Mercurial > dropbear
view libtomcrypt/notes/tech0005.txt @ 1663:c795520269f9
Fallback for key gen without hard link support (#89)
Add a non-atomic fallback for key generation on platforms where link()
is not permitted (such as most stock Android installs) or on filesystems
without hard link support (such as FAT).
| author | Matt Robinson <git@nerdoftheherd.com> |
|---|---|
| date | Sat, 14 Mar 2020 14:37:35 +0000 |
| parents | f849a5ca2efc |
| children |
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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 -DLTC_RIJNDAEL -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?