Public key encryption for groups

• US 8,437,474 B2
• Filed: 11/16/2010
• Issued: 05/07/2013
• Est. Priority Date: 12/22/2003
• Status: Active Grant

• Current Assignee: Wells Fargo Bank NA (Wells Fargo & Company)
• Original Assignee: Wells Fargo Bank NA (Wells Fargo & Company)
• Inventors: Zheng, Yuliang, Suarez, Luis Antonio
• Primary Examiner(s): CHEN, SHIN HON
• Application Number:
  US12/947,521
• Publication Number:
  US 20110058673A1
• Time in Patent Office: 903 Days
• Field of Search: None
• US Class Current: 380/255
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 9/0833 involving conference or group key network architectures or network communication protocols for key management in group communication in a packet data network H04L63/065
• CPC Class Codes: H04L 9/302 involving the integer factorization problem, e.g. RSA or quadratic sieve [QS] schemes
• CPC Class Codes: H04L 9/3213 using tickets or tokens, e.g. Kerberos network architectures or network communication protocols for entities authentication using tickets in a packet data network H04L63/0807

Abstract

A system is comprised of a user and a group, wherein the group is comprised of a group leader and a group of M members where M is equal to or greater than one. The group leader generates a group public key and a group leader “master” private key. The group leader creates a personalized watermarked or decryption key, also referred to as an individual private key, for each group member. The individual private key uniquely identifies each group member. The group leader distributes the individual private keys to each of the group members. Each group member receives from a user a message encrypted using the group public key. Each of the group members uses its individual private key to decrypt the encrypted message sent by the user to the group.

Claims

1. A system for public key encryption for groups, the system comprising:

a user, and

a group comprised of a group leader and at least one group member,

wherein the group has a single public key for the group and an individual private key for each group member, the individual private key having been created for each group member according to formula (5);

d_i=d+HASH₃₂(d,N,e,ID_i,Z)φ

(N) 

 

(5)

wherein

d_i is the individual private key for group member i where i equals 1 to M,

M is the number of members in the group,

d is a private exponent,

e is a public exponent,

p is a prime number,

q is a prime number,

ID_i is the identification for group member i,

Z is a data string that is shared among all group members,

N=p*q, and

φ

(N) is=(p−

1)(q−

1)

and

a message received by the group from the user encrypted by asymmetric encryption using the group public key.

2. The system according to claim 1, wherein the system is a computer network system.

3. The system according to claim 2, wherein the computer network system is for banking, investing, or retail services.

4. The system according to claim 1, wherein the single public key and individual private keys are generated by the group leader.

5. The system according to claim 4, wherein the single public key and individual private keys are generated using asymmetric encryption.

6. The system according to claim 5, wherein the asymmetric encryption is selected from the group consisting of RSA, Rabin, variants of RSA, and variants of Rabin.

7. The system according to claim 6, wherein the asymmetric encryption is RSA.