System and method for using a second resource to store a data element from a first resource in a first-in last-out stack

• US 6,249,871 B1
• Filed: 06/28/2000
• Issued: 06/19/2001
• Est. Priority Date: 05/21/1997
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Stubblebine, Stuart Gerald, Devanbu, Premkumar Thomas
• Primary Examiner(s): Swann, Tod
• Assistant Examiner(s): KABAKOFF, STEPHEN ERIC
• Application Number:
  US09/604,953
• Time in Patent Office: 356 Days
• Field of Search: 713/156, 713/165, 713/176, 713/178, 713/181, 713/187, 713/200, 713/201, 707/10, 711/132
• US Class Current: 713/176
• CPC Class Codes: G06F 12/1408 by using cryptography for digital transmission H04L9/00
• CPC Class Codes: G06F 21/33 using certificates
• CPC Class Codes: G06F 21/64 Protecting data integrity, e.g. using checksums, certificates or signatures
• CPC Class Codes: G06F 2211/007 Encryption, En-/decode, En-/decipher, En-/decypher, Scramble, (De-)compress
• CPC Class Codes: H04L 9/3247 involving digital signatures

Abstract

A system and method are provided for using a second resource to store a data element from a first resource in a stack. A data element X_N'"'"'1 and a signature S[N] are signed at a first resource to obtain a signature S[X_N+1,S[N]], where N is an integer. The data element X_N+1 and the signature S[N] are sent from the first resource to the second resource to be stored in a stack. The signature S[X_N+1,S[N]] is stored at the first resource.

Claims

1. A method for using a second resource to store a data element from a first resource, comprising the steps of:

signing a data element X_N+1 and a signature S[N]=S(X_N,S(X<sub>N−

1</sub>, S(X<sub>N−

2</sub>,S( . . . S(X₁,S(initial)) . . . ) at a first resource to obtain a signature S[X_N+1,S[N]], where N is an integer and S(initial) is any arbitrary initial value;

providing the data element X_N+1 and the signature S[N] from the first resource to the second resource; and

storing the signature S[X_N+1,S[N]] at the first resource.

2. The method of claim 1, further comprising the steps of:

obtaining a data element Y and a signature S at the first resource;

signing a combination of the data element Y and the signature S to obtain a signature S′

; and

determining if the signature S′

is the same as the signature S[X_N+1,S[N]].

3. The method of claim 1, further comprising the steps of:

obtaining a data element Y and a signature S at the first resource;

signing the data element Y and the signature S to obtain a signature S′

;

detennining if the signature S′

is the same as the signature S[X_N+1,S[N]]; and

if the signature S′

is the same as the signature S[X_N+1,S[N]], determining that the data element Y is the same as the data element X_N+1.

4. The method of claim 1, further comprising the steps of:

receiving a data element Y and a signature S at the first resource;

signing the data element Y and the signature S to obtain a signature S′

;

determining if the signature S′

is the same as the signature S[X_N+1,S[N]]; and

if the signature S′

is the same as the signature S[X_N+1,S[N]];

determining that the data element Y is the same as the data element X_N+1; and

storing the signature S at the first resource.

5. A method for using a second resource to store a data element from a first resource, comprising the steps of:

obtaining a data element X_N+1 and a signature S[N]=S(X_N,S(X<sub>N−

1</sub>, S(X<sub>N−

2</sub>,S( . . . S(X₁,S(initial)) . . . ) from the first resource at the second resource where S(initial) is any arbitrary initial value; and

storing the data element X_N+1 and a signature S[N] at the second resource.

6. The method of claim 5, further comprising the steps of:

obtaining a request for a data element from the first resource at the second resource; and

providing a data element X_N+1 and a signature S[N] from the second resource to the first resource.

7. An apparatus for storing a data element at a second resource, comprising:

a processor;

a memory that stores instructions adapted to be executed by said processor to sign a data element X_N+1 and a signature S[N]=S(X_N,S(X<sub>N−

1</sub>,S(X<sub>N−

2</sub>, S( . . . S(X₁,S(initial)) . . . ) to obtain a signature S[X_N+1,S[N]], where N is an integer and S(initial) is any arbitrary initial value, provide the data element X_N+1 and the signature S[N] to the second resource, and store the signature S[X_N+1,S[N]] in said memory; and

a port adapted to be coupled to the second resource and through which the data element X_N+1 and signature S[N] are provided to the second resource, said port and said memory coupled to said processor.

