Texas Instruments SimpleLink CC2620 Technical Reference Manual page 852

Cryptography Registers
10.2.1.21 AESDATALEN1 Register (Offset = 558h) [reset = 0h]
AESDATALEN1 is shown in
Crypto Data Length MSW
31 30 29 28
RESERVED
W-0h
15 14 13 12
Bit Field
31-29 RESERVED
28-0 LEN_MSW
852
Figure 10-23 and described in
Figure 10-23. AESDATALEN1 Register
27 26 25 24
11 10 9 8
LEN_MSW
W-0h
Table 10-31. AESDATALEN1 Register Field Descriptions
Type Reset
W 0h
W 0h
Copyright © 2015, Texas Instruments Incorporated
Table 10-31.
23 22 21 20
LEN_MSW
W-0h
7 6 5 4
Description
Software must not rely on the value of a reserved. Writing any other
value than the reset value may result in undefined behavior.
Bits [60:32] of the combined data length.
Bits [60:0] of the crypto length registers AESDATALEN1 and
AESDATALEN0 store the cryptographic data length in bytes for all
modes. Once processing with this context is started, this length
decrements to zero. Data lengths up to (2
36
For GCM, any value up to 2 – 32 bytes can be used. This is
because a 32-bit counter mode is used
the maximum number of 128-bit blocks is 2
36
maximum number of bytes of 2
Writing to this register triggers the engine to start using this context.
This is valid for all modes except GCM and CCM.
Note: For the combined modes (GCM and CCM), this length does
not include the authentication only data
the authentication length is specified in the AESAUTHLEN.LEN.
All modes must have a length > 0. For the combined modes, it is
allowed to have one of the lengths equal to zero.
For the basic encryption modes (ECB/CBC/CTR) it is allowed to
program zero to the length field
in that case the length is assumed infinite.
All data must be byte (8-bit) aligned for stream cipher modes
bit aligned data streams are not supported by the Crypto peripheral.
For block cipher modes, the data length must be programmed in
multiples of the block cipher size, 16 bytes.
SWCU117C – February 2015 – Revised September 2015
www.ti.com
19 18 17 16
3 2 1
61
– 1) bytes are allowed.
32
– 2, resulting in a
– 32.
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