Selection of a lookup table with data masked with a combination of an additive and multiplicative mask
US7970129B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 19, 2007 |
| Grant date | Jun 28, 2011 |
| Priority date | — |
| Expiry date | Apr 27, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2209/046
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Processing of masked data using multiple lookup tables (LUTs), or sub-tables, is described. For each input value, an appropriate sub-table provides an output value that is the result of a non-linear transformation (e.g., byte substitution) applied to the input value. An additive mask can be applied to the input data. A transformation can be applied to the masked input data to transform the additive mask into a multiplicative-additive mask. Selected bits of the masked input data and the bits in the additive component of the multiplicative-additive mask can be used in combination to select one of the sub-tables. An entry in the selected sub-table, corresponding to a transformed version of the input data, can then be identified.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.