Contract Signatures in E-Commerce Applications

In this paper, we propose a notion of contract signatures used in e-commerce applications. This scheme adopts digital multi-signature scheme in public-key cryptography to facilitate fair signature exchange over network. Security proof under the random oracle model of this modified signature scheme is include. This proposed solution allows two parties to produce and exchange two ambiguous signatures which are fully ambiguous for any third party (i.e. 1 out ambiguity). The combination of these two ambiguous signatures forms the contract signature. There is no “keystone” (i.e. a secret key used in the concurrent signature) of the signature. In case anyone releases the contract signature to a verifier, both signers bind to the contract signature.