8. The apparatus of claim 7, wherein said instructions are further adapted to be executed by said processor to obtain a data element Y and a signature S, sign a combination of the data element Y and the signature S to obtain a signature S′

, and determine if the signature S′

is the same as the signature S[X_N+1,S[N]].

9. The apparatus of claim 7, further comprising a tamper-proof enclosure surrounding said processor and memory.

10. The apparatus of claim 7, wherein said port comprises an electrical interface disposed to conduct electrical signals through a tamper-proof enclosure to said processor.

11. The apparatus of claim 7, wherein said port is adapted to be coupled to the second resource through a network.

12. The apparatus of claim 7, wherein said port is adapted to be coupled to the second resource through a PCMCIA interface.

13. A medium that stores instructions adapted to be executed by a processor to perform the steps of:

signing a data element X_N+1 and a signature S[N]=S(X_N,S(X<sub>N−

1</sub>, S(X<sub>N−

2</sub>,S( . . . S(X₁,S(initial)) . . . ) at a first resource to obtain a signature S[X_N+1,S[N]], where N is an integer and S(initial) is any arbitrary initial value;

providing the data element X_N+1, and the signature S[N] from the first resource to the second resource; and

storing the signature S[X_N+1,S[N]] at the first resource.

14. The medium of claim 13, wherein said instructions are further adapted to be executed by a processor to perform the steps of:

obtaining a data element Y and a signature S at the first resource;

signing a combination of the data element Y and the signature S to obtain a

signature S′

; and

determining if the signature S′

is the same as the signature S[X_N+1,S[N]].

15. The medium of claim 13, wherein said instructions are further adapted to be executed by a processor to perform the steps of:

obtaining a data element Y and a signature S at the first resource;

signing the data element Y and the signature S to obtain a signature S′

;

determining if the signature S′

is the same as the signature S[X_N+1,S[N]]; and

if the signature S′

is the same as the signature S[X_N+1,S[N]], determining that the data element Y is the same as the data element X_N+1.

16. The medium of claim 13, wherein said instructions are further adapted to be executed by a processor to perform the steps of:

obtaining a data element Y and a signature S at the first resource;

signing the data element Y and the signature S to obtain a signature S′

;

determining if the signature S′

is the same as the signature S[X_N+1,S[N]]; and

if the signature S′

is the same as the signature S[X_N+1,S[N]];

determining that the data element Y is the same as the data element X_N+1; and

storing the signature S at the first resource.

17. A system for storing a data element from a first resource at a second resource in a stack, comprising:

means for signing a data element X_N+1 and a signature S[N]=S(X_N,S(X<sub>N−

1</sub>, S(X<sub>N−

2</sub>,S( . . . S(X₁,S(initial)) . . . ) at a first resource to obtain a signature S[X_N+1,S[N]], where N is an integer and S(initial) is any arbitrary initial value;

means for providing the data element X_N+1 and the signature S[N] from the first resource to the second resource; and

means for storing the signature S[X_N+1,S[N]] at the first resource.

18. The system of claim 17, further comprising:

means for obtaining a data element Y and a signature S at the first resource;

means for signing a combination of the data element Y and the signature S to obtain a signature S′

; and

means for determining if the signature S′

is the same as the signature S[X_N+1,S[N]].

19. The system of claim 17, further comprising:

means for obtaining a data element Y and a signature S at the first resource;

means for signing the data element Y and the signature S to obtain a signature S′

;

means for determining if the signature S′

is the same as the signature S[X_N+1,S[N]]; and

means for determining that the data element Y is the same as the data element X_N+1.

20. The system of claim 17, further comprising:

means for obtaining a data element Y and a signature S at the first resource;

means for signing the data element Y and the signature S to obtain a signature S′

;

means for determining if the signature S′

is the same as the signature S[X_N+1,S[N]];

means for detennining that the data element Y is the same as the data element X_N+1; and

means for storing signature S.

21. A method for using a computer to store a data element from a smart card, comprising the steps of:

signing a data element X_N+1 and a signature S[N]=S(X_N,S(X<sub>N−

1</sub>, S(X<sub>N−

2</sub>,S( . . . S(X₁,S(initial)) . . . ) at the smart card to obtain a signature S[X_N+1,S[N]], where N is an integer and S(initial) is any arbitrary initial value;

providing the data element X_N+1 and the signature S[N] from the smart card to the computer; and

storing the signature S[X_N+1,S[N]] at the smart card.