Si102x/3x
14.6.5.1. CTR Data Flow
The AES0 module data flow for CTR encryption and decryption shown in Figure 14.5. The data flow is the
same for encryption and decryption. AES0DCFG is always configured to XOR AES0XIN with the AES core
output.The XOR on the input is not used. The AES core is configured for an encryption operation. The
encryption key is written to AES0KIN. The key size is set to the desired key size.
For an encryption operation, the plaintext is written to AES0BIN and the ciphertext is read from
AES0YOUT. For decryption, the ciphertext is written to AES0BIN and the plaintext is read from
AES0YOUT.
Note the counter must be incremented after each block using software.
AES0BIN
internal state
machine
AES0XIN
+
AES0DCFG
Data In
AES
Core
Key
In
Key
Out
AES0KIN
Data Out
AES0BCFG
+
AES0YOUT
Figure 14.8. Counter Mode Data Flow
200
Rev. 0.3
SILICON [ SILICON ]
