A system, method, and computer-readable medium for improving the security of an e-commerce system using Simple Mail Transfer Protocol (SMTP). The security of the e-commerce system is improved by receiving a transaction request via a response email that contains a token. This token is decoded to uncover the user's email address. The system then undertakes a verification using Sender Policy Framework (SPF) or DomainKeys Identified Mail (DKIM) to decide whether to accept or reject. Following this, a confirmation email, which includes a clickable link, is sent to the user's email address derived from the token. The transaction is processed once the user clicks on the link in the confirmation email, completing the security enhancement process.