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Last updated: 27 Aug 2020
The Freedom-K64F is an ultra-low-cost development platform for Kinetis K64, K63, and K24 MCUs.

K64F crypto-acceleration unit (CAU)

Topic last updated 28 Jan 2019, by Liam Cox. 2 replies
tom dunigan
14 Nov 2015

The K64F has a crypto-acceleration unit (CAU) that can speedup software DES/AES/SHA/MD5. Freescale has an assembler wrapper at http://www.freescale.com/products/arm-processors/kinetis-cortex-m/k-series/k7x-glcd-mcus/crypto-acceleration-unit-cau-and-mmcau-software-library:CAUAP The CAU speeds the time-critical crypto operations, and the library only accesses those basic operations, so you still need to add logic for padding hash input and doing CBC encryption. The Freescale library is in GNU C/assembler so it doesn't work with MBED on-line compiler. I exported the GNU GCC MBED build environment to test the CAU library on K64F @ 120MHz. Here are some preliminary results comparing CAU with C implementation:

                 CAU        C
MD5 (KBs)      10964      5471
SHA256(KBs)     3322      2165
AES set key(us)    3        25      128-bit key
AES CBC (us)      11       189       64 bytes

Has anyone ported the CAU library to work with the MBED on-line compiler?

Julian Higginson
14 Jan 2016

oooh! this is something I might like to see working in mbed. have you had a chance to make any progress with this yourself?

Liam Cox
28 Jan 2019

Is there any follow-up to this post? I'm struggling to use the on board encryption.