A secure protocol for transactions, such as electronic commerce transactions, is described that provides improved security through exploiting an independent (where this independence is logical and/or physical) communication path (e.g., between a customer and a back-end financial institution), ensuring that key financial information remains within the back-end financial institutions themselves. Hence, this protocol directly reduces cyber-crime risks through improvements to transaction security. In addition, various implementations of the secure protocol provide non-repudiation for one or more of the entities involved in the transaction.