Public key cryptographic system having nested security levels

• US 5,956,407 A
• Filed: 07/08/1997
• Issued: 09/21/1999
• Est. Priority Date: 11/01/1996
• Status: Expired due to Fees

• Current Assignee: Keith R. Slavin
• Original Assignee: Keith R. Slavin
• Inventors: Slavin, Keith R.
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US08/889,692
• Time in Patent Office: 805 Days
• Field of Search: 380/30
• US Class Current: 380/30
• CPC Class Codes: H04L 9/302 involving the integer factorization problem, e.g. RSA or quadratic sieve [QS] schemes

Abstract

A method of encrypted communication including creating a message and looking up a public key of a recipient. Then, encoding the message via a first encoding process using a first portion of the public key to generated an intermediate encoded message. The intermediate encoded message is encoded via a second encoding process using a second portion of the public key to generate a final encoded message. Then, the final encoded message is sent to a recipient. The public key may have a first key portion, a second key portion, and a third key portion, with the third key portion containing the encoded identity of a data element needed to decode a message encoded with the second key portion. The third key portion is encoded with the public key of a monitoring authority to enable the monitoring authority to more readily decode transmitted messages.

Claims

1. A method of generating a public key comprising the steps:

generating a first key portion by performing a mathematical operation on a first data set;

generating a second key portion by performing a mathematical operation on a second data set;

looking up a public key of a monitoring authority;

generating a third key portion by using the public key of the monitoring authority to encode at least some of the second data set, such that the monitoring authority decrypts messages encoded with the second key portion.

2. The method of claim 1 wherein at least one of the first key portion and the second key portion is the product of at least two prime numbers.

3. The method of claim 2 wherein the third key portion includes an encoded identity of at least one of the prime numbers.

4. The method of claim 1 wherein at least one of generating the first key portion and generating the second key portion includes employing an elliptical algorithm.

5. A method of encrypted communication comprising the steps:

creating a message;

looking up a public key of a recipient;

encoding the message via a first encoding process using a first portion of the public key to generated an intermediate encoded message;

encoding the intermediate encoded message via a second encoding process using a second portion of the public key to generate a final encoded message; and

sending the final encoded message to a recipient.

6. The method of claim 5 including the recipient:

receiving the final encoded message;

decoding the final encoded message to generate the intermediate encoded message;

decoding the intermediate encoded message to generate the final decoded message.

7. The method of claim 5 wherein at least one of the steps of encoding the message via a first encoding process and encoding the intermediate encoded message via a second encoding process includes using an elliptical encryption algorithm.

8. The method of claim 5 wherein at least one of the steps of encoding the message via a first encoding process and encoding the intermediate encoded message via a second encoding process includes using a multiple prime algorithm.

9. The method of claim 5 wherein the steps of encoding the message via a first encoding process and encoding the intermediate encoded message via a second encoding process include using different encryption algorithms.

10. A cryptographic communications system comprising:

a communications network;

a sender terminal connected to the network;

a receiver terminal connected to the network;

a first monitoring authority terminal connected to the network;

a public key repository connected to the network;

the repository containing a first data sequence comprising a receiver encoding key and a second data sequence comprising a first monitoring authority encoding key,

the receiver encoding key comprising a first key portion, a second key portion, and a third key portion,

the first key portion being a functional result of a first data set,

the second key portion being a functional result of a second data set,

the third key portion comprising a numerically encoded result of a mathematical function of the first monitoring authority encoding key and at least a selected portion of the second data set, such that the first monitoring authority decrypts a message encoded with the second key portion.

11. The system of claim 10 wherein the second key portion includes the product of two prime numbers and the third key portion includes the encoded identity of at least one of the prime numbers.

12. The system of claim 10 wherein the first key portion is less than a preselected size established by the monitoring authority.

13. The system of claim 10 including a second monitoring authority terminal connected to the communication line, and wherein the public key repository includes a second monitoring authority public key, and wherein the receiver encoding key includes a fourth encoding key portion comprising a numerically encoded result of a mathematical function of the second monitoring authority encoding key and at least a selected portion of the second data set, such that the second monitoring authority decrypts a message encoded with the second key portion.

14. The system of claim 10 wherein the first monitoring authority is a first governmental body having authority over the jurisdiction in which the sender terminal is located, and the second monitoring authority is a second governmental body having authority over the jurisdiction in which the receiver terminal is located.