Cloud-based electronic payment processing

1. A method of cloud-based electronic payment processing, the method comprising:

a payment processing server generating an asymmetric cryptographic key pair, over one secure communications channel providing a mobile device with a credential comprising one cryptographic key of the cryptographic key pair, generating a unique single-use payment number, uniquely associating the cryptographic key pair and the single-use payment number with a financial account by saving another cryptographic key of the cryptographic key pair in a pending transaction database uniquely in association with the single-use payment number and the financial account;

the payment processing server encrypting the single-use payment number with the another cryptographic key;

the mobile device (i) receiving from a payment terminal a card number request requesting a card number from the mobile device, (ii) establishing with the payment processing server another secure communications channel distinct from the one secure communications channel, (iii) receiving the encrypted single-use payment number from the payment processing server over the another secure communications channel, (iv) generating a decrypted single-use payment number by decrypting the encrypted single-use payment number with the one cryptographic key, and (v) transmitting the decrypted single-use payment number to the payment terminal in response to the card number request;

the payment processing server receiving from the payment terminal a payment completion request requesting completion of a financial transaction, the payment completion request including the decrypted single-use payment number and a transaction amount;

the payment processing server identifying the financial account associated with the decrypted single-use payment number by querying the pending transaction database with the decrypted single-use payment number, and

the payment processing server initiating completion of the financial transaction by one of transferring funds from, and obtaining authorization for a charge to, the identified financial account in an amount equal to the transaction amount.

2. The method according to claim 1 , wherein the single-use payment number has a life-time period, and the effecting completion of the financial transaction comprises the payment processing server confirming non-expiry of the life time period and effecting the completion of the financial transaction after confirming the non-expiry of the life-time period.

3. The method according to claim 1 , wherein the effecting completion of the financial transaction comprises the payment processing server purging the asymmetric cryptographic key pair and the association from the pending transaction database after the identifying the financial account associated with the decrypted single-use payment number.

4. The method according to claim 1 , wherein the one cryptographic key comprises a public cryptographic key, and the another cryptographic key comprise a private cryptographic key.

5. A payment processing server comprising:

a computer processing system comprising a pending transaction database and configured to:

(i) generate an asymmetric cryptographic key pair, generate a unique single-use payment number, over one secure communications channel provide a mobile device with a credential comprising one cryptographic key of the cryptographic key pair, and uniquely associate the cryptographic key pair and the single-use payment number with a financial account by saving another cryptographic key of the cryptographic key pair in the pending transaction database uniquely in association with the single-use payment number and the financial account;

(ii) establish with the mobile device another secure communications channel distinct from the one secure communications channel, encrypt the unique single-use payment number with the another cryptographic key, and transmit the encrypted single-use payment number to the mobile device over the another secure communications channel, the computer processing system being configured to encrypt the single-use payment number by confirming that the encrypted single-use payment number does not identify the financial account;

(iii) receive from a payment terminal a payment completion request requesting completion of a financial transaction, the payment completion request including the unique single-use payment number and a transaction amount;

(iv) identify the financial account associated with the received unique single-use payment number by querying the pending transaction database with the received unique single-use payment number, and

(v) initiate completion of the financial transaction by one of transferring funds from, and obtaining authorization for a charge to, the identified financial account in an amount equal to the transaction amount.

6. The payment processing server according to claim 5 , wherein the single-use payment number has a life-time period, and the computer processing system is configured to confirm non-expiry of the life time period, and to effect the completion of the financial transaction after confirming the non-expiry of the life-time period.

7. The payment processing server according to claim 5 , wherein the computer processing system is configured to effect the completion of the financial transaction by purging the asymmetric cryptographic key pair and the association from the pending transaction database after the identifying the financial account associated with the decrypted single-use payment number.

8. The payment processing server according to claim 5 , wherein the one cryptographic key comprises a public cryptographic key, and the another cryptographic key comprise a private cryptographic key.

9. A non-transient computer-readable medium carrying computer processing instructions stored thereon which, when executed by a computer, cause the computer to perform a sequence comprising:

generating an asymmetric cryptographic key pair, over one secure communications channel providing a mobile device with a credential comprising one cryptographic key of the cryptographic key pair, generating a unique single-use payment number, and uniquely associating the cryptographic key pair and the single-use payment number with a financial account by saving another cryptographic key of the cryptographic key pair in a pending transaction database uniquely in association with the single-use payment number and the financial account, the cryptographic key pair and the single-use payment number each being uniquely associated with the financial account;

establishing with the mobile device another secure communications channel distinct from the one secure communications channel, encrypting the unique single-use payment number with the another cryptographic key, and transmitting the encrypted single-use payment number to the mobile device over the another secure communications channel, the encrypting the single-use payment number comprising confirming that the encrypted single-use payment number does not identify the financial account;

receiving from a payment terminal a payment completion request requesting completion of a financial transaction, the payment completion request including the unique single-use payment number and a transaction amount;

identifying the financial account associated with the received unique single-use payment number by querying the pending transaction database with the received unique single-use payment number, and

initiating completion of the financial transaction by one of transferring funds from, and obtaining authorization for a charge to, the identified financial account in an amount equal to the transaction amount.