关键词: PKI, 密钥保护, 数字签名, 多方计算, 门限密码

Abstract: tA basic principle of modern cryptography is that “all secrets are in the secret key”. The cryptographic algorithm is publicly available, but the key must be kept confidential absolutely, to ensure the security of the cryptography and the information system. In this paper, through a review of the history about the digital signature key protection mechanism, we analyze the security features of these mechanisms, introduce the cloud collaborative key protection mechanism which emerge in recent years, and the research progress and the industrial practices about this mechanism, and also analyze the technical features, security, use scenarios and future trends of it，analyze the value of the cloud collaborative key protection mechanism and the influence to cryptographyic industry.

Key words: PKI, key protection, digital signature, multiparty calculation, threshold cryptography