Divisible On-Line/Off-Line Signatures

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 int...

• Type: Conference
• Year: 2009
• Where: CTRSA
• Authors: Chong-zhi Gao, Baodian Wei, Dongqing Xie, Chunming Tang
• Keywords: Cryptology, CTRSA 2009, Off-line, Off-line Phase, Off-line Signature Tokens