Abstract: The proposed certificateless public key cryptosystem resolves key escrow problem in the?identity-based and certificate-
based public key cryptosystem. Combined with the advantage of certificateless  signature scheme, based on discrete logarithms problem and Lein Harn et al’s certificateless signature, a DL-based certificateless signature scheme with message recovery is proposed. The proposed scheme is secure against key escrow, and can reduce the computational cost, which improves its security and efficiency.

Key words: discrete logarithms, message recovery, ceritficateless public key, key escrow

摘要： 无证书密码公钥系统的提出，解决了基于身份和基于证书公钥密码系统中的密钥托管问题。结合无证书签名体制的这个优点，基于离散对数和Lein Harn等人的无证书数字签名方案，提出了一个离散对数上的信息可恢复的无证书签名方案。该方案能够抵制密钥托管问题，可以减少传输消息本身所需要的费用，同时能够满足Lein Harn等人无证书签名方案所满足的优点，其安全性和效率都得到了提高。

关键词: 离散对数, 信息恢复, 无证书公钥, 密钥托管