Systems and methods for cryptographic authentication of contactless cards

1. A contactless card authentication system, comprising:

a client device including a processor and a card reader; and

a client application comprising instructions for execution on the client device,

wherein the client application is in data communication with a contactless card and the card application is in data communication with an authentication server over a network, and

wherein the client application is configured to:

receive a transaction lockdown request;

send a request to the authentication server to permit a transaction approval within a time period;

receive the transaction approval via an authentication tap from the contactless card;

send the transaction approval to the authentication server; and

receive an allowance response from the authentication server, when the transaction approval is received by the authentication server within the time period, or

receive a disallowance response from the authentication server, when the transaction approval is received by the authentication server after the time period.

2. The contactless card authentication system of claim 1 , wherein the client application is further configured to:

receive a card-present type or a card-not-present type; and

send the card-present type or the card-not-present type to the authentication server.

3. The contactless card authentication system of claim 2 , wherein the card-not-present type is sent before the request to the server to permit the transaction approval.

4. The contactless card authentication system of claim 1 , wherein the client application is further configured to:

request transaction notifications from the authentication server;

receive a notification from the authentication server, the notification being one of the transaction notifications; and

display the notification.

5. The contactless card authentication system of claim 4 , wherein the request to the authentication server to begin to allow the transaction approval is sent after receiving the notification.

6. The contactless card authentication system of claim 5 , wherein the transaction approval via the authentication tap is requested upon displaying the notification.

7. The contactless card authentication system of claim 1 , wherein the client application is further configured to modify the time period.

8. A contactless card authentication method, comprising:

receiving, by a client application, a pre-approval option selection for a pre-approved transaction;

sending, by the client application, a request to an authentication server to permit a transaction pre-approval within a time period;

receiving, by the client application, a transaction notification from the authentication server;

matching, by the client application, the transaction notification to the pre-approved transaction;

requesting, by the client application, authentication in response to the transaction notification;

receiving, by the client application, a tap from a contactless card on a client device;

sending, by the client application, the transaction pre-approval to the authentication server;

receiving, by the client application, an allowance response from the authentication server when the transaction pre-approval is received by the authentication server within the time period, or a disallowance response from the authentication server when the transaction pre-approval is received by the authentication server after the time period; and

receiving, by the client application, a transaction lockdown request.

9. The contactless card authentication method of claim 8 , further comprising disabling, by the client application, a function of the contactless card after receiving the transaction lockdown request.

10. The contactless card authentication method of claim 9 , further comprising enabling, by the client application, the function of the contactless card after receiving the allowance response.

11. The contactless card authentication method of claim 8 , further comprising rejecting any transaction notification not matching the pre-approved transaction.

12. The contactless card authentication method of claim 11 , wherein matching the transaction notification to the pre-approved transaction includes matching a card-present type or a card-not-present type.

13. The contactless card authentication method of claim 8 , further comprising:

receiving, by the client application, a card-present type or a card-not-present type; and

sending, by the client application, the card-present type or the card-not-present type to the authentication server.

14. A contactless card authentication method, comprising:

receiving, by an authentication server, a request from a client application to permit a transaction pre-approval within a time period;

sending, by the authentication server, a transaction notification to the client application;

receiving, by the authentication server, the transaction pre-approval from the client application;

sending, by the authentication server, an allowance response to the client application when the transaction pre-approval is received by the authentication server within the time period or a disallowance response to the client application when the transaction preapproval is received by the authentication server after the time period; and

sending, by the authentication server, a transaction lockdown request to the client application.

15. The contactless card authentication method of claim 14 , wherein the transaction lockdown request instructs the client application to disable a function of the contactless card.

16. The contactless card authentication method of claim 15 , wherein the allowance response instructs the client application to enable the function of the contactless card after sending the allowance response.

17. The contactless card authentication method of claim 14 , further comprising modifying, by the client application, the time period.

18. The contactless card authentication method of claim 14 , further comprising rejecting, by the authentication server, all transactions upon failure to receive the transaction pre-approval within the time period.