/* 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.
*/
/* Implements ECC over Z/pZ for curve y^2 = x^3 + a*x + b
*
*/
#include "tomcrypt.h"
#ifdef LTC_MECC
int ecc_import_full(const unsigned char *in, unsigned long inlen, ecc_key *key, ltc_ecc_set_type *dp)
{
void *prime, *order, *a, *b, *gx, *gy;
ltc_asn1_list seq_fieldid[2], seq_curve[3], seq_ecparams[6], seq_priv[4];
unsigned char bin_a[ECC_MAXSIZE], bin_b[ECC_MAXSIZE], bin_k[ECC_MAXSIZE], bin_g[2*ECC_MAXSIZE+1], bin_xy[2*ECC_MAXSIZE+2], bin_seed[128];
unsigned long len_a, len_b, len_k, len_g, len_xy, len_oid;
unsigned long cofactor = 0, ecver = 0, pkver = 0, tmpoid[16], curveoid[16];
int err;
if ((err = mp_init_multi(&prime, &order, &a, &b, &gx, &gy, NULL)) != CRYPT_OK) return err;
/* ### 1. try to load public key - no curve parameters just curve OID */
len_xy = sizeof(bin_xy);
err = der_decode_subject_public_key_info_ex(in, inlen, PKA_EC, bin_xy, &len_xy, LTC_ASN1_OBJECT_IDENTIFIER, curveoid, 16UL, &len_oid);
if (err == CRYPT_OK) {
/* load curve parameters for given curve OID */
if ((err = ecc_dp_set_by_oid(dp, curveoid, len_oid)) != CRYPT_OK) { goto error; }
/* load public key */
if ((err = ecc_import_raw(bin_xy, len_xy, key, dp)) != CRYPT_OK) { goto error; }
goto success;
}
/* ### 2. try to load public key - curve parameters included */
/* ECParameters SEQUENCE */
LTC_SET_ASN1(seq_ecparams, 0, LTC_ASN1_SHORT_INTEGER, &ecver, 1UL);
LTC_SET_ASN1(seq_ecparams, 1, LTC_ASN1_SEQUENCE, seq_fieldid, 2UL);
LTC_SET_ASN1(seq_ecparams, 2, LTC_ASN1_SEQUENCE, seq_curve, 3UL);
LTC_SET_ASN1(seq_ecparams, 3, LTC_ASN1_OCTET_STRING, bin_g, (unsigned long)2*ECC_MAXSIZE+1);
LTC_SET_ASN1(seq_ecparams, 4, LTC_ASN1_INTEGER, order, 1UL);
LTC_SET_ASN1(seq_ecparams, 5, LTC_ASN1_SHORT_INTEGER, &cofactor, 1UL);
seq_ecparams[5].optional = 1;
/* FieldID SEQUENCE */
LTC_SET_ASN1(seq_fieldid, 0, LTC_ASN1_OBJECT_IDENTIFIER, tmpoid, 16UL);
LTC_SET_ASN1(seq_fieldid, 1, LTC_ASN1_INTEGER, prime, 1UL);
/* Curve SEQUENCE */
LTC_SET_ASN1(seq_curve, 0, LTC_ASN1_OCTET_STRING, bin_a, (unsigned long)ECC_MAXSIZE);
LTC_SET_ASN1(seq_curve, 1, LTC_ASN1_OCTET_STRING, bin_b, (unsigned long)ECC_MAXSIZE);
LTC_SET_ASN1(seq_curve, 2, LTC_ASN1_RAW_BIT_STRING, bin_seed, (unsigned long)8*128);
seq_curve[2].optional = 1;
/* try to load public key */
len_xy = sizeof(bin_xy);
err = der_decode_subject_public_key_info(in, inlen, PKA_EC, bin_xy, &len_xy, LTC_ASN1_SEQUENCE, seq_ecparams, 6);
if (err == CRYPT_OK) {
len_a = seq_curve[0].size;
len_b = seq_curve[1].size;
len_g = seq_ecparams[3].size;
/* create bignums */
if ((err = mp_read_unsigned_bin(a, bin_a, len_a)) != CRYPT_OK) { goto error; }
if ((err = mp_read_unsigned_bin(b, bin_b, len_b)) != CRYPT_OK) { goto error; }
if ((err = ltc_ecc_import_point(bin_g, len_g, prime, a, b, gx, gy)) != CRYPT_OK) { goto error; }
/* load curve parameters */
if ((err = ecc_dp_set_bn(dp, a, b, prime, order, gx, gy, cofactor)) != CRYPT_OK) { goto error; }
/* load public key */
if ((err = ecc_import_raw(bin_xy, len_xy, key, dp)) != CRYPT_OK) { goto error; }
goto success;
}
/* ### 3. try to load private key - no curve parameters just curve OID */
/* ECPrivateKey SEQUENCE */
LTC_SET_ASN1(seq_priv, 0, LTC_ASN1_SHORT_INTEGER, &pkver, 1UL);
