diff options
Diffstat (limited to 'src/ltc/pk/ecc/ecc_import.c')
| -rw-r--r-- | src/ltc/pk/ecc/ecc_import.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/src/ltc/pk/ecc/ecc_import.c b/src/ltc/pk/ecc/ecc_import.c new file mode 100644 index 00000000..95cb7e28 --- /dev/null +++ b/src/ltc/pk/ecc/ecc_import.c @@ -0,0 +1,126 @@ +/* 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://libtom.org + */ + +/* Implements ECC over Z/pZ for curve y^2 = x^3 + a*x + b + * + */ +#include "tomcrypt.h" + +/** + @file ecc_import.c + ECC Crypto, Tom St Denis +*/ + +#ifdef LTC_MECC + +/** + Import an ECC key from a binary packet + @param in The packet to import + @param inlen The length of the packet + @param key [out] The destination of the import + @return CRYPT_OK if successful, upon error all allocated memory will be freed +*/ +int ecc_import(const unsigned char *in, unsigned long inlen, ecc_key *key) +{ + return ecc_import_ex(in, inlen, key, NULL); +} + +/** + Import an ECC key from a binary packet, using user supplied domain params rather than one of the NIST ones + @param in The packet to import + @param inlen The length of the packet + @param key [out] The destination of the import + @param dp pointer to user supplied params; must be the same as the params used when exporting + @return CRYPT_OK if successful, upon error all allocated memory will be freed +*/ +int ecc_import_ex(const unsigned char *in, unsigned long inlen, ecc_key *key, const ltc_ecc_set_type *dp) +{ + unsigned long key_size; + unsigned char flags[1]; + int err; + + LTC_ARGCHK(in != NULL); + LTC_ARGCHK(key != NULL); + LTC_ARGCHK(ltc_mp.name != NULL); + + /* init key */ + if (mp_init_multi(&key->pubkey.x, &key->pubkey.y, &key->pubkey.z, &key->k, NULL) != CRYPT_OK) { + return CRYPT_MEM; + } + + /* find out what type of key it is */ + if ((err = der_decode_sequence_multi(in, inlen, + LTC_ASN1_BIT_STRING, 1UL, &flags, + LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) { + goto done; + } + + + if (flags[0] == 1) { + /* private key */ + key->type = PK_PRIVATE; + if ((err = der_decode_sequence_multi(in, inlen, + LTC_ASN1_BIT_STRING, 1UL, flags, + LTC_ASN1_SHORT_INTEGER, 1UL, &key_size, + LTC_ASN1_INTEGER, 1UL, key->pubkey.x, + LTC_ASN1_INTEGER, 1UL, key->pubkey.y, + LTC_ASN1_INTEGER, 1UL, key->k, + LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) { + goto done; + } + } else { + /* public key */ + key->type = PK_PUBLIC; + if ((err = der_decode_sequence_multi(in, inlen, + LTC_ASN1_BIT_STRING, 1UL, flags, + LTC_ASN1_SHORT_INTEGER, 1UL, &key_size, + LTC_ASN1_INTEGER, 1UL, key->pubkey.x, + LTC_ASN1_INTEGER, 1UL, key->pubkey.y, + LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) { + goto done; + } + } + + if (dp == NULL) { + /* BEWARE: Here we are looking up the curve params by keysize (neither curve name nor curve oid), + * which might be ambiguous (there can more than one curve for given keysize). + * Thus the chosen curve depends on order of items in ltc_ecc_sets[] - see ecc.c file. + */ + /* find the idx */ + for (key->idx = 0; ltc_ecc_sets[key->idx].size && (unsigned long)ltc_ecc_sets[key->idx].size != key_size; ++key->idx); + if (ltc_ecc_sets[key->idx].size == 0) { + err = CRYPT_INVALID_PACKET; + goto done; + } + key->dp = <c_ecc_sets[key->idx]; + } else { + key->idx = -1; + key->dp = dp; + } + /* set z */ + if ((err = mp_set(key->pubkey.z, 1)) != CRYPT_OK) { goto done; } + + /* is it a point on the curve? */ + if ((err = ltc_ecc_is_point(key->dp, key->pubkey.x, key->pubkey.y)) != CRYPT_OK) { + goto done; + } + + /* we're good */ + return CRYPT_OK; +done: + mp_clear_multi(key->pubkey.x, key->pubkey.y, key->pubkey.z, key->k, NULL); + return err; +} +#endif +/* $Source$ */ +/* $Revision$ */ +/* $Date$ */ + |