diff options
Diffstat (limited to 'libtomcrypt/src/pk/ecc/ecc_ansi_x963_export.c')
| -rw-r--r-- | libtomcrypt/src/pk/ecc/ecc_ansi_x963_export.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/libtomcrypt/src/pk/ecc/ecc_ansi_x963_export.c b/libtomcrypt/src/pk/ecc/ecc_ansi_x963_export.c new file mode 100644 index 0000000..2a32912 --- /dev/null +++ b/libtomcrypt/src/pk/ecc/ecc_ansi_x963_export.c @@ -0,0 +1,72 @@ +/* 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.com + */ + +/* Implements ECC over Z/pZ for curve y^2 = x^3 - 3x + b + * + * All curves taken from NIST recommendation paper of July 1999 + * Available at http://csrc.nist.gov/cryptval/dss.htm + */ +#include "tomcrypt.h" + +/** + @file ecc_ansi_x963_export.c + ECC Crypto, Tom St Denis +*/ + +#ifdef MECC + +/** ECC X9.63 (Sec. 4.3.6) uncompressed export + @param key Key to export + @param out [out] destination of export + @param outlen [in/out] Length of destination and final output size + Return CRYPT_OK on success +*/ +int ecc_ansi_x963_export(ecc_key *key, unsigned char *out, unsigned long *outlen) +{ + unsigned char buf[ECC_BUF_SIZE]; + unsigned long numlen; + + LTC_ARGCHK(key != NULL); + LTC_ARGCHK(out != NULL); + LTC_ARGCHK(outlen != NULL); + + if (ltc_ecc_is_valid_idx(key->idx) == 0) { + return CRYPT_INVALID_ARG; + } + numlen = key->dp->size; + + if (*outlen < (1 + 2*numlen)) { + *outlen = 1 + 2*numlen; + return CRYPT_BUFFER_OVERFLOW; + } + + /* store byte 0x04 */ + out[0] = 0x04; + + /* pad and store x */ + zeromem(buf, sizeof(buf)); + mp_to_unsigned_bin(key->pubkey.x, buf + (numlen - mp_unsigned_bin_size(key->pubkey.x))); + XMEMCPY(out+1, buf, numlen); + + /* pad and store y */ + zeromem(buf, sizeof(buf)); + mp_to_unsigned_bin(key->pubkey.y, buf + (numlen - mp_unsigned_bin_size(key->pubkey.y))); + XMEMCPY(out+1+numlen, buf, numlen); + + *outlen = 1 + 2*numlen; + return CRYPT_OK; +} + +#endif + +/* $Source: /cvs/libtom/libtomcrypt/src/pk/ecc/ecc_ansi_x963_export.c,v $ */ +/* $Revision: 1.4 $ */ +/* $Date: 2006/12/04 02:50:11 $ */ |