Counter Mode (Ctr) - ST STM32F413 Reference Manual

Advanced encryption standard hardware accelerator (AES)
24.5.3

Counter Mode (CTR)

In counter mode, a 32-bit counter is used in addition to a nonce value for the XOR operation
with the cipher text or plain text (refer to
688/1284
Figure 230
Figure 230. CTR mode encryption
Figure 231. CTR mode decryption
DocID029473 Rev 3
and Figure 231).
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