可证明安全的单向可变门限代理重签名方案

Unidirectional Variable Threshold Proxy Re-signature Scheme with Provable Security

现有门限代理重签名方案的门限值基本是固定的,但实际应用中需要根据消息的重要程度灵活地变化门限值。为此,基于S_(uni)门限代理重签名方案,提出一种单向可变门限代理重签名方案。在每次进行重签名前,系统会动态设定门限值,每个代理将最初接收的部分子密钥进行重新计算,得到最新门限值下的重签名密钥及其对应的验证公钥,且系统只需提供受托者的公钥信息,避免了受托者承担安全风险。与现有单向可变重签名方案相比,该方案计算效率和安全性更高,签名长度更短。

In most existing threshold proxy re-signature schemes, threshold value is essentially immutable. However, depending on the significance of re-signature message, the value should be changed dynamically in many practical applications. Based on proxy re-signature scheme Suai this paper designs a new threshold proxy re-signature scheme which is unidirectional and variable. The system sets the new value of threshold before each re-signature, each agent re-calculates originally received sub-key partially, then each proxy can generate corresponding re-signature sub-key and verification key non-interactively. In order to protect the trustee security and avoid risk, system provides the public key when generating re-signature key. Compared with other unidirectional and variable re-signature schemes, this scheme can provide better efficiency in computation cost and signature length, and it has high security.