Encryption Library Hardware Acceleration: Kinetis CAU
The Kinetis Cryptographic Acceleration Unit (CAU) is a primitive accelerator presented as a memory-mapped peripheral.
The SEGGER encryption library has specialized hardware-assisted ciphering and hashing support
The following cryptographic algorithms using the CAU:
- DES in ECB and CBC modes.
- TDES in ECB and CBC modes with keying options 1, 2, and 3.
- AES-128, AES-192, and AES-256 in ECB and CBC modes.
- MD5
- SHA-1
- SHA-256
- RNG
All other cipher modes (e.g. AES-GCM and AES-CCM) use hardware-assisted ciphering of individual blocks with software taking care of the cipher mode.
| Cipher | Mode | Software Performance | Hardware Performance | Speedup | |
|---|---|---|---|---|---|
| AES-128-ECB | Encrypt | 2.17 MB/s | 8.20 MB/s | x3.8 | |
| AES-192-ECB | Encrypt | 1.86 MB/s | 6.87 MB/s | x3.7 | |
| AES-256-ECB | Encrypt | 1.62 MB/s | 6.09 MB/s | x3.8 | |
| AES-128-CBC | Encrypt | 1.72 MB/s | 7.91 MB/s | x4.6 | |
| AES-192-CBC | Encrypt | 1.52 MB/s | 6.56 MB/s | x4.3 | |
| AES-256-CBC | Encrypt | 1.36 MB/s | 5.85 MB/s | x4.3 | |
| AES-128-CBC | Decrypt | 1.61 MB/s | 6.67 MB/s | x4.2 | |
| AES-192-CBC | Decrypt | 1.43 MB/s | 5.77 MB/s | x4.0 | |
| AES-256-CBC | Decrypt | 1.29 MB/s | 5.08 MB/s | x3.9 | |
| Cipher | Mode | Software Performance | Hardware Performance | Speedup | |
|---|---|---|---|---|---|
| DES-ECB | Encrypt | 1.05 MB/s | 11.74 MB/s | x11.2 | |
| DES-EDE2-ECB | Encrypt | 0.36 MB/s | 11.74 MB/s | x32.6 | |
| DES-EDE3-ECB | Encrypt | 0.36 MB/s | 11.74 MB/s | x32.6 | |
| DES-CBC | Encrypt | 0.90 MB/s | 11.84 MB/s | x13.1 | |
| DES-EDE2-CBC | Encrypt | 0.34 MB/s | 11.85 MB/s | x34.7 | |
| DES-EDE3-CBC | Encrypt | 0.34 MB/s | 11.85 MB/s | x34.7 | |
| DES-CBC | Decrypt | 0.84 MB/s | 9.48 MB/s | x11.3 | |
| DES-EDE2-CBC | Decrypt | 0.33 MB/s | 9.48 MB/s | x28.7 | |
| DES-EDE3-CBC | Decrypt | 0.33 MB/s | 9.48 MB/s | x28.7 | |