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I want to implement AES-128 CFB (Chiper Feedback) algorithm using HW Cryptographic processor on STM32F437 microcontroller.

I don't want to use "STM32 crypto library" (DocID028112 Rev 2), but I want to write my custom library from scratch.

The problem is: On STM32F437 reference manual (DocID018909 Rev 14) at page 721 is written that the only AES algorithms implemented are ECB, CBC, CTR, CCM and GCM:

Pag. 721/1745 DocID018909 Rev 14

But on "STM32 crypto library" user manual (DocID028112 Rev 2) is written that CFB algorithm is supported on STM32F437:

Pag. 25/184 DocID028112 Rev 2

In STM32F437 reference manual there is no procedure to implement AES CFB algorithm and inside ST HAL driver there aren't function for AES CFB.

What's wrong? How can I implement AES 128 CFB algorithm on STM32F437?

Many thanks!

leoc7
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    The library might support it using ECB primitive and implementing the chaining in SW.. Generally, it's a bad idea to implement you crypto from scratch (not sure how secure ST library though, given the ridiculous bugs I've encountered before..). – Eugene Sh. Jun 12 '17 at 14:22
  • @EugeneSh. Thanks for suggestion! I can't use "STM32 crypto library" on my compiler (mikroC pro for ARM) because it doesn't support ".a" static library. So, I have to implement AES CFB from scratch. – leoc7 Jun 12 '17 at 14:44
  • I am pretty sure the library is provided as source code too. – Eugene Sh. Jun 12 '17 at 14:53
  • @EugeneSh. No, I can't find source code. Could you help me? Thanks! – leoc7 Jun 12 '17 at 15:34
  • Yeah.. at leas from the doc referenced it's binary distribution only – Eugene Sh. Jun 12 '17 at 15:42
  • @EugeneSh. So, I have to implement AES CFB from scratch using ECB... – leoc7 Jun 12 '17 at 15:55

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