrint} Archive, Paper 2008/447},
      year = {2008},
      url = {https://eprint.iacr.org/2008/447}
}