Cipher method and system for verifying a decryption of an encrypted user data key

• US 20070160202A1
• Filed: 01/11/2006
• Published: 07/12/2007
• Est. Priority Date: 01/11/2006
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Kelly, Michael, Wilt, Andrew
• Granted Patent: US 7,499,552 B2
• Time in Patent Office: Days
• US Class Current: 380/30
• CPC Class Codes: H04L 9/0825 using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates
• CPC Class Codes: H04L 9/32 including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials

Abstract

A cipher method for verifying a decryption of an encrypted user data key used to encrypt user data prior to an encryption of the user data key with an encryption key. The cipher method involves a decryption of the encrypted user data key with a decryption key in response to an initiation of a decryption of the encrypted user data with the user data key as decrypted with the description key, a decryption of the verification text with the user data key as decrypted with the decryption key, and a validation/invalidation of a use of the user data key as decrypted with the decryption key to decrypt the encrypted user data in response to a matched/unmatched comparison of the verification text as decrypted with the user data key and an intermixing of a known text and a random text.

Claims

1. A signal bearing medium tangibly embodying a program of machine-readable instructions executable by a processor to perform operations for verifying a decryption of an encrypted user data key used to encrypt user data prior to an encryption of the user data key with an encryption key, the operations comprising:

decrypting the encrypted user data key with a decryption key in response to an initiation of a decryption of the encrypted user data with the user data key as decrypted with the description key;

decrypting a verification text with the user data key as decrypted with the decryption key;

validating a use of the user data key as decrypted with the decryption key to decrypt the encrypted user data in response to a matched comparison of the verification text as decrypted with the user data key and an intermixing of a known text and a random text; and

invalidating the use of the user data key as decrypted with the decryption key to decrypt the encrypted user data in response to a mismatched comparison of the verification text as decrypted with the user data key and the intermixing of the known text and the random text.

2. The signal bearing medium of claim 1, wherein the operations further comprise:

encrypting the intermixing of the known text and the random text with the user data key prior to the encryption of the user data key with the encryption key, wherein the verification text is the encrypted intermixing of the known text and the random text.

3. The signal bearing medium of claim 1, wherein the operations further comprise:

segment the intermixing of the known text and the random text;

encrypting the segmented intermixing of the known text and the random text with the user data key prior to the encryption of the user data key with the encryption key, wherein the verification text is the segmented intermixing of the known text and the random text in segments as encrypted with the user data key.

4. The signal bearing medium of claim 1,

wherein the verification text includes a first verification segment, a second verification segment, a third verification segment and a fourth verification segment in sequential order;

wherein the first verification segment includes an encryption of a first random text segment with the user data key prior to the encryption of the user data key with the encryption key;

wherein the second verification segment includes an encryption of a first known text segment with the user data key prior to the encryption of the user data key with the encryption key;

wherein the third verification segment includes an encryption of a second known text segment with the user data key prior to the encryption of the user data key with the encryption key; and

wherein the fourth verification segment includes an encryption of a second random text segment with the user data key prior to the encryption of the user data key with the encryption key.

5. The signal bearing medium of claim 4, wherein the operations further comprise:

encrypting a first grouping of a first known text segment and a first random text segment with the user data key prior to the encryption of the user data key with the encryption key;

encrypting a second grouping of a second known text segment and a second random text segment with the user data key prior to the encryption of the user data key with the encryption key; and

storing the verification text including the encrypted first grouping of the first known text segment and the first random text segment and the encrypted second grouping of the second known text segment and the second random text segment.

6. The signal bearing medium of claim 5, wherein the decrypting of the verification text with the user data key as decrypted with the decryption key includes:

decrypting the first grouping of the first known text segment and the first random text segment with the user data key as decrypted with the decryption key; and

decrypting the second grouping of the second known text segment and the second random text segment with the user data key as decrypted with the decryption key.

7. The signal bearing medium of claim 1,

wherein the encryption key is a public key;

and

wherein the decryption key is a private key.

8. A cipher system, comprising:

a processor; and

a memory storing instructions operable with the processor for verifying a decryption of an encrypted user data key used to encrypt user data prior to an encryption of the user data key with an encryption key, the instructions being executed for;

decrypting the encrypted user data key with a decryption key in response to an initiation of a decryption of the encrypted user data with the user data key as decrypted with the description key;

decrypting a verification text with the user data key as decrypted with the decryption key;

validating a use of the user data key as decrypted with the decryption key to decrypt the encrypted user data in response to a matched comparison of the verification text as decrypted with the user data key and an intermixing of a known text and a random text; and

invalidating the use of the user data key as decrypted with the decryption key to decrypt the encrypted user data in response to a mismatched comparison of the verification text as decrypted with the user data key and the intermixing of the known text and the random text.

