![Texas Instruments SimpleLink Ethernet MSP432E401Y Technical Reference Manual Download Page 669](http://html1.mh-extra.com/html/texas-instruments/simplelink-ethernet-msp432e401y/simplelink-ethernet-msp432e401y_technical-reference-manual_1095578669.webp)
Key Register
Ouput Buffer
(cipher text)
AES Core
(encrypt)
128
128
Key in
256
Temporary Buffer
128
Input Buffer
(plain text)
IV Register
IV Register (counter)
96
32
+
data_in
data_out
128
1
0
32
127
128
128
32 31
X
128
Authentication Key
128
Authentication
Result
128
128
AES Functional Description
669
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
Advance Encryption Standard Accelerator (AES)
9.2.3.1.9 GCM Operation
shows one round of a GCM operation for encryption and decryption. A 32-bit counter is used
as IV (as it is for CTR mode). The data is encrypted in the same way as in CTR mode, by XORing the
cryptographic core output with the input. After the encryption or decryption, the ciphertext is XORed with
the intermediate authentication result. The XORed result is used as input for the polynomial multiplication
to create the next (intermediate) authentication result. For more information about the GCM protocol, see
Figure 9-10. AES – GCM Operation