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:
Dec. 08, 2020
Filed:
Sep. 20, 2017
Safran Identity & Security, Issy-les-Moulineaux, FR;
Houssem Maghrebi, Issy les Moulineaux, FR;
Guillaume Dabosville, Issy les Moulineaux, FR;
Emmanuel Prouff, Issy les Moulineaux, FR;
IDEMIA IDENTITY & SECURITY FRANCE, Courbevoie, FR;
Abstract
The present invention relates to a method for encryption or decryption of a data block from a secret key, wherein the method comprises: generating a first round key kdependent on the secret key, selecting each of a first mask (−b) and a second mask (−b) in a set consisting of a mask of bits all at one and a mask of all zero bits, calculating a first masked key k' from the first round key kand the first mask (−b) as follows:⊕(−)wherein ⊕ is an exclusive disjunction, executing a first encryption round applied to two first data dependent on the data block, by means of the first masked round key k′ so as to produce two second data, after producing the first masked key k′, generating a second round key kdependent on the secret key, calculating a second masked key k′ from the second round key kand the second mask (−b) as follows: k′=k⊕(−b), calculating two third data L, Ras follows:⊕(−)⊕(−)⊕(−)⊕(−)and executing a second encryption round following the first encryption round, wherein the second encryption round is applied to the two third data L, Rby means of the second masked round key k′.