Mercurial > dropbear
view libtomcrypt/src/encauth/ocb/ocb_ntz.c @ 994:5c5ade336926
Prefer stronger algorithms in algorithm negotiation.
Prefer diffie-hellman-group14-sha1 (2048 bit) over
diffie-hellman-group1-sha1 (1024 bit).
Due to meet-in-the-middle attacks the effective key length of
three key 3DES is 112 bits. AES is stronger and faster then 3DES.
Prefer to delay the start of compression until after authentication
has completed. This avoids exposing compression code to attacks
from unauthenticated users.
(github pull request #9)
| author | Fedor Brunner <fedor.brunner@azet.sk> |
|---|---|
| date | Fri, 23 Jan 2015 23:00:25 +0800 |
| parents | 0cbe8f6dbf9e |
| children | f849a5ca2efc |
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/* LibTomCrypt, modular cryptographic library -- Tom St Denis * * LibTomCrypt is a library that provides various cryptographic * algorithms in a highly modular and flexible manner. * * The library is free for all purposes without any express * guarantee it works. * * Tom St Denis, [email protected], http://libtomcrypt.com */ /** @file ocb_ntz.c OCB implementation, internal function, by Tom St Denis */ #include "tomcrypt.h" #ifdef OCB_MODE /** Returns the number of leading zero bits [from lsb up] @param x The 32-bit value to observe @return The number of bits [from the lsb up] that are zero */ int ocb_ntz(unsigned long x) { int c; x &= 0xFFFFFFFFUL; c = 0; while ((x & 1) == 0) { ++c; x >>= 1; } return c; } #endif /* $Source: /cvs/libtom/libtomcrypt/src/encauth/ocb/ocb_ntz.c,v $ */ /* $Revision: 1.4 $ */ /* $Date: 2006/03/31 14:15:35 $ */