Granted Patent B2

US 12,348,612 · App. 18/241,491 · Granted Jul 1, 2025

Inventors: Sivanarayana Gaddam (Santa Clara, CA); Yogesh Lokhande (Kada Agrahara, IN); Biju Abraham (Fremont, CA)

Assignee: Visa International Service Association

H04L9/0822H04L9/0643H04L9/30

Abstract

Claims (107)

1. A computer-implemented method, comprising:

receiving, with at least one processor, from a hardware security module (HSM), a plurality of random keys (r 1 , r 2 , . . . r n );

generating, with at least one processor, based on a generator function (g) and the plurality of random keys (r 1 , r 2 , . . . r n ), a plurality of public keys (PK 1 , PK 2 , . . . PK n );

generating, with at least one processor, based on a hash function (H) and the plurality of public keys (PK 1 , PK 2 , . . . PK n ), a plurality of secret keys (SK 1 , SK 2 , . . . SK n ) that correspond to the plurality of public keys (PK 1 , PK 2 , . . . PK n );

providing, with at least one processor, to the HSM, the plurality of secret keys (SK 1 , SK 2 , . . . SK n );

receiving, with at least one processor, from the HSM, the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) encrypted with a key encryption key (KEK) as a plurality of ciphers (C 1 , C 2 , . . . C n );

storing, with at least one processor, in memory, the plurality of ciphers (C 1 , C 2 , . . . C n ) in association with the plurality of public keys (PK 1 , PK 2 , . . . PK n ), wherein the plurality of ciphers (C 1 , C 2 , . . . C n ) includes the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) encrypted with the KEK, and wherein the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) correspond to the plurality of public keys (PK 1 , PK 2 , . . . PK n ); and

after storing, in the memory, the plurality of ciphers (C 1 , C 2 , . . . C n ) in association with the plurality of public keys (PK 1 , PK 2 , . . . PK n ), deleting, with at least one processor, the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) and the plurality of random keys (r 1 , r 2 , . . . r n ).

2. The computer-implemented method of claim 1 , further comprising:

receiving, with at least one processor, a data chunk (M i ) for encryption;

generating, with at least one processor, a data encryption key (DEK) based on the hash function (H), a public key (PK i ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ), and a random number (R);

encrypting, with at least one processor, the data chunk (M i ) with the DEK to generate an encrypted data chunk (C Mi );

generating, with at least one processor, a header (Hdr) including a cipher (C i ) of the plurality of ciphers (C 1 , C 2 , . . . C n ) corresponding to the public key (PK i ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ) and key encapsulation data;

storing, with at least one processor, in a database, a cipher text (CT) including the header (Hdr) and the encrypted data chunk (C Mi );

receiving, with at least one processor, a request to decrypt the cipher text (CT);

in response to receiving a request to decrypt the cipher text (CT), providing, with at least one processor, to the HSM, the cipher (C i );

receiving, with at least one processor, from the HSM, a secret key (SK i ) of the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) that corresponds to the public key (PK i ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ) used to generate the DEK used to generate the encrypted data chunk (C Mi );

deriving, with at least one processor, based on the secret key (SK i ) received from the HSM and the key encapsulation data, the DEK used to generate the encrypted data chunk (C Mi ); and

providing, with at least one processor, the derived DEK for decrypting the encrypted data chunk (C Mi ) to obtain the data chunk (M i ).

3. The computer-implemented method of claim 2 , wherein the key encapsulation data includes the hash of the public key H(PK i ), the cipher (C i ), a generator function of the random number g R , and the hash of the corresponding public key raised to a power of the hash of the DEK H(PK i ) H(DEK) .

4. The computer-implemented method of claim 2 , further comprising:

receiving, with at least one processor, a further data chunk (M 1 ) for encryption;

generating, with at least one processor, a further data encryption key (DEK′) based on the hash function (H), a further public key (PK j ) of the plurality of public keys (PK i , PK 2 , . . . PK n ), and a further random number (R);

encrypting, with at least one processor, the further data chunk (M 1 ) with the further DEK′ to generate a further encrypted data chunk (C Mj );

generating, with at least one processor, a further header (Hdr′) including a further cipher (C i ) of the plurality of ciphers (C 1 , C 2 , . . . C n ) corresponding to the further public key (PK j ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ) and further key encapsulation data;

storing, with at least one processor, in the database, a further cipher text (CT′) including the further header (Hdr′) and the further encrypted data chunk (C Mj );

receiving, with at least one processor, a request to decrypt the further cipher text (CT′);

in response to receiving a request to decrypt the further cipher text (CT′), providing, with at least one processor, to the HSM, the further cipher (C i );

receiving, with at least one processor, from the HSM, a further secret key (SK 1 ) of the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) that corresponds to the further public key (PK j ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ) used to generate the further DEK′ used to generate the further encrypted data chunk (C Mj );

deriving, with at least one processor, based on the further secret key (SK j ) received from the HSM and the further key encapsulation data, the further DEK′ used to generate the further encrypted data chunk (C Mj ); and

providing, with at least one processor, the further derived DEK for decrypting the further encrypted data chunk (C Mj ) to obtain the further data chunk (M 1 ).

