Certificate revocation system

• US 6,292,893 B1
• Filed: 01/14/2000
• Issued: 09/18/2001
• Est. Priority Date: 10/24/1995
• Status: Expired due to Term

• Current Assignee: Assa Abloy AB
• Original Assignee: Silvio Micali
• Inventors: Micali, Silvio
• Primary Examiner(s): Swann, Tod
• Assistant Examiner(s): KABAKOFF, STEPHEN ERIC
• Application Number:
  US09/483,125
• Time in Patent Office: 613 Days
• Field of Search: 713/157, 713/158, 713/159, 713/177, 380/30
• US Class Current: 713/158
• CPC Class Codes: G06Q 20/02 involving a neutral party, e.g. certification authority, notary or trusted third party [TTP]
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions
• CPC Class Codes: H04L 9/3268 using certificate validation, registration, distribution or revocation, e.g. certificate revocation list [CRL]
• CPC Class Codes: H04L 9/50 using hash chains, e.g. blockchains or hash trees

Abstract

A certification revocation system uses a one-way function F to verify the validity of a certificate that includes a first value V. Included are means for receiving a second value V′ and means for iterating F on V′ and for comparing the result thereof to V. The function F is used to verify that a certificate having an issue date D and including a first value V is valid at a date belonging to a sequence of dates after D.

Claims

1. A system for using a one-way function F to verify the validity of a certificate that includes a first value V, comprising:

means for receiving a second value V′

; and

means for iterating F on V′ and

for comparing the result thereof to V.

2. A system, according to claim 1, wherein the certificate has an issue date D, the value V′

is received at date D′

, and the number of times F is iterated depends on how many time intervals of a fixed time length occur between D and date D′

.

3. A system, according to claim 1, wherein F is iterated together with one or more additional inputs.

4. A system, according to claim 3, wherein at least one of the one or more additional inputs depends on the certificate.

5. A system, according to claim 2, wherein F is iterated together with one or more additional inputs.

6. A system, according to claim 5, wherein at least one of the one or more additional inputs depends on the certificate.

7. A system for using a one-way function F to verify that a certificate having an issue date D and including a first value V is valid at a date i, belonging to a sequence of dates after D, the system comprising:

means for receiving a second value V′

;

means for computing a value Z=[F{circumflex over ( )}I(V′

)]Fⁱ(V′

); and

means for verifying that Z=[V′

]V.

8. A system, according to claim 7, wherein F is a one-way hash function.

9. A system, according to claim 7, wherein in at least one iteration F has one or more additional inputs.

10. A system, according to claim 9, wherein at least one of the one or more additional inputs depends on the certificate.

11. A system for using functions F1, . . . , Fi, belonging to a sequence of i or more one-way functions, to verify that a certificate having an issue date D and including a final value V is valid at a date i, belonging to a sequence of dates after D, comprising:

means for receiving a second value V′

;

means for computing the value Z1=F1(V′

), Z2=F2(Z1), . . . , Zi=Fi(Zi−

1); and

means for verifying that Zi=[V′

]V.

12. A system, according to claim 11, wherein in at least one function Fj, where j is between 1 and i, is evaluated with one or more additional input.

13. A system, according to claim 12, wherein at least one of the one or more additional inputs depends on at least one of:

the certificate and j.

14. A computer program product stored in a memory, comprising:

means for receiving a certificate that includes a first value V;

means for receiving a second value V′

; and

means for iterating a one-way function F on V′ and

for comparing the result thereof to V.

15. A computer program product, according to claim 14, wherein the certificate has an issue date D, the value V′

is received at date D′

, and the number of times F is iterated depends on how many time intervals of a fixed time length occur between D and date D′

.

16. A computer program product, according to claim 14, wherein F is iterated together with one or more additional inputs.

17. A computer program product, according to claim 16, wherein at least one of the one or more additional inputs depends on the certificate.

18. A computer program product, according to claim 15, wherein F is iterated together with one or more additional inputs.

19. A computer program product, according to claim 18, wherein at least one of the one or more additional inputs depends on the certificate.