Secure E-cheques for Joint Accounts with Collective Signing Using Forward-Secure Multi-signature Scheme

With the modern world going on-line for all businesses, we need to transact with various business organizations all over the world using different modes of payment obtained through various Financial Institutions. We propose a scheme for Joint Account Holders with collective signing agreement to issue e-cheques. Our scheme is based on multi-signatures. When an e-cheque belonging to a Joint Account is submitted by a bank for clearance, the bank clearing the e-cheque can verify that it is signed by all the Joint Account Holders using a single verification equation. Also, the bank can maintain just a single public key for one Joint Account though multiple signers are involved. We have augmented the multi-signature scheme to provide forward security. This guarantees the security of cheques signed in the past even if the signer's secret key is exposed today.