Electronic cryptographic packing

• US 5,995,625 A
• Filed: 03/24/1997
• Issued: 11/30/1999
• Est. Priority Date: 03/24/1997
• Status: Expired due to Term

• Current Assignee: Certco
• Original Assignee: Certco
• Inventors: Kravitz, David W., Sudia, Frank W., Asay, Alan, Brickell, Ernest F., Ankney, Richard, Freund, Peter C., Yung, Marcel M.
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US08/822,732
• Time in Patent Office: 981 Days
• Field of Search: 380/4, 380/25
• US Class Current: 705/51
• CPC Class Codes: G06F 21/6209 to a single file or object, e.g. in a secure envelope, encrypted and accessed using a key, or with access control rules appended to the object itself
• CPC Class Codes: G06F 2211/007 Encryption, En-/decode, En-/decipher, En-/decypher, Scramble, (De-)compress
• CPC Class Codes: G06F 2211/008 Public Key, Asymmetric Key, Asymmetric Encryption
• CPC Class Codes: G06F 2221/2115 Third party

Abstract

A method of unwrapping wrapped digital data that is unusable while wrapped, includes obtaining an acceptance phrase from a user; deriving a cryptographic key from the acceptance phrase; and unwrapping the package of digital data using the derived cryptographic key. The acceptance phrase is a phrase entered by a user in response to information provided to the user. The information and the acceptance phrase can be in any appropriate language. The digital data includes, alone or in combination, any of: software, a cryptographic key, an identifying certificate, an authorizing certificate, a data element or field of an identifying or authorizing certificate, a data file representing an images, data representing text, numbers, audio, and video.

Claims

1. A method of providing wrapped digital data that is unusable while wrapped, the method comprising:

providing first digital data to be wrapped;

providing second digital data comprising data representing conditions of use of the first digital data;

determining an acceptance phrase to indicate acceptance of the conditions;

deriving a wrapping key from at least digital data representing the acceptance phrase and from the second digital data; and

wrapping the first digital data using the wrapping key.

2. A method as in claim 1, wherein the second digital data further comprises a random value.

3. A method as in claim 1 wherein the deriving the key comprises obtaining a digest of digital data representing the acceptance phrase.

4. A method as in claim 3 wherein the obtaining of the digest comprises hashing the digital data representing the acceptance phrase.

5. A method as in claim 1 wherein the first digital data comprises data representing at least one of:

software, a cryptographic key, the root key in a public key infrastructure, an identifying certificate, an authorizing certificate, a data file representing an image, data representing text, numbers, audio, and video.

11. A method as in claim 1 wherein the first digital data is a subscriber'"'"'s public key in a public key infrastructure, and wherein the digital data representing the wrapped subscriber'"'"'s public key is stored in a digital certificate issued to the subscriber.

14. A method as in claim 1 further comprising:

a certification authority issuing to a subscriber digital data representing a digital certificate;

forming, as said first digital data, a hash value of the content of the digital data representing the subscriber'"'"'s digital certificate;

by the certification authority, digitally signing the wrapped hash value; and

appending the digital data representing the digitally signed wrapped hash value to the certificate content.

32. A method as in claim 1 wherein the first digital data contains an embedded glyph value and wherein the second digital data further comprises a function of the glyph value.

33. A method as in claim 32 wherein the function of the glyph value is provided with the wrapped data.

34. A method as in claim 1 wherein the function of the glyph value is selected from a keyed hash function and a cryptographic hash function.

36. A method as in claim 1 wherein said second digital data comprises data representing said conditions for each of a plurality of different languages and wherein said wrapping key is derived from a hash value of the conditions in each of the languages.

37. A method as in claim 36 wherein the wrapping key is derived from a plurality of different acceptance phrases corresponding to each of the plurality of different languages.

6. A method of unwrapping wrapped digital data such that the wrapped data is unusable while wrapped and such that the wrapped data must be unwrapped by a key formed from a particular acceptance phrase, the method comprising:

obtaining second digital data comprising conditions of use of the wrapped digital data;

obtaining the particular acceptance phrase, the phrase indicating acceptance of the conditions;

generating a key from at least the digital data representing the acceptance phrase and the second digital data; and

unwrapping the wrapped digital data using the key.

7. A method as in claim 6, wherein the second digital data further comprises a random value.

8. A method as in claim 7 wherein the deriving of the cryptographic key comprises obtaining a digest of digital data representing the acceptance phrase.

9. A method as in claim 8 wherein the obtaining of the digest comprises hashing the digital data representing the acceptance phrase.

