diff options
Diffstat (limited to 'libtomcrypt/src/pk/asn1/der/bit')
3 files changed, 242 insertions, 0 deletions
diff --git a/libtomcrypt/src/pk/asn1/der/bit/der_decode_bit_string.c b/libtomcrypt/src/pk/asn1/der/bit/der_decode_bit_string.c new file mode 100644 index 0000000..da5b989 --- /dev/null +++ b/libtomcrypt/src/pk/asn1/der/bit/der_decode_bit_string.c @@ -0,0 +1,101 @@ +/* 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, tomstdenis@gmail.com, http://libtomcrypt.org + */ +#include "tomcrypt.h" + +/** + @file der_decode_bit_string.c + ASN.1 DER, encode a BIT STRING, Tom St Denis +*/ + + +#ifdef LTC_DER + +/** + Store a BIT STRING + @param in The DER encoded BIT STRING + @param inlen The size of the DER BIT STRING + @param out [out] The array of bits stored (one per char) + @param outlen [in/out] The number of bits stored + @return CRYPT_OK if successful +*/ +int der_decode_bit_string(const unsigned char *in, unsigned long inlen, + unsigned char *out, unsigned long *outlen) +{ + unsigned long dlen, blen, x, y; + + LTC_ARGCHK(in != NULL); + LTC_ARGCHK(out != NULL); + LTC_ARGCHK(outlen != NULL); + + /* packet must be at least 4 bytes */ + if (inlen < 4) { + return CRYPT_INVALID_ARG; + } + + /* check for 0x03 */ + if ((in[0]&0x1F) != 0x03) { + return CRYPT_INVALID_PACKET; + } + + /* offset in the data */ + x = 1; + + /* get the length of the data */ + if (in[x] & 0x80) { + /* long format get number of length bytes */ + y = in[x++] & 127; + + /* invalid if 0 or > 2 */ + if (y == 0 || y > 2) { + return CRYPT_INVALID_PACKET; + } + + /* read the data len */ + dlen = 0; + while (y--) { + dlen = (dlen << 8) | (unsigned long)in[x++]; + } + } else { + /* short format */ + dlen = in[x++] & 127; + } + + /* is the data len too long or too short? */ + if ((dlen == 0) || (dlen + x > inlen)) { + return CRYPT_INVALID_PACKET; + } + + /* get padding count */ + blen = ((dlen - 1) << 3) - (in[x++] & 7); + + /* too many bits? */ + if (blen > *outlen) { + return CRYPT_BUFFER_OVERFLOW; + } + + /* decode/store the bits */ + for (y = 0; y < blen; y++) { + out[y] = (in[x] & (1 << (7 - (y & 7)))) ? 1 : 0; + if ((y & 7) == 7) { + ++x; + } + } + + /* we done */ + *outlen = blen; + return CRYPT_OK; +} + +#endif + +/* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/bit/der_decode_bit_string.c,v $ */ +/* $Revision: 1.1 $ */ +/* $Date: 2005/05/16 15:08:11 $ */ diff --git a/libtomcrypt/src/pk/asn1/der/bit/der_encode_bit_string.c b/libtomcrypt/src/pk/asn1/der/bit/der_encode_bit_string.c new file mode 100644 index 0000000..569c15b --- /dev/null +++ b/libtomcrypt/src/pk/asn1/der/bit/der_encode_bit_string.c @@ -0,0 +1,87 @@ +/* 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, tomstdenis@gmail.com, 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 $ */ diff --git a/libtomcrypt/src/pk/asn1/der/bit/der_length_bit_string.c b/libtomcrypt/src/pk/asn1/der/bit/der_length_bit_string.c new file mode 100644 index 0000000..dd6ea6d --- /dev/null +++ b/libtomcrypt/src/pk/asn1/der/bit/der_length_bit_string.c @@ -0,0 +1,54 @@ +/* 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, tomstdenis@gmail.com, http://libtomcrypt.org + */ +#include "tomcrypt.h" + +/** + @file der_length_bit_string.c + ASN.1 DER, get length of BIT STRING, Tom St Denis +*/ + +#ifdef LTC_DER +/** + Gets length of DER encoding of BIT STRING + @param nbits The number of bits in the string to encode + @param outlen [out] The length of the DER encoding for the given string + @return CRYPT_OK if successful +*/ +int der_length_bit_string(unsigned long nbits, unsigned long *outlen) +{ + unsigned long nbytes; + LTC_ARGCHK(outlen != NULL); + + /* get the number of the bytes */ + nbytes = (nbits >> 3) + ((nbits & 7) ? 1 : 0) + 1; + + if (nbytes < 128) { + /* 03 LL PP DD DD DD ... */ + *outlen = 2 + nbytes; + } else if (nbytes < 256) { + /* 03 81 LL PP DD DD DD ... */ + *outlen = 3 + nbytes; + } else if (nbytes < 65536) { + /* 03 82 LL LL PP DD DD DD ... */ + *outlen = 4 + nbytes; + } else { + return CRYPT_INVALID_ARG; + } + + return CRYPT_OK; +} + +#endif + + +/* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/bit/der_length_bit_string.c,v $ */ +/* $Revision: 1.1 $ */ +/* $Date: 2005/05/16 15:08:11 $ */ |