9. The cipher system of claim 8, wherein the instructions are further executed for:

encrypting the intermixing of the known text and the random text with the user data key prior to the encryption of the user data key with the encryption key, wherein the verification text is the encrypted intermixing of the known text and the random text.

10. The cipher system of claim 8, wherein the instructions are further executed for:

segmenting the intermixing of the known text and the random text;

encrypting the segmented intermixing of the known text and the random text with the user data key prior to the encryption of the user data key with the encryption key, wherein the verification text is the segmented intermixing of the known text and the random text in segments as encrypted with the user data key.

11. The cipher system of claim 8,

wherein the verification text includes a first verification segment, a second verification segment, a third verification segment and a fourth verification segment in sequential order;

wherein the first verification segment includes an encryption of a first random text segment with the user data key prior to the encryption of the user data key with the encryption key;

wherein the second verification segment includes an encryption of a first known text segment with the user data key prior to the encryption of the user data key with the encryption key;

wherein the third verification segment includes an encryption of a second known text segment with the user data key prior to the encryption of the user data key with the encryption key; and

wherein the fourth verification segment includes an encryption of a second random text segment with the user data key prior to the encryption of the user data key with the encryption key.

12. The cipher system of claim 11, wherein the instructions are further executed for:

encrypting a first grouping of a first known text segment and a first random text segment with the user data key prior to the encryption of the user data key with the encryption key;

encrypting a second grouping of a second known text segment and a second random text segment with the user data key prior to the encryption of the user data key with the encryption key; and

storing the verification text including the encrypted first grouping of the first known text segment and the first random text segment and the encrypted second grouping of the second known text segment and the second random text segment.

13. The cipher system of claim 12, wherein the decrypting of the verification text with the user data key as decrypted with the decryption key includes:

decrypting the first grouping of the first known text segment and the first random text segment with the user data key as decrypted with the decryption key; and

decrypting the second grouping of the second known text segment and the second random text segment with the user data key as decrypted with the decryption key.

14. The cipher system of claim 8,

wherein the encryption key is a public key;

and

wherein the decryption key is a private key.

15. A cipher method for verifying a decryption of an encrypted user data key used to encrypt user data prior to an encryption of the user data key with an encryption key, the cipher method comprising:

decrypting the encrypted user data key with a decryption key in response to an initiation of a decryption of the encrypted user data with the user data key as decrypted with the description key;

decrypting a verification text with the user data key as decrypted with the decryption key;

validating a use of the user data key as decrypted with the decryption key to decrypt the encrypted user data in response to a matched comparison of the verification text as decrypted with the user data key and an intermixing of a known text and a random text; and

invalidating the use of the user data key as decrypted with the decryption key to decrypt the encrypted user data in response to a mismatched comparison of the verification text as decrypted with the user data key and the intermixing of the known text and the random text.

16. The cipher method of claim 15, further comprising:

encrypting the intermixing of the known text and the random text with the user data key prior to the encryption of the user data key with the encryption key, wherein the verification text is the encrypted intermixing of the known text and the random text.

17. The cipher method of claim 15, further comprising:

segment the intermixing of the known text and the random text;

encrypting the segmented intermixing of the known text and the random text with the user data key prior to the encryption of the user data key with the encryption key, wherein the verification text is the segmented intermixing of the known text and the random text in segments as encrypted with the user data key.

18. The cipher method of claim 15,

wherein the verification text includes a first verification segment, a second verification segment, a third verification segment and a fourth verification segment in sequential order;

wherein the first verification segment includes an encryption of a first random text segment with the user data key prior to the encryption of the user data key with the encryption key;

wherein the second verification segment includes an encryption of a first known text segment with the user data key prior to the encryption of the user data key with the encryption key;

wherein the third verification segment includes an encryption of a second known text segment with the user data key prior to the encryption of the user data key with the encryption key; and

wherein the fourth verification segment includes an encryption of a second random text segment with the user data key prior to the encryption of the user data key with the encryption key.

19. The cipher method of claim 18, further comprising:

encrypting a first grouping of a first known text segment and a first random text segment with the user data key prior to the encryption of the user data key with the encryption key;

encrypting a second grouping of a second known text segment and a second random text segment with the user data key prior to the encryption of the user data key with the encryption key; and

storing the verification text including the encrypted first grouping of the first known text segment and the first random text segment and the encrypted second grouping of the second known text segment and the second random text segment.

20. The cipher method of claim 19, wherein the decrypting of the verification text with the user data key as decrypted with the decryption key includes:

decrypting the first grouping of the first known text segment and the first random text segment with the user data key as decrypted with the decryption key; and

decrypting the second grouping of the second known text segment and the second random text segment with the user data key as decrypted with the decryption key.

21. The cipher method of claim 15,

wherein the encryption key is a public key;

and

wherein the decryption key is a private key.