Si102x/3x
14.5.2. AES Block Cipher Decryption using SFRs
First, configure AES module for AES Block Cipher
AES module by writing 0x00 to AES0BCFG.
Configure the AES Module data flow for AES Block Cipher by writing 0x00 to AES0DCFG.
Write key size to bits 1 and 0 of AES0BCFG.
Configure the AES core for decryption by setting bit 2 of AES0BCFG.
Enable the AES core by setting bit 3 of AES0BCFG.
Reset
Repeat alternating write sequence 16 times
ciphertext byte to AES0BIN.
Write decryption key byte to AES0KIN.
Write
Write remaining decryption key bytes to AES0KIN for 192-bit and 256-bit decryption only.
Wait on AES done interrupt or poll bit 5 of AES0BCFG.
Read 16 plaintext bytes from AES0YOUT.
If decrypting multiple blocks, this process may be repeated. It is not necessary reconfigure the AES mod-
ule for each block.
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