Identity based partial aggregate signature scheme without pairing

An identity based signature allows users to sign their documents using their private keys and the signature can be verified by any one, using the identity of the signer and public parameters of the system. An aggregate signature scheme is a digital signature scheme which allows aggregation of different signatures by different users on different messages. The primary objective of aggregate signature scheme is to achieve both computational and communication efficiency. Here, we propose an identity based aggregate signature scheme, which uses a variation of light weight Schnorr type identity based signature scheme, where in the signers need not agree upon a common randomness and the aggregation is done without having any kind of interaction among the signers. The scheme is pairing free even for aggregate signature verification. The scheme is computationally efficient because it avoids costly bilinear pairing operation. It should be noted that our signature achieves only partial aggregation because the private key of each user is generated by a randomized extract algorithm and hence a random value is to be propagated with each single signature generated.