5. The computer-implemented method of claim 4 , further comprising:

generating, with at least one processor, a token based on the secret key (SK i ) and the further secret key (SK 1 );

deriving, with at least one processor, based on the token and the key encapsulation data, the DEK; and

deriving, with at least one processor, based on the token and the further key encapsulation data, the further DEK′.

6. A system, comprising:

a memory;

one or more processors coupled to the memory and programmed and/or configured to:

receive, from a hardware security module (HSM), a plurality of random keys (r 1 , r 2 , . . . r n );

generate, based on a generator function (g) and the plurality of random keys (r 1 , r 2 , . . . r n ), a plurality of public keys (PK 1 , PK 2 , . . . PK n );

generating, with at least one processor, based on a hash function (H) and the plurality of public keys (PK 1 , PK 2 , . . . PK n ), a plurality of secret keys (SK 1 , SK 2 , . . . SK n ) that correspond to the plurality of public keys (PK 1 , PK 2 , . . . PK n );

provide, to the HSM, the plurality of secret keys (SK 1 , SK 2 , . . . SK n );

receive, from the HSM, the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) encrypted with a key encryption key (KEK) as a plurality of ciphers (C 1 , C 2 , . . . C n );

store, in the memory, the plurality of ciphers (C 1 , C 2 , . . . C n ) in association with the plurality of public keys (PK 1 , PK 2 , . . . PK n ), wherein the plurality of ciphers (C 1 , C 2 , . . . C n ) includes the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) encrypted with the KEK, and wherein the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) correspond to the plurality of public keys (PK 1 , PK 2 , . . . PK n ); and

after storing, in the memory, the plurality of ciphers (C 1 , C 2 , . . . C n ) in association with the plurality of public keys (PK 1 , PK 2 , . . . PK n ), delete, the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) and the plurality of random keys (r 1 , r 2 , . . . r n ).

7. The system of claim 6 , wherein the one or more processors are further programmed and/or configured to:

receive a data chunk (M i ) for encryption;

generate a data encryption key (DEK) based on the hash function (H), a public key (PK i ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ), and a random number (R);

encrypt the data chunk (M i ) with the DEK to generate an encrypted data chunk (C Mi );

generate a header (Hdr) including a cipher (C i ) of the plurality of ciphers (C 1 , C 2 , . . . C n ) corresponding to the public key (PK i ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ) and key encapsulation data;

store, in a database, a cipher text (CT) including the header (Hdr) and the encrypted data chunk (C Mi );

receive a request to decrypt the cipher text (CT);

in response to receiving a request to decrypt the cipher text (CT), provide, to the HSM, the cipher (C i );

receive, from the HSM, a secret key (SK i ) of the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) that corresponds to the public key (PK i ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ) used to generate the DEK used to generate the encrypted data chunk (C Mi );

derive, based on the secret key (SK i ) received from the HSM and the key encapsulation data, the DEK used to generate the encrypted data chunk (C Mi ); and

provide the derived DEK for decrypting the encrypted data chunk (C Mi ) to obtain the data chunk (M i ).

8. The system of claim 7 , wherein the key encapsulation data includes the hash of the public key H(PK i ), the cipher (C i ), a generator function of the random number g R , and the hash of the corresponding public key raised to a power of the hash of the DEK H(PK i ) H(DEK) .

9. The system of claim 7 , wherein the one or more processors are further programmed and/or configured to:

receive a further data chunk (M 1 ) for encryption;

generate a further data encryption key (DEK′) based on the hash function (H), a further public key (PK j ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ), and a further random number (R);

encrypt the further data chunk (M j ) with the further DEK′ to generate a further encrypted data chunk (C Mj );

generate a further header (Hdr′) including a further cipher (C i ) of the plurality of ciphers (C 1 , C 2 , . . . C n ) corresponding to the further public key (PK j ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ) and further key encapsulation data;

store, in the database, a further cipher text (CT′) including the further header (Hdr′) and the further encrypted data chunk (C Mj );

receive, a request to decrypt the further cipher text (CT′);

in response to receiving a request to decrypt the further cipher text (CT′), provide, to the HSM, the further cipher (C i );

receive, from the HSM, a further secret key (SK 1 ) of the plurality of secret keys (SK i , SK 2 , . . . SK n ) that corresponds to the further public key (PK j ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ) used to generate the further DEK′ used to generate the further encrypted data chunk (C Mj );

derive, based on the further secret key (SK j ) received from the HSM and the further key encapsulation data, the further DEK′ used to generate the further encrypted data chunk (C Mj ); and

provide the further derived DEK for decrypting the further encrypted data chunk (C Mj ) to obtain the further data chunk (M 1 ).

