Means for identification and exchange of encryption keys

• US 5,307,411 A
• Filed: 09/11/1992
• Issued: 04/26/1994
• Est. Priority Date: 09/12/1991
• Status: Expired due to Term

• Current Assignee: Teliasonera AB
• Original Assignee: Televerket
• Inventors: Anvret, Lena, Mersich, Laszlo
• Primary Examiner(s): Swann, Tod R.
• Application Number:
  US07/943,671
• Time in Patent Office: 592 Days
• Field of Search: 380/18, 380/21, 380/22, 380/30, 380/23, 380/24, 380/25, 380/49, 380/50
• US Class Current: 713/169
• CPC Class Codes: H04L 9/0844 with user authentication or key authentication, e.g. ElGamal, MTI, MQV-Menezes-Qu-Vanstone protocol or Diffie-Hellman protocols using implicitly-certified keys
• CPC Class Codes: H04L 9/3234 involving additional secure or trusted devices, e.g. TPM, smartcard, USB or software token network architectures or network communication protocols for supporting authentication of entities using an additional device in a packet data network H04L63/0853
• CPC Class Codes: H04M 1/66 with means for preventing unauthorised or fraudulent calling verifying user identity or authority in secret or secure digital communications H04L9/32

Abstract

The invention relates to a means for identification and exchange of encryption keys between communicating apparatuses for encrypted transmissions. The means comprises a card reader for smart cards connected to the communication apparatus which may be a telecommunication apparatus, e.g. of telephone or facsimile type. The reader can communicate with another reader at a called telecommunication apparatus. For identification and exchange of encryption keys the required calculations are performed by the reader or the smart card using data stored on the smart card in a protected field with limited access. The means enable intercommunication between products of different makes owing to a standard identification procedure and exchange of encryption keys.

Claims

1. A method of confirming the identity of and the exchange of encryption keys for a communication link between two communication apparatus each having a smart card reader for reading a first smart card at said first smart card reader and a second smart card at said second smart card reader wherein said first smart card reader is operatively coupled to a first communication apparatus and said second smart card reader is operatively coupled to said second communication apparatus comprising the steps of:

performing a read of a secure secret key from a first of said cards;

generating from inside said first smart card an encryption key for said communication link in response to said secure secret key;

providing an authenticating key from a precomputed and prestored value, stored within said first smart card a validation key based upon a secured common authority data base which at one time was common to said first and second smart cards;

authenticating the identity of said first communication apparatus by said second reader by virtue of said authentication key without transmitting the secret key based upon a calculation of said authentication key and information in said second smart card as to a key from said common authority data base;

reversing said performing, generating, providing and authenticating steps to establish the identify and key of said second communication apparatus with said first apparatus;

transmitting the encryption keys after the authentiticy of said first communication apparatus has been established with said second communication apparatus and vice versa; and

establishing a public key/private key communication link based upon the exchanged keys.

2. A method as in claim 1 wherein said establishment step comprises the step of:

sending facsimile data.

3. A method as in claim 1 wherein said step of providing comprises:

transmitting by DTMF tones.

4. A method as in claim 1 wherein said step of providing comprises:

transmitting by modem communication.

5. A method as in claim 1 further comprising the step of:

reading at least one of said smart cards in an reader integral to a telephone set.

6. A method as in claim 1 further comprising the step of:

reading at least one of said smart cards in an reader coupled in parallel with a telephone set.

7. A method as in claim 1 wherein said reversing step occurs concurrently with said first performing, generating, providing and authenticating steps.