10. A method as in claim 9 wherein the acceptance phrase is obtained in response to displaying the conditions to the user.

12. A method as in claim 6 wherein the first digital data is a subscriber'"'"'s public key in a public key infrastructure, and wherein digital data representing the wrapped subscriber'"'"'s public key is stored in a digital certificate issued to the subscriber.

13. A method as in claim 12 further comprising using the unwrapped digital data to verify the subscriber'"'"'s digital signature on a digitally signed message.

15. A method as in claim 6 further comprising:

a certification authority issuing to a subscriber digital data representing a digital certificate;

forming a hash value of the digital data representing the content of the subscriber'"'"'s digital certificate;

wrapping the hash value with the key;

verifying a wrapped digital signature on the digital certificate using the wrapped hash value and a public key of the certification authority.

35. A method as in claim 6 wherein the digital data contains an embedded glyph value and wherein the second digital data further comprises a function of the glyph value.

38. A method as in claim 6 wherein said second digital data comprises data representing said conditions for each of a plurality of different languages and wherein said wrapping key is derived from a hash value of the conditions in each of the languages.

39. A method as in claim 38 wherein the wrapping key is derived from a plurality of different acceptance phrases corresponding to each of the plurality of different languages.

40. A method as in claim 39 further comprising:

selecting a particular language; and

determining a user'"'"'s competence in the particular language, wherein

the particular acceptance phrase is obtained for the particular language.

16. A method of providing digital data representing a digital identification certificate in a public key infrastructure wherein a certification authority issues identification certificates to subscribers, the method comprising:

providing first digital data representing a subscriber public cryptographic key for a subscriber;

providing second digital data comprising conditions of use of the subscriber public cryptographic key;

determining an acceptance phrase to indicate acceptance of the conditions;

determining a wrapping key value based on at least the digital data representing the particular acceptance phrase and on the second digital data;

encrypting the digital data representing the subscriber public key using the wrapping key; and

providing the digital data representing the encrypted subscriber public key in the certificate.

17. A method as in claim 16 wherein the determining of the wrapping key comprises:

hashing the digital data representing the acceptance phrase;

hashing the first digital data; and

combining the hashes of the first digital data and of the digital data representing the acceptance phrase to form the wrapping key.

18. A method as in claim 17 wherein the combining further comprises combining the hashes with a random value to form the wrapping key.

19. A method as in claim 18 further comprising:

when the wrapping key value is determined using a random value, storing digital data representing the random value as a field in the certificate.

20. A method as in claim 17 wherein the combining further comprises combining data from the certificate to form the wrapping key.

21. A method as in claim 20 wherein the data from the certificate includes at least one of a certificate number and a name of the certificate issuer.

22. A method of verifying a digital signature in a public key infrastructure wherein a certification authority (CA) issues an identification certificate to a subscriber, the certificate including a version of the subscriber'"'"'s public key encrypted with a wrap key formed using at least digital data representing conditions of the CA and digital data representing a particular assent phrase, the method of a relying party comprising:

verifying the CA'"'"'s digital signature on the certificate;

obtaining digital data representing the conditions of the CA;

inputting an acceptance phrase indicating acceptance of the conditions;

determining an unwrap cryptographic key from a first function of the digital data representing the conditions and from a second function of digital data representing the acceptance phrase;

decrypting the encrypted subscriber'"'"'s public key using the unwrap cryptographic key; and

verifying the digital signature using the subscriber'"'"'s public key.

23. A method as in claim 22 wherein at least one of the first function and the second function is a hash function.

24. A method as in claim 22 wherein the subscriber'"'"'s public key is encrypted with a key formed from at least digital data representing conditions of the CA, digital data representing a particular assent phrase and a random value, and wherein the random value is stored in the subscriber'"'"'s digital certificate, wherein determining of the unwrap cryptographic key comprises:

combining a hash of the digital data representing the conditions, a hash of the digital data representing the acceptance phrase and a function of the random value.

25. A method as in claim 23 wherein the function of the random value is the random value itself.

26. A method of providing a digital identification certificate in a public key infrastructure wherein a certification authority (CA) issues the identification certificate to a subscriber, the method comprising:

determining a wrapping key value based on at least digital data representing a particular acceptance phrase and digital data representing conditions of the CA;

hashing the content of the certificate;

encrypting the hashed content of the certificate using the wrapping key value to form a wrapped hashed content value;

digitally signing the wrapped hashed content value using a private key of the CA to form a signature; and

appending the signature to the certificate.

