Bilateral authentication and encryption system

• US 6,105,133 A
• Filed: 12/23/1998
• Issued: 08/15/2000
• Est. Priority Date: 03/10/1997
• Status: Expired due to Term

• Current Assignee: RPX Corporation
• Original Assignee: The PacID Group, LLC (Marathon Patent Group, Inc.)
• Inventors: Fielder, Guy L., Alito, Paul N.
• Primary Examiner(s): Barron, Jr., Gilberto
• Application Number:
  US09/219,967
• Time in Patent Office: 601 Days
• Field of Search: 380/25, 713/169, 713/165, 713/171, 713/283
• US Class Current: 713/169
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying
• CPC Class Codes: H04L 9/3228 One-time or temporary data, i.e. information which is sent for every authentication or authorization, e.g. one-time-password, one-time-token or one-time-key
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions

Abstract

A bilateral system for authenticating remote transceiving stations through use of station identifiers (IDs), and through use of passwords which are used only one time, and thereafter exchanging messages through use of an encryption key which is changed after each system connection. Upon authentication, each of the stations independently creates a secret session encryption key in response to the other station'"'"'s unique station identifier that is exchanged over a communication link in cleartext. The station identifiers are used as tags to look up a unique static secret and a unique dynamic secret which are known only by the two stations, but which are not exchanged over the communication link. The secrets are independently combined by a bit-shuffle algorithm, the result of which is applied to a secure hash function to produce a message digest. The secret session encryption key, a one-time password for the originating station, a one-time password for the receiving station, and a pseudo-random change value for updating the dynamic secret are derived from the message digest. The dynamic secret is updated by the pseudo-random change value and a prime constant after each system connection, thus causing the message digest to be updated upon the occurrence of a new system connection. Further, the system IDs also may be altered by a component of the message digest upon the occurrence of a new system connection to provide an additional protection against playback impersonation.

Claims

1. A network system for secure exchange of files and data, which comprises:

an originating system having stored therein n answering system IDs, n static secrets, n dynamic secrets, a first many-to-few bit mapping program, a second many-to-few bit mapping program, and having means for generating a pseudo-random message digest comprised of an originating system password, a first answering system password, a session encryption key, and a change value by applying said first many-to-few bit mapping program and said second many-to-few bit mapping program to one of said n static secrets and to one of said n dynamic secrets, for verifying authenticity of both an answering system ID through comparison with said n answering system IDs and a second answering system password through comparison with said first answering system password, for generating said pseudo-random message digest and a first acknowledgment of verification upon verification of authenticity of said answering system ID, for altering said one of said n dynamic secrets with said change value upon verification of authenticity of said second answering system password, for decrypting an encrypted answering system password with said session encryption key to provide said second answering system password, encrypting said originating system password to generate an encrypted originating system password, and upon receipt of a second acknowledgment of authenticity verifying said originating system password, encrypting an information file with said session encryption key for transfer over said network system during a system connection;

communication link means in electrical communication with said originating system for accommodating information transfers over said network system; and

an answering system in electrical communication with said communication link means and having stored therein n originating system IDs, said answering system ID, said n static secrets, said n dynamic secrets, said first many-to-few bit mapping program, said second many-to-few bit mapping program, and said means for generating said pseudo-random message digest comprised of said originating system password, said answering system password, said session encryption key, and said change value, and upon verifying authenticity of said originating system ID transferring said answering system ID over said communication link means to said originating system, and upon receiving said first acknowledgment of verification of authenticity of said answering system ID from said originating system over said communication link means, generating said pseudo-random message digest and encrypting said answering system password with said session encryption key to provide said encrypted answering system password over said communication link means to said originating system, and upon receipt of said encrypted originating system password from said originating system by way of said communication link means, decrypting said encrypted originating system password with said session encryption key to verify authenticity of said originating system password, and upon verification of authenticity of said originating system password, issuing said second acknowledgment of authenticity over said communication link means to said originating system.

2. The network system of claim 1, wherein said encryption key is a deterministic, non-predictable, pseudo-random and symmetric encryption key.

