Secure e-Cheque Clearance between Financial Institutions

There are many situations where there is lack of trust between transacting financial institutions (FIs include banks). In such situations confidential or financial information cannot be revealed. For such an untrusted environment a zero knowledge protocol is devised to perform secure inter FI e-cheque clearance operations. Also, there is no trusted centralised authority controlling the operations. The e-cheque system is designed with message integrity, authentication and non-repudiation features, strong enough to prevent fraud against the FIs and their customers. To verify digital signatures one needs to have the public key of the signer. However FI´s cannot store public keys of all possible payer´s of e-cheques and their corresponding servicing FIs. Therefore a method is formulated in which one can verify that two signatures received from a signer indeed belong to the same signer without the help of public key of the signer.