中文摘要：

文章首先提出一个代理解签密方案，此方案中原始的解签密者把消息划分为不同主题．并把解签密的权力按照主题分别授权给不同的代理解签密者。代理解签密者能直接解密其授权主题下的签密密文。此外，基于公告牌提出一个变体代理解签密方案，此方案中原始解签密者可以通过公告牌随时终止任意代理解签密者的授权。

英文摘要：

This paper presents a signcryption scheme with proxy unsigncryption （SSPU）, in which the original unsignerypter divides messages into various subjects and delegates his unsigncryption powers under different subjects to different proxies. The authorized proxies can directly unsigncrypt ciphertexts under their delegated subjects for the original signcrypter. Moreover, a variant scheme with bulletin board is proposed, in which the original unsigncrypter can temporarily abort the proxies＇ authorization even if the delegation is still during the valid period. So it is very practical when there are corrupted proxies.