Fair cryptosystems and methods of use

Patent 5276737 Issued on January 4, 1994. Estimated Expiration Date:

April 20, 2012. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

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Cryptographic system allowing encrypted communication between users with a secure mutual cipher key determined without user interaction Patent #: 5150411
Issued on: 09/22/1992
Inventor: Maurer

Inventor

Micali, Silvio

Application

No. 870935 filed on 04/20/1992

US Classes:

380/30, Public key380/286Key escrow or recovery

Examiners

Primary: Swann, Tod R.

Attorney, Agent or Firm

Judson; David H.

International Class

H04K 001/00

Abstract

A method, using a public-key cryptosystem, for enabling a predetermined entity to monitor communications of users suspected of unlawful activities while protecting the privacy of law-abiding users, wherein each user is assigned a pair of matching secret and public keys. According to the method, each user's secret key is broken into shares. Then, each user provides a plurality of "trustees" pieces of information. The pieces of information provided to each trustee enable that trustee to verify that such information includes a "share" of a secret key of some given public key. Each trustee can verify that the pieces of information provided include a share of the secret key without interaction with any other trustee or by sending messages to the user. Upon a predetermined request or condition, e.g., a court order authorizing the entity to monitor the communications of a user suspected of unlawful activity, the trustees reveal to the entity the shares of the secret key of such user. This enables the entity to reconstruct the secret key and monitor the suspect user's communications.