Cryptographic processing using a processor
US8452006B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 8, 2010 |
| Grant date | May 28, 2013 |
| Priority date | — |
| Expiry date | Mar 25, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2209/125
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In one embodiment, a cryptography processor compatible with the Advanced Encryption Standard (AES) for encrypting and decrypting has a memory storing each element of an AES State, normally 8-bit long, in a corresponding memory space that is at least 9 bits long. Using the larger memory spaces, the processor performs modified AES transformations on the State. A modified column-mixing transformation uses bit-shifting and XOR operations, thereby avoiding some multiplications and modulo reductions and resulting in some 9-bit State elements. A modified byte-substitution transformation uses a 512-element look-up table to accommodate 9-bit inputs. The modified byte-substitution transformation is combined with a modified row-shifting transformation. The memory has data registers each holding four State elements. A modified expanded key schedule is used in a modified round-key-adding transformation that is combined with the modified column-mixing transformation, wherein all four elements stored in a single data register are processed together in some operations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.