27. A method of verifying a digital signature in a public key infrastructure wherein a certification authority (CA) issues an identification certificate to a subscriber, an encrypted hash of the certificate being digitally signed by the CA, the hash being encrypted with a wrap key formed from conditions of the CA and digital data representing a particular assent phrase, the method by a relying party comprising:

obtaining digital data representing the conditions of the CA;

inputting an acceptance phrase in response to said obtaining;

determining an wrapping cryptographic key value from at least a hash of digital data representing the digital data representing the conditions and a hash of the digital data representing the acceptance phrase;

wrapping a hash of the content of the certificate using the wrapping key value to form a wrapped hashed content value;

verifying the CA'"'"'s digital signature using the wrapped hashed content and a public key of the CA.

28. A method of forming a digital signature on a digital message in a public key infrastructure wherein a certification authority (CA) issues a certificate to a subscriber, the method comprising:

obtaining digital data representing conditions to be accepted by a relying party;

determining an acceptance phrase;

hashing the digital message;

encrypting the hashed digital message using a cryptographic key value formed from at least a hash of the digital data representing the conditions to be accepted and a hash of the digital data representing the acceptance phrase;

forming a subscriber signature for the message by digitally signing the encrypted hashed digital message using a private cryptographic key of the subscriber; and

appending the subscriber signature to the message.

29. A method as in claim 28 wherein the certificate issued by the CA is an identification certificate including digital data representing the subscriber'"'"'s public cryptographic key which corresponds to the private cryptographic key used to form the subscriber signature.

30. A method of verifying a digital signature on a digital message in a public key infrastructure wherein a certification authority (CA) issues a certificate to a subscriber, the method by a relying party comprising:

obtaining digital data representing the identity certificate issued to the subscriber by the CA, the certificate including digital data representing the subscriber'"'"'s public key;

obtaining digital data representing conditions of the issuing CA;

inputting an acceptance phrase;

hashing the digital message;

encrypting the hashed digital message using a cryptographic key value formed from at least a hash of the digital data representing the conditions and a hash of digital data representing the acceptance phrase; and

verifying the subscriber'"'"'s signature using the encrypted hash of the digital message.

31. A method of verifying a digital signature on a digital message in a public key infrastructure wherein a certification authority (CA) issues a certificate to a subscriber, said digital signature having been created using a reversible digital signature algorithm, the method by a relying party comprising:

obtaining digital data representing the identity certificate issued to the subscriber by the CA, the certificate including digital data representing the subscriber'"'"'s public key;

obtaining digital data representing conditions of the issuing CA;

inputting an acceptance phrase;

hashing the digital message;

verifying the subscriber'"'"'s signature by using the subscriber'"'"'s public key to reverse the signing process and recover encrypted hash of the digital message;

decrypting the encrypted hash of the digital message recovered from the subscriber'"'"'s signature using a cryptographic key value formed from at least a hash of the digital data representing the conditions and a hash of digital data representing the acceptance phrase;

comparing the decrypted hash of the digital message with the hash of the digital message; and

accepting the digital message as valid only if the two hash values are identical.

41. A method of providing digital data representing a digital identification certificate in a public key infrastructure wherein a certification authority (CA) issues identification certificates to subscribers, the method comprising:

providing first digital data representing a subscriber public cryptographic key for a subscriber;

providing second digital data comprising conditions of use of the subscriber public cryptographic key;

determining an acceptance phrase to indicate acceptance of the conditions;

determining a wrapping key value based on at least the digital data representing the particular acceptance phrase and on the second digital data;

encrypting the digital data representing the subscriber public key using the wrapping key;

inserting the digital data representing the encrypted subscriber public key into a first certificate;

forming a digital signature using the first certificate and a private key of the CA;

inserting the digital data representing the subscriber public key into a second certificate; and

appending the digital signature to the second certificate and providing the second certificate as a digital identification certificate.

42. A method of verifying a digital signature in a public key infrastructure wherein a certification authority (CA) issues an identification certificate to a subscriber, the certificate including the subscriber'"'"'s public key and having a digital signature formed from a different version of the identification certificate, the different version including an encrypted version of the subscriber'"'"'s public key, the method of a relying party comprising:

forming the different version of the certificate; and

verifying the CA'"'"'s digital signature on the different version of the certificate, wherein the forming the different version comprises;

obtaining digital data representing the conditions of the CA;

inputting an acceptance phrase indicating acceptance of the conditions;

determining a cryptographic key from a first function of the digital data representing the conditions and from a second function of digital data representing the acceptance phrase;

encrypting the encrypted subscriber'"'"'s public key using the wrap cryptographic key; and

replacing the subscriber'"'"'s public key in the certificate with the encrypted subscriber'"'"'s public key.