Mercurial > dropbear
view libtomcrypt/src/pk/asn1/der/bit/der_encode_bit_string.c @ 397:2908122e9eed channel-fix
disapproval of revision '1250b8af44b62d8f4fe0f8d9fc7e7a1cc34e7e1c'
author | Matt Johnston <matt@ucc.asn.au> |
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date | Sat, 03 Feb 2007 08:10:09 +0000 |
parents | 1b9e69c058d2 |
children | 0cbe8f6dbf9e |
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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.org */ #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, 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) { 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++] = y; } else if (y < 256) { out[x++] = 0x81; out[x++] = y; } else if (y < 65536) { out[x++] = 0x82; out[x++] = (y>>8)&255; out[x++] = y&255; } /* store number of zero padding bits */ out[x++] = (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: 1.1 $ */ /* $Date: 2005/05/16 15:08:11 $ */