Lucent Technologies Inc.

Alcatel-lucent USA Inc.

Daniel Bleichenbacher

Bjorn Markus Jakobsson

Avishai Wool

A method and apparatus are disclosed for compressing Rabin signatures. The disclosed compression scheme compresses a Rabin signature, s, for a user having a public key, n, based on a continued fraction expansion of s/n. The continued fraction expansion of s/n can be performed by (i) computing principal convergents, u/v, for i equal to 1 to k, of a continued fraction expansion of s/n, where k is a largest integer for which principal convergents are defined; establishing an index l, such that v&#x3c;&#x221a;{square root over (n)}&#x2266;v; and generating a compressed Rabin signature (v, m) for a message, m.

Method and apparatus for compressing rabin signatures

A system for, and method of, controlling access to a resource of a computer system. In one embodiment, the system includes: (1) a database of problems and corresponding precalculated solutions, (2) a problem retriever that responds to a request from a client for access to the resource by retrieving one of the problems from the database and transmitting the one of the problems to the client and (3) a solution evaluator that, upon receiving a putative solution from the client, employs the database to validate the putative solution and, if the putative solution is valid, grants the client access to the resource.

System and method for exacting a system resource access cost

A system for restricting access to transmitted programming content is disclosed, which transmits a program identifier with the encrypted programming content. A set-top terminal or similar mechanism restricts access to the transmitted multimedia information using stored decryption keys. The set-top terminal receives entitlement information periodically from the head-end, corresponding to one or more packages of programs that the customer is entitled to for a given period. Each program is encrypted by the head-end server prior to transmission, using a program key, K , which may be unique to the program. The set-top terminal uses the received program identifier, p, together with the stored entitlement information, to derive the decryption key necessary to decrypt the program. Each of the k-bit program keys, K , used to encrypt transmitted programs is obtained by applying one or more pseudo-random hash functions, H, such as a length-doubling hash function, H, to a master key, m.

Growing community of inventors

Summit, NJ, United States of America

Daniel Bleichenbacher