  Signcryption is a cryptographic primitive which performs encryption and
signature in a single logical step. In conventional signcryption only receiver
of the signcrypted text can verify the authenticity of the origin i.e.
signature of the sender on the message after decrypting the cipher text. In
public verifiable signcryption scheme anyone can verify the authenticity of the
origin who can access the signcrypted text i.e. signature of the sender on the
cipher text. Public verifiable signcryption scheme in which the receiver can
convince a third party, by providing additional information other than his
private key along with the signcryption is called third party verifiable
signcryption schemes. In this paper we proposed an efficient identity based
public verifiable signcryption scheme with third party verification and proved
its security in the random oracle model.

Cryptography and Security