10. The system of claim 9 , wherein the one or more processors are further programmed and/or configured to:

generate a token based on the secret key (SK i ) and the further secret key (SK j );

derive, based on the token and the key encapsulation data, the DEK; and

derive, based on the token and the further key encapsulation data, the further DEK′.

11. A computer program product comprising at least one non-transitory computer-readable medium including program instructions that, when executed by at least one processor, cause the at least one processor to:

receive, from a hardware security module (HSM), a plurality of random keys (r 1 , r 2 , . . . r n );

generate, based on a generator function (g) and the plurality of random keys (r 1 , r 2 , . . . r n ), a plurality of public keys (PK 1 , PK 2 , . . . PK n );

generating, with at least one processor, based on a hash function (H) and the plurality of public keys (PK 1 , PK 2 , . . . PK n ), a plurality of secret keys (SK 1 , SK 2 , . . . SK n ) that correspond to the plurality of public keys (PK 1 , PK 2 , . . . PK n );

provide, to the HSM, the plurality of secret keys (SK 1 , SK 2 , . . . SK n );

receive, from the HSM, the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) encrypted with a key encryption key (KEK) as a plurality of ciphers (C 1 , C 2 , . . . C n );

store, in memory, the plurality of ciphers (C 1 , C 2 , . . . C n ) in association with the plurality of public keys (PK 1 , PK 2 , . . . PK n ), wherein the plurality of ciphers (C 1 , C 2 , . . . C n ) includes the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) encrypted with the KEK, and wherein the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) correspond to the plurality of public keys (PK 1 , PK 2 , . . . PK n ); and

after storing, in the memory, the plurality of ciphers (C 1 , C 2 , . . . C n ) in association with the plurality of public keys (PK 1 , PK 2 , . . . PK n ), delete, the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) and the plurality of random keys (r 1 , r 2 , . . . r n ).

12. The computer program product of claim 11 , wherein the instructions further cause the at least one processor to:

receive a data chunk (M i ) for encryption;

generate a data encryption key (DEK) based on the hash function (H), a public key (PK i ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ), and a random number (R);

encrypt the data chunk (M i ) with the DEK to generate an encrypted data chunk (C Mi );

generate a header (Hdr) including a cipher (C i ) of the plurality of ciphers (C 1 , C 2 , . . . C n ) corresponding to the public key (PK i ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ) and key encapsulation data;

store, in a database, a cipher text (CT) including the header (Hdr) and the encrypted data chunk (C Mi );

receive a request to decrypt the cipher text (CT);

in response to receiving a request to decrypt the cipher text (CT), provide, to the HSM, the cipher (C i );

receive, from the HSM, a secret key (SK i ) of the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) that corresponds to the public key (PK i ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ) used to generate the DEK used to generate the encrypted data chunk (C Mi );

derive, based on the secret key (SK i ) received from the HSM and the key encapsulation data, the DEK used to generate the encrypted data chunk (C Mi ); and

provide the derived DEK for decrypting the encrypted data chunk (C Mi ) to obtain the data chunk (M i ).

13. The computer program product of claim 12 , wherein the key encapsulation data includes the hash of the public key H(PK i ), the cipher (C i ), a generator function of the random number g R , and the hash of the corresponding public key raised to a power of the hash of the DEK H(PK i ) H(DEK) .

14. The computer program product of claim 12 , wherein the instructions further cause the at least one processor to:

receive a further data chunk (M 1 ) for encryption;

generate a further data encryption key (DEK′) based on the hash function (H), a further public key (PK j ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ), and a further random number (R);

encrypt the further data chunk (M j ) with the further DEK′ to generate a further encrypted data chunk (C Mj );

generate a further header (Hdr′) including a further cipher (C i ) of the plurality of ciphers (C 1 , C 2 , . . . C n ) corresponding to the further public key (PK j ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ) and further key encapsulation data;

store, in the database, a further cipher text (CT′) including the further header (Hdr′) and the further encrypted data chunk (C Mj );

receive, a request to decrypt the further cipher text (CT′);

in response to receiving a request to decrypt the further cipher text (CT′), provide, to the HSM, the further cipher (C 1 );

receive, from the HSM, a further secret key (SK 1 ) of the plurality of secret keys (SK 1 , SK 2 , . . . SK n ) that corresponds to the further public key (PK j ) of the plurality of public keys (PK 1 , PK 2 , . . . PK n ) used to generate the further DEK′ used to generate the further encrypted data chunk (C Mj );

derive, based on the further secret key (SK 1 ) received from the HSM and the further key encapsulation data, the further DEK′ used to generate the further encrypted data chunk (C Mj ); and

provide the further derived DEK for decrypting the further encrypted data chunk (C Mj ) to obtain the further data chunk (M 1 ).

15. The computer program product of claim 12 , wherein the instructions further cause the at least one processor to:

generate a token based on the secret key (SK i ) and the further secret key (SK 1 );

derive, based on the token and the key encapsulation data, the DEK; and

derive, based on the token and the further key encapsulation data, the further DEK′.

Assignments (1)

Continuity (2)

References Cited (22)