3. The network system of claim 1, wherein said first many-to-few mapping program is an algebraic function program.

4. The network system of claim 1, wherein said first many-to-few bit mapping program is a logic function program.

5. The network system of claim 1, wherein said first many-to-few bit mapping program is an encryption program.

6. The network system of claim 1, wherein said first many-to-few bit mapping program consists of plural bit shuffling programs.

7. The network system of claim 1, wherein said second many-to-few bit mapping program is a secure hash algorithm (SHA) function.

8. The network system of claim 1, wherein said second many-to-few bit mapping program is an encryption program.

9. The network system of claim 1, wherein said second many-to-few bit mapping program consists of plural encryption programs.

10. The network system of claim 1, wherein said pseudo-random message digest is used only during a single system connection.

11. A method of providing a secure exchange of information between an originating system having a first system ID and an answering system having a second system ID, and each of said originating system and said answering system having a static secret and a dynamic secret, which comprises:

performing a first bilateral authentication by said originating system and said answering system exchanging and verifying said first system ID and said second system ID;

each of said originating system and said answering system executing a bit-shuffle operand and a secure hash operand with plural bit-mappings to form a pseudo-random message digest from said static secret and said dynamic secret;

each of said originating system and said answering system extracting an originating system password, an answering system password, a deterministic and symmetric encryption key, and a change value from said message digest;

said originating system and said answering system respectively encrypting said originating system password and said answering system password with said deterministic and symmetric encryption key, and respectively transmitting a first encrypted password and a second encrypted password over said communication link;

said answering system and said originating system respectively receiving and decrypting said first encrypted password and said second encrypted password with said deterministic and symmetric encryption key, and respectively verifying said originating system password and said answering system password to perform a second bilateral authentication;

said originating system and said answering system each altering said dynamic secret with said change value and a prime constant;

said originating system and said answering system each encrypting said information with said deterministic and symmetric encryption key, and exchanging encrypted information over said communication link;

said originating system and said answering system repeating immediately above step until all sessions in a system connection between said originating system and said answering system are completed; and

said originating system and said answering system repeating all of the above steps upon either generating a new access request to the other.

12. The method set forth in claim 11 above, wherein said answering system password, said originating system password, said deterministic and symmetric encryption key, and said change value are pseudo-random.

13. The method set forth in claim 11 above, wherein said deterministic and symmetric encryption key is also non-predictable.

14. A method of authenticating an originating system and an answering system in electrical communication by way of a communication link, and protecting information files to be exchanged over said communication link, with minimal contribution to system overhead and system latency, which comprises the steps of:

said originating system transmitting an access request over said communication link to said answering system;

said originating system and said answering system exchanging and verifying system IDs received over said communication link to perform a first bilateral system authentication;

said originating system and said answering system independently combining a static secret and a dynamic secret by executing a first operand which performs a first many-to-few bit mapping to generate a first pseudo-random result;

said originating system and said answering system independently executing a secure hash operand on said first pseudo-random result to perform a second many-to-few bit-mapping and generate a second pseudo-random result;

said originating system and said answering system independently extracting an originating system password, an answering system password, a secret session encryption key, and a change value from said second pseudo-random result;

said originating system transmitting said originating system password over said communication link to said answering system, and verifying said answering system password received over said communication link from said answering system;

said answering system transmitting said answering system password over said communication link to said originating system, and verifying said originating system password received over said communication link from said originating system to perform a second bilateral system authentication;

said originating system and said answering system independently altering said dynamic secret with said change value and a prime constant upon conclusion of a system connection between said originating system and said answering system to generate an updated dynamic secret, and replacing said dynamic secret with said updated dynamic secret; and

said originating system and said answering system independently encrypting said information files through use of said secret session encryption key and transmitting encrypted ones of said information files over said communication link;

repeating immediately above step until all sessions in said system connection are completed, and thereafter repeating all above steps upon either of said originating system and said answering system generating a new access request to the other.

15. The method of claim 14, wherein said dynamic secret, said originating system password, said answering system password, and said secret session encryption key are changed upon completion of said system connection.

