AES Data Tables
3 AES Data Tables
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.1 Introduction
The Advanced Encryption Standard (AES) is a publicly defined encryption standard used by the
U.S. Government. It is a strong encryption method with reasonable performance and size. AES
is fast in both hardware and software, is fairly easy to implement, and requires little memory. AES
is ideal for applications that can use pre-arranged keys, such as setup during manufacturing or
configuration.
Four data tables used by the XySSL AES implementation are provided in the ROM. The first is
the forward S-box substitution table, the second is the reverse S-box substitution table, the third is
the forward polynomial table, and the final is the reverse polynomial table. The meanings of these
tables and their use can be found in the AES code provided in TivaWare.
3.2 Data Structures
Data Structures
ROM_pvAESTable
3.2.1 Data Structure Documentation
3.2.1.1 ROM_pvAESTable
This structure describes the AES tables that are available in the ROM.
ROM Location:
ROM_APITABLE is an array of pointers located at 0x0100.0010.
ROM_SOFTWARETABLE is an array of pointers located at ROM_APITABLE[21].
ROM_pvAESTable is an array located at &ROM_SOFTWARETABLE[7].
Definition:
typedef struct
{
unsigned char ucForwardSBox[256];
unsigned long ulForwardTable[256];
unsigned char ucReverseSBox[256];
unsigned long ulReverseTable[256];
}
ROM_pvAESTable
Members:
ucForwardSBox This table contains the forward S-Box, as defined by the AES standard.
April 8, 2013 27
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