The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 08, 2014
Filed:
Jun. 23, 2009
Olivier Billet, Tourrettes sur Loup, FR;
Ryad Benadjila, Paris, FR;
Olivier Billet, Tourrettes sur Loup, FR;
Ryad Benadjila, Paris, FR;
Orange, Paris, FR;
Abstract
A method and system for a user to obtain a derived value Kof m bits, in which, given two pseudo-random functions gand gfrom m bits to m bits, said user obtains, on the basis of an input parameter consisting of a word r of n bits, a derived value K=g∘ . . . g∘g(S), where, for i=, . . . , n, g=gif r, and g=gif r, and where S is a master value of m bits which is not disclosed to said user. This method comprises the following steps: a search is conducted, from among a set of words of m bits U, where j=, . . . , p, recorded in a table Tand equal to U=g∘ . . . g∘g(S), where, for i=, . . . , l(j), the indices vare predetermined bits, for a word Uequal to U=g∘ . . . g∘g(S); said derived value Kis thereafter obtained by calculating K=g∘ . . . g(U). Application to the encryption/decryption of pay-per-use digital contents, and to authentication.