view libtomcrypt/notes/tech0005.txt @ 1071:696205e3dc99 pam

Remove ATTRIB_NORETURN from session_loop() since it returns. The stack breaks pretty badly.
author Matt Johnston <matt@ucc.asn.au>
date Tue, 17 Mar 2015 21:58:32 +0800
parents 0cbe8f6dbf9e
children f849a5ca2efc
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Tech Note 0005
Minimizing Code Space
Tom St Denis

Introduction
------------

Tweaking...

You can disable whole classes of algorithms on the command line with the LTC_NO_* defines.  From there you can manually turn on what you want to enable.  

The following build with GCC 3.4.4 on an AMD64 box gets you AES, CTR mode, SHA-256, HMAC, Yarrow, full RSA PKCS #1, PKCS #5 and ASN.1 DER in 
roughly 40KB of code (49KB on the ARMv4) (both excluding the math library).

CFLAGS="-DLTC_NO_CIPHERS -DLTC_NO_HASHES -DLTC_NO_PRNGS -DLTC_NO_MACS -DLTC_NO_MODES -DLTC_NO_PK -DRIJNDAEL -DLTC_CTR_MODE -DSHA256 \
-DLTC_HMAC -DYARROW -DMRSA -DMPI -DTFM_DESC -DARGTYPE=3 -Os -DLTC_SMALL_CODE -fomit-frame-pointer" make IGNORE_SPEED=1

Obviously this won't get you performance but if you need to pack a crypto lib in a device with limited means it's more than enough...

Neato eh?