| Tech Note 0005 |
| Minimizing Code Space |
| Tom St Denis |
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| Introduction |
| ------------ |
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| Tweaking... |
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| 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. |
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| 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). |
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| 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 |
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| 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... |
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| Neato eh? |
