Based on the RSA problem, Zhou et al.’s proposed a proxy-protected proxy signature scheme. They claimed that their scheme were secure and efficient. However, this paper shows that their proposed proxy-protected proxy signature scheme is insecure against the replaced warrant attack: the original signer can remove the old warrant from a valid proxy signature and then construct a new warrant, and ...

In current proxy signature schemes, an original signer delegates her signing capability to a proxy signer, and then the proxy signer can sign messages on behalf of the original signer. Although these schemes have succeeded in proxy delegations, they share a common problem. That is, a verifier cannot ascertain that a proxy signature was signed by the proxy signer during the valid delegation peri...

Proxy ‘Actualism’ Karen Bennett Forthcoming in Philosophical Studies

Proxy signatures are very useful tools when one needs to delegate his/her signing capability to other party. After Mambo et al.’s first scheme was announced, many proxy signature schemes and various types of proxy signature schemes have been proposed. Due to the various applications of the bilinear pairings in cryptography, there are many IDbased signature schemes have been proposed. In this pa...

In 1998, Blaze, Bleumer, and Strauss proposed a kind of cryptographic primitive called proxy re-encryption[3]. In proxy re-encryption, a proxy can transform a ciphertext computed under Alice’s public key into one that can be opened under Bob’s decryption key. In 2007, Matsuo proposed the concept of four types of proxy re-encryption schemes: CBE(Certificate Based Public Key Encryption) to IBE(Id...

Proxy signature is a useful cryptographic primitive that allows signing right delegation. In a proxy signature scheme, an original signer can delegate his/her signing right to a proxy signer (or a group of proxy signers) who can then sign documents on behalf of the original signer. In this paper, we investigate the problem of proxy signature with revocation. The revocation of delegated signing ...