LTC_SET_ASN1(seq_priv, 1, LTC_ASN1_OCTET_STRING, bin_k, (unsigned long)ECC_MAXSIZE);
LTC_SET_ASN1(seq_priv, 2, LTC_ASN1_OBJECT_IDENTIFIER, curveoid, 16UL);
LTC_SET_ASN1(seq_priv, 3, LTC_ASN1_RAW_BIT_STRING, bin_xy, (unsigned long)8*(2*ECC_MAXSIZE+2));
seq_priv[2].tag = 0xA0; /* context specific 0 */
seq_priv[3].tag = 0xA1; /* context specific 1 */
/* try to load private key */
err = der_decode_sequence(in, inlen, seq_priv, 4);
if (err == CRYPT_OK) {
/* load curve parameters for given curve OID */
if ((err = ecc_dp_set_by_oid(dp, curveoid, seq_priv[2].size)) != CRYPT_OK) { goto error; }
/* load private+public key */
if ((err = ecc_import_raw(bin_k, seq_priv[1].size, key, dp)) != CRYPT_OK) { goto error; }
goto success;
}
/* ### 4. try to load private key - curve parameters included */
/* ECPrivateKey SEQUENCE */
LTC_SET_ASN1(seq_priv, 0, LTC_ASN1_SHORT_INTEGER, &pkver, 1UL);
LTC_SET_ASN1(seq_priv, 1, LTC_ASN1_OCTET_STRING, bin_k, (unsigned long)ECC_MAXSIZE);
LTC_SET_ASN1(seq_priv, 2, LTC_ASN1_SEQUENCE, seq_ecparams, 6UL);
LTC_SET_ASN1(seq_priv, 3, LTC_ASN1_RAW_BIT_STRING, bin_xy, (unsigned long)8*(2*ECC_MAXSIZE+2));
seq_priv[2].tag = 0xA0; /* context specific 0 */
seq_priv[3].tag = 0xA1; /* context specific 1 */
/* ECParameters SEQUENCE */
LTC_SET_ASN1(seq_ecparams, 0, LTC_ASN1_SHORT_INTEGER, &ecver, 1UL);
LTC_SET_ASN1(seq_ecparams, 1, LTC_ASN1_SEQUENCE, seq_fieldid, 2UL);
LTC_SET_ASN1(seq_ecparams, 2, LTC_ASN1_SEQUENCE, seq_curve, 3UL);
LTC_SET_ASN1(seq_ecparams, 3, LTC_ASN1_OCTET_STRING, bin_g, (unsigned long)2*ECC_MAXSIZE+1);
LTC_SET_ASN1(seq_ecparams, 4, LTC_ASN1_INTEGER, order, 1UL);
LTC_SET_ASN1(seq_ecparams, 5, LTC_ASN1_SHORT_INTEGER, &cofactor, 1UL);
seq_ecparams[5].optional = 1;
/* FieldID SEQUENCE */
LTC_SET_ASN1(seq_fieldid, 0, LTC_ASN1_OBJECT_IDENTIFIER, tmpoid, 16UL);
LTC_SET_ASN1(seq_fieldid, 1, LTC_ASN1_INTEGER, prime, 1UL);
/* Curve SEQUENCE */
LTC_SET_ASN1(seq_curve, 0, LTC_ASN1_OCTET_STRING, bin_a, (unsigned long)ECC_MAXSIZE);
LTC_SET_ASN1(seq_curve, 1, LTC_ASN1_OCTET_STRING, bin_b, (unsigned long)ECC_MAXSIZE);
LTC_SET_ASN1(seq_curve, 2, LTC_ASN1_RAW_BIT_STRING, bin_seed, (unsigned long)8*128);
seq_curve[2].optional = 1;
/* try to load private key */
err = der_decode_sequence(in, inlen, seq_priv, 4);
if (err == CRYPT_OK) {
len_k = seq_priv[1].size;
len_xy = seq_priv[3].size;
len_a = seq_curve[0].size;
len_b = seq_curve[1].size;
len_g = seq_ecparams[3].size;
/* create bignums */
if ((err = mp_read_unsigned_bin(a, bin_a, len_a)) != CRYPT_OK) { goto error; }
if ((err = mp_read_unsigned_bin(b, bin_b, len_b)) != CRYPT_OK) { goto error; }
if ((err = ltc_ecc_import_point(bin_g, len_g, prime, a, b, gx, gy)) != CRYPT_OK) { goto error; }
/* load curve parameters */
if ((err = ecc_dp_set_bn(dp, a, b, prime, order, gx, gy, cofactor)) != CRYPT_OK) { goto error; }
/* load private+public key */
if ((err = ecc_import_raw(bin_k, len_k, key, dp)) != CRYPT_OK) { goto error; }
goto success;
}
/* ### 5. backward compatibility - try to load old-DER format */
if ((err = ecc_import(in, inlen, key)) != CRYPT_OK) { goto error; }
success:
err = CRYPT_OK;
error:
mp_clear_multi(prime, order, a, b, gx, gy, NULL);
return err;
}
#endif