Mercurial > dropbear
diff src/pk/asn1/der/short_integer/der_decode_short_integer.c @ 280:59400faa4b44 libtomcrypt-orig libtomcrypt-1.05
Re-import libtomcrypt 1.05 for cleaner propagating.
From crypt-1.05.tar.bz2, SHA1 of 88250202bb51570dc64f7e8f1c943cda9479258f
author | Matt Johnston <matt@ucc.asn.au> |
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date | Wed, 08 Mar 2006 12:58:00 +0000 |
parents | |
children | d5faf4814ddb |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/pk/asn1/der/short_integer/der_decode_short_integer.c Wed Mar 08 12:58:00 2006 +0000 @@ -0,0 +1,68 @@ +/* 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.org + */ +#include "tomcrypt.h" + +/** + @file der_decode_short_integer.c + ASN.1 DER, decode an integer, Tom St Denis +*/ + + +#ifdef LTC_DER + +/** + Read a mp_int integer + @param in The DER encoded data + @param inlen Size of data + @param num [out] The integer to decode + @return CRYPT_OK if successful +*/ +int der_decode_short_integer(const unsigned char *in, unsigned long inlen, unsigned long *num) +{ + unsigned long len, x, y; + + LTC_ARGCHK(num != NULL); + LTC_ARGCHK(in != NULL); + + /* check length */ + if (inlen < 2) { + return CRYPT_INVALID_PACKET; + } + + /* check header */ + x = 0; + if ((in[x++] & 0x1F) != 0x02) { + return CRYPT_INVALID_PACKET; + } + + /* get the packet len */ + len = in[x++]; + + if (x + len > inlen) { + return CRYPT_INVALID_PACKET; + } + + /* read number */ + y = 0; + while (len--) { + y = (y<<8) | (unsigned long)in[x++]; + } + *num = y; + + return CRYPT_OK; + +} + +#endif + +/* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/short_integer/der_decode_short_integer.c,v $ */ +/* $Revision: 1.4 $ */ +/* $Date: 2005/05/23 01:04:13 $ */