Abstract: Embodiments herein include a method implemented by a client device used by a consumer to securely conduct a financial transaction. The method includes generating a unique message digest by applying a cryptographic hash function to payment information uniquely associated with the consumer. The method also entails encrypting the unique message digest using a public key of a public-private key pair uniquely issued to the consumer, to obtain an encrypted digest. Finally, the method includes encrypting the encrypted digest and an index value using a symmetric key, to generate a card number to be sent to an authorization server for authorization of the financial transaction. This index value maps at the authorization server to the private key of the public-private key pair and to the payment information.