Granted Patent B2

US 12,603,764 · App. 18/769,927 · Granted Apr 14, 2026

Inventor: Hao Cheng (Oakton, VA)

Assignee: Capital One Services, LLC

H04L9/0825H04L9/0863H04L9/0894H04L9/3213H04L9/3226

Abstract

Claims (81)

1 . A method comprising:

receiving, at a first computing device and from a second computing device, a first time-constraint token;

receiving, at the first computing device, a current system time and a predetermined shared secret associated with the first computing device and the second computing device, wherein the current system time is determined using an epoch converter;

deriving, using a first key derivation function and based on the current system time and the predetermined shared secret, a first cryptographic key;

decrypting, by the first computing device and using the first cryptographic key, the first time-constraint token to recover a public key;

deriving, by the first computing device and based on a first password, a private key;

deriving, by the first computing device and based on the private key and the public key, a second cryptographic key; and

encrypting, by the first computing device and based on the second cryptographic key, data to generate encrypted data.

2 . The method of claim 1 , further comprising at least one of:

storing, by the first computing device, the encrypted data, or

sending, by the first computing device and to the second computing device, the encrypted data.

3 . The method of claim 1 , further comprising:

performing, by the first computing device, an error detection calculation on the data to generate first error detection data; and

combining the data and the first error detection data, wherein encrypting further comprises encrypting the combined data and the first error detection data to generate the encrypted data.

4 . The method of claim 3 , wherein combining further comprises concatenating the data and the first error detection data.

5 . The method of claim 3 , wherein combining further comprises interleaving, according to a predetermined interleaving pattern, the data and the first error detection data.

6 . The method of claim 3 , further comprising encoding, using Base64 encoding, the encrypted data.

7 . The method of claim 1 , wherein decrypting further comprises:

decrypting, based on the first cryptographic key, the first time-constraint token to recover first error detection data.

8 . The method of claim 7 , wherein the method further comprises:

performing, by the first computing device, an error detection calculation on the public key to generate second error detection data;

comparing the first error detection data to the second error detection data; and

determining that the first time-constraint token is valid when the first error detection data matches the second error detection data.

9 . The method of claim 7 , further comprising:

determining that the first time-constraint token is invalid as expired;

modifying the current system time to derive a modified current system time;

deriving, using the first key derivation function and based on the modified current system time and the predetermined shared secret, a modified first cryptographic key; and

decrypting, based on the modified first cryptographic key, the first time-constraint token to recover a modified public key and modified first error detection data.

10 . The method of claim 1 , wherein deriving the private key further comprises:

deriving, using a second key derivation function and based on the first password, a first block of data of a first desired size; and

deriving, using a third key derivation function and based on the first block of data, the private key.

11 . The method of claim 1 , further comprising:

receiving, at the second computing device, a second password;

deriving, using a second key derivation function and based on the second password, a first block of data of a first desired size;

deriving, using a third key derivation function and based on the first block of data, the public key;

performing, by the second computing device, an error detection calculation on the public key to generate error detection data;

combining the public key and the error detection data;

receiving, at the second computing device, the current system time and the predetermined shared secret associated with the first computing device and the second computing device;

deriving, using the first key derivation function and based on the current system time and the predetermined shared secret, the first cryptographic key;

encrypting, using the first cryptographic key, the combined public key and the error detection data, to generate output data;

encoding the output data to form the first time-constraint token; and

sending, from the second computing device and to the first computing device, the first time-constraint token.

12 . The method of claim 1 , further comprising:

receiving, at the second computing device, the encrypted data;

receiving, at the second computing device and from the first computing device, a second time-constraint token;

receiving, at the second computing device, the current system time and the predetermined shared secret associated with the first computing device and the second computing device;

deriving, at the second computing device, using the first key derivation function and based on the current system time and the predetermined shared secret, the first cryptographic key;

decrypting, using the first cryptographic key, the second time-constraint token to recover a second public key;

performing an error detection calculation on the second public key to generate error detection data;

determining that the second time-constraint token is valid based on the error detection data;

deriving, by the second computing device, and based on a second private key and the second public key, a third cryptographic key, wherein the second private key is derived based on a second password;

decrypting, by the second computing device and based on the third cryptographic key, the encrypted data to recover the data; and

storing, by the second computing device, the data.

13 . A computing device comprising: one or more processors; and memory storing instructions that, when executed by the one or more processors, cause the computing device to:

receive, from a second computing device, a first time-constraint token;

receive a current system time and a predetermined shared secret associated with the computing device and the second computing device, wherein the current system time is determined using an epoch converter;

derive, using a first key derivation function and based on the current system time and the predetermined shared secret, a first cryptographic key;

decrypt, using the first cryptographic key, the first time-constraint token to recover a public key;

derive, based on a first password, a private key;

derive, based on the private key and the public key, a second cryptographic key; and

encrypt, based on the second cryptographic key, data to generate encrypted data.

14 . The computing device of claim 13 , wherein the instructions, when executed by the one or more processors, cause the computing device to perform at least one of:

store the encrypted data, or

send, to the second computing device, the encrypted data.

15 . The computing device of claim 13 , wherein the instructions, when executed by the one or more processors, cause the computing device to:

perform an error detection calculation on the data to generate first error detection data; and

combine the data and the first error detection data, wherein encrypting further comprises encrypting the combined data and the first error detection data to generate the encrypted data.

16 . The computing device of claim 13 , wherein the instructions, when executed by the one or more processors, cause the computing device to derive the public key by:

deriving, using a second key derivation function and based on the first password, a first block of data of a first desired size; and

deriving, using a third key derivation function and based on the first block of data, the private key.

17 . One or more non-transitory computer-readable media storing instructions that, when executed by one or more processors, cause the one or more processors to perform steps comprising:

receive, at a first computing device and from a second computing device, a first time-constraint token;

receive, at the first computing device, a current system time and a predetermined shared secret associated with the first computing device and the second computing device, wherein the current system time is determined using an epoch converter;

derive, using a first key derivation function and based on the current system time and the predetermined shared secret, a first cryptographic key;

decrypt, by the first computing device and using the first cryptographic key, the first time-constraint token to recover a public key;

derive, by the first computing device and based on a first password, a private key;

derive, by the first computing device and based on the private key and the public key, a second cryptographic key; and

encrypt, by the first computing device and based on the second cryptographic key, data to generate encrypted data.

18 . The one or more non-transitory computer-readable media of claim 17 , wherein the instructions, when executed by the one or more processors, cause the first computing device to perform at least one of:

store the encrypted data, or

send, to the second computing device, the encrypted data.

Assignments (1)

Continuity (2)

References Cited (11)