A method for conveying a one-time password using blockchain includes: receiving proposed transaction data from a merchant system including payment credentials, receiving account details, and a transaction amount; identifying user account data associated with the payment credentials including an account identifier; identifying a one-time password; transmitting the one-time password and account identifier to a third party system; receiving a data identification value from an external computing device; identifying a blockchain data value included in a blockchain including a password value based on the received data identification value; validating, the identified one-time password based on the password value; and initiating payment of the transaction amount from a first transaction account associated with the payment credentials to a second transaction account associated with the receiving account details upon validation of the identified one-time password.