New Signature Derivation using Existing Signatures

In banks, as part of normal procedure, receipts for deposits, statements of the bank account or credit card account are regularly issued to customers. This whole procedure is time consuming. Also, officials often find it difficult to sign for all the documents required by a customer though the related sub-processes are completed and corresponding documents are digitally signed. We consider the scenario of e-receipt generation during echeque processing, where the subprocess like e-cheque verification and receiving acknowledgement from cheque clearing bank are completed and digitally signed. But there is need for e-receipt to be generated by the bank for the customer. When the number of e-cheques increase, it is a burden for the bank to issue e-receipts. In this scenarios, we observe that, it would be interesting if customers themselves are capable of generating signed receipts based on the signatures available on already completed transactions. This calls for signature of a document to be derived from existing signatures of related documents. By this a customer can derive signatures on his own without the intervention of the bank which inturn reduces the work load on the bank. In all the signature derivations we make, we take care that a new signature derived is similar to the one that the signer would have generated if he had signed himself and also all signatures either existing or derived are verified using the same verification equation.