16. The method of claim 14, wherein said secret session encryption key is a deterministic, non-predictable, pseudo random, symmetric encryption key.

17. The method of claim 14, wherein said system IDs are used as tags to look up said static secret and said dynamic secret in an originating system memory and an answering system memory.

18. The method set forth in claim 14, wherein said change value is combined with said prime constant to ensure that said dynamic secret is never altered by zero.

19. The method set forth in claim 14, wherein said dynamic secret is changed each time said second bilateral system authentication occurs.

20. A method of authenticating an originating system and an answering system in electrical communication by way of a communication link, and protecting information files to be exchanged over said communication link with minimal contribution to system overhead and system latency, which comprises the steps of:

transmitting an access request and a first system ID from said originating system to said answering system;

verifying said first system ID at said answering system;

transmitting a second system ID from said answering system to said originating system;

verifying said second system ID at said originating system;

transmitting an acknowledgment of verification of said second system ID from said originating system to said answering system;

said originating system and said answering system independently combining a static secret and a dynamic secret with a first function to shuffle all bits in said static secret and said dynamic secret, and perform a first many-to-few bit-mapping to produce a first pseudo-random result;

said originating system and said answering system independently secure hashing said first pseudo-random result with a secure hash algorithm to perform a second many-to-few bit-mapping to produce a second pseudo-random result;

said originating system and said answering system independently extracting an originating system password, an answering system password, a secret session encryption key, and a change value from said second pseudo-random result;

encrypting said answering system password with said secret session encryption key by said answering system to generate a first encrypted password;

transmitting said first encrypted password from said answering system to said originating system;

decrypting and verifying said first encrypted password by said originating system;

encrypting said originating system password with said secret session encryption key by said originating system to generate a second encrypted password;

transmitting said second encrypted password from said originating system to said answering system;

decrypting and verifying said second encrypted password by said answering system;

said originating system and said answering system independently altering said dynamic secret with said change value and a prime constant to produce a second dynamic secret;

said originating system and said answering system each replacing said dynamic secret with said second dynamic secret;

said originating system and said answering system each using said secret session encryption key to encrypt said information files and thereby form encrypted files;

said originating system and said answering system thereafter exchanging said encrypted files; and

upon completion of all sessions occurring during a current system connection, said originating system and said answering system independently repeating all above steps upon either generating a new access request to the other.

21. The method of claim 20, wherein said first system ID, said second system ID, and said dynamic secret are altered each time all authentication cycles for a system connection are completed.

22. A method of authenticating an originating system and an answering system in electrical communication by way of a communication link, and protecting information files to be exchanged over said communication link, which comprises the steps of:

said originating system and said answering system performing a first bilateral authentication by verifying system IDs of said originating system and said answering system;

upon successful completion of said first bilateral authentication, said originating system and said answering system having secret inputs and independently generating therefrom a pseudo-random message digest having an originating system password, an answering system password, a secret session encryption key, and a change value;

said originating system and said answering system performing a second bilateral authentication by respectively encrypting said originating system password and said answering system password with said secret session encryption key, and thereafter exchanging encrypted forms of said originating system password and said answering system password over said communication link for verification;

said originating system and said answering system each altering at least one of said secret inputs with said change value and using said secret session encryption key to encrypt said information files to form encrypted files to be transferred over said communication link during one or more sessions of a system connection; and

said originating system and said answering system each notifying other after each of said one or more sessions whether a new secret session encryption key is required, and if so repeating all but said first bilateral authentication of above steps.

23. The method of claim 22, wherein the step of updating occurs upon completion of a system session.

24. The method of claim 23, further including the step of said originating system and said answering system erasing said originating system password, said answering system password, and said secret session encryption key at end of said system connection.

25. The method of claim 22, wherein said step of updating occurs upon a request being generated by one of said originating system and said answering system.

26. The method of claim 22, wherein the step of said originating system and said answering system having secret inputs and generating therefrom a pseudo-random message digest is repeated n times to create a message digest of increased bit lengths.

27. The method of claim 22, including the step of said originating system and said answering system each altering its system ID when altering at least one of said secret inputs with said change value.