Cryptanalysis of an Identity Based Signcryption without Random Oracles
Signcryption is a cryptographic primitive that performs digital signature and public key encryption simultaneously, at lower computational costs and communication overhead than signing and encrypting separately. Recently, Yu et al. proposed an identity based signcryption scheme with a claimed proof of security. We show that their scheme is not secure even against a chosen-plaintext attack.
signcryption identity-based cryptography chosen plaintext attack