一种可转换多方签名方案

可转换的鉴定加密方案允许签名人用他选择的消息生成一个有效的经鉴定的密文，而且只有指定的接受者能够恢复得到消息。接受者还可以转换经过鉴定的密文成普通的签名。以前提出的可转换鉴定方案只能允许一个签名者生成一个经鉴定密文，而这在多人环境下是不太合适的。本文详细阐述了多方签名方案的优点，提出的可转换多方签名鉴定方案有以下优点：生成的鉴别密文的大小独立于参与签名的总人数；除了指定的接受人外，其他人都不能获得签名的消息和检验相应的签名；签名是由一组签名人而非一个签名人协作生成的；接受者能转换经鉴定的密文为普通签名。

A Convertible Multi-signature Scheme

A convertible authenticated encryption scheme allows the signer to generate a valid authenticated ciphertext on his chosen message such that only the designated recipient can retrieve the message. Further, the recipient has the ability to convert the authenticated ciphertext into ordinary signature in case of a dispute or repudiation. The previous proposed schemes can only allow one signer to produce the authenticated ciphertext. It might be inadequate for multiparty environments. In this paper, we propose a convertible multi-authenticated encryption scheme which has the following advantages： The size of the generated authenticated ciphertext is independent of the number of total participating signers. Except for the designated recipient, no one can obtain the signed message and verify its corresponding signature. The signature is cooperatively produced by a group of signers instead of a single signer.In case of a later dispute on repudiation, the recipient has the ability to convert the authenticated ciphertext into an ordinary one.