RM0090: Reference manual - STMicroelectronics

RM0090 Cryptographic processor (CRYP)
20 Cryptographic processor (CRYP)
This section applies to the whole STM32F4xx family, unless otherwise specified.
20.1 CRYP introduction
The cryptographic processor can be used to both encipher and decipher data using the
DES, Triple-DES or AES (128, 192, or 256) algorithms. It is a fully compliant implementation
of the following standards:
● The data encryption standard (DES) and Triple-DES (TDES) as defined by Federal
Information Processing Standards Publication (FIPS PUB 46-3, 1999 October 25). It
follows the American National Standards Institute (ANSI) X9.52 standard.
● The advanced encryption standard (AES) as defined by Federal Information
Processing Standards Publication (FIPS PUB 197, 2001 November 26)
The CRYP processor performs data encryption and decryption using DES and TDES
algorithms in Electronic codebook (ECB) or Cipher block chaining (CBC) mode.
The CRYP peripheral is a 32-bit AHB2 peripheral. It supports DMA transfer for incoming and
processed data, and has input and output FIFOs (each 8 words deep).
20.2 CRYP main features
● Suitable for AES, DES and TDES enciphering and deciphering operations
● AES
– Supports the ECB, CBC, CTR, CCM and GCM chaining algorithms (CCM and
GCM are available on STM32F42x and STM32F43x only)
– Supports 128-, 192- and 256-bit keys
– 4 × 32-bit initialization vectors (IV) used in the CBC, CTR, CCM and GCM modes
Table 87. Number of cycles required to process each 128-bit block (STM32F40x and STM32F41x)
Algorithm / Key size ECB CBC CTR
128b 14 14 14
192b 16 16 16
256b 18 18 18
Table 88. Number of cycles required to process each 128-bit block (STM32F42x and STM32F43x)
Algorithm /
Key size
ECB CBC CTR
GCM CCM
Init Header Payload Tag Init Header Payload Tag
128b 14 14 14 24 10 14 14 12 14 25 14
192b 16 16 16 28 10 16 16 14 16 29 16
256b 18 18 18 32 10 18 18 16 18 33 18
Doc ID 018909 Rev 3 544/1416