Method and device for performing a cryptographic operation
US7822199B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 24, 2005 |
| Grant date | Oct 26, 2010 |
| Priority date | — |
| Expiry date | Nov 18, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2209/56
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A method and device for performing a cryptographic operation by a device controlled by a security application executed outside thereof in which a cryptographic value (y) is produced a calculation comprising at least one multiplication between first and second factors containing a security key (s) associated with the device and a challenge number (c) provided by the security application. The first multiplication factor comprises a determined number of bits (L) in a binary representation and the second factor is constrained in such a way that it comprises, in a binary representation, several bits at 1 with a sequence of at least L−1 bits at 0 between each pair of consecutive bits to 1 while the multiplication is carried out by assembling the binary versions of the first factor shifted according to positions of the bits at 1 of the second factor, respectively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.