Mercurial > dropbear
view libtomcrypt/src/pk/asn1/der/bit/der_encode_bit_string.c @ 913:6e2aa862e167
The arguments are for configure, not make!
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Fri, 07 Mar 2014 20:52:57 +0800 |
parents | 0cbe8f6dbf9e |
children | f849a5ca2efc |
line wrap: on
line source
/* 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 */ #include "tomcrypt.h" /** @file der_encode_bit_string.c ASN.1 DER, encode a BIT STRING, Tom St Denis */ #ifdef LTC_DER /** Store a BIT STRING @param in The array of bits to store (one per char) @param inlen The number of bits tostore @param out [out] The destination for the DER encoded BIT STRING @param outlen [in/out] The max size and resulting size of the DER BIT STRING @return CRYPT_OK if successful */ int der_encode_bit_string(const unsigned char *in, unsigned long inlen, unsigned char *out, unsigned long *outlen) { unsigned long len, x, y; unsigned char buf; int err; LTC_ARGCHK(in != NULL); LTC_ARGCHK(out != NULL); LTC_ARGCHK(outlen != NULL); /* avoid overflows */ if ((err = der_length_bit_string(inlen, &len)) != CRYPT_OK) { return err; } if (len > *outlen) { *outlen = len; return CRYPT_BUFFER_OVERFLOW; } /* store header (include bit padding count in length) */ x = 0; y = (inlen >> 3) + ((inlen&7) ? 1 : 0) + 1; out[x++] = 0x03; if (y < 128) { out[x++] = (unsigned char)y; } else if (y < 256) { out[x++] = 0x81; out[x++] = (unsigned char)y; } else if (y < 65536) { out[x++] = 0x82; out[x++] = (unsigned char)((y>>8)&255); out[x++] = (unsigned char)(y&255); } /* store number of zero padding bits */ out[x++] = (unsigned char)((8 - inlen) & 7); /* store the bits in big endian format */ for (y = buf = 0; y < inlen; y++) { buf |= (in[y] ? 1 : 0) << (7 - (y & 7)); if ((y & 7) == 7) { out[x++] = buf; buf = 0; } } /* store last byte */ if (inlen & 7) { out[x++] = buf; } *outlen = x; return CRYPT_OK; } #endif /* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/bit/der_encode_bit_string.c,v $ */ /* $Revision: 1.4 $ */ /* $Date: 2006/12/04 21:34:03 $ */