Datasheet

Register 24: AES Authentication Data Length (AES_AUTH_LENGTH), offset
0x05C
The AES Authentication Data Length (AES_AUTH_LENGTH) register stores the authentication
data length in bytes for combined modes only (GCM or CCM). Supported AUTH lengths for CCM
are from 0 to (2
16
- 28) bytes. For GCM any value up to (2
32
- 1) bytes can be used. Once processing
with this context is started, this length decrements to zero. A write to this register triggers the engine
to start using this context for GCM and CCM. For XTS, this register is optionally used to load j.
Loading of j is only required if j ≠ 0. j is a 28-bit value and must be written to bits [31-4] of this register.
j represents the sequential number of the 128-bit block inside the data unit. For the first block in a
unit, this value is zero. It is not required to provide a j for each new data block within a unit. Note
that it is possible to start with a j unequal to zero.
Note: For a Host read operation, these registers return all-zeroes..
AES Authentication Data Length (AES_AUTH_LENGTH)
Base 0x4403.6000
Offset 0x05C
Type RW, reset 0x0000.0000
16171819202122232425262728293031
AUTH
RWRWRWRWRWRWRWRWRWRWRWRWRWRWRWRWType
0000000000000000Reset
0123456789101112131415
AUTH
RWRWRWRWRWRWRWRWRWRWRWRWRWRWRWRWType
0000000000000000Reset
DescriptionResetTypeNameBit/Field
Authentication Data Length
This field stores the authentication data length in bytes for combined
modes (GCM or CCM).
0x00000000RWAUTH31:0
1019December 13, 2013
Texas Instruments-Advance Information
Tiva
™
TM4C129XNCZAD Microcontroller