| // SPDX-License-Identifier: BSD-2-Clause |
| /* 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. |
| */ |
| |
| #include "tomcrypt_private.h" |
| |
| #ifdef LTC_MECC |
| |
| /** |
| Export an ECC key as a binary packet |
| @param out [out] Destination for the key |
| @param outlen [in/out] Max size and resulting size of the exported key |
| @param type The type of key you want to export (PK_PRIVATE or PK_PUBLIC) |
| @param key The key to export |
| @return CRYPT_OK if successful |
| */ |
| |
| int ecc_export_openssl(unsigned char *out, unsigned long *outlen, int type, const ecc_key *key) |
| { |
| int err; |
| void *prime, *order, *a, *b, *gx, *gy; |
| unsigned char bin_a[256], bin_b[256], bin_k[256], bin_g[512], bin_xy[512]; |
| unsigned long len_a, len_b, len_k, len_g, len_xy; |
| unsigned long cofactor, one = 1; |
| const char *OID; |
| unsigned long oid[16], oidlen; |
| ltc_asn1_list seq_fieldid[2], seq_curve[2], seq_ecparams[6], seq_priv[4], pub_xy, ecparams; |
| int flag_oid = type & PK_CURVEOID ? 1 : 0; |
| int flag_com = type & PK_COMPRESSED ? 1 : 0; |
| int flag_pri = type & PK_PRIVATE ? 1 : 0; |
| |
| LTC_ARGCHK(out != NULL); |
| LTC_ARGCHK(outlen != NULL); |
| LTC_ARGCHK(key != NULL); |
| |
| if (key->type != PK_PRIVATE && flag_pri) return CRYPT_PK_TYPE_MISMATCH; |
| |
| prime = key->dp.prime; |
| order = key->dp.order; |
| b = key->dp.B; |
| a = key->dp.A; |
| gx = key->dp.base.x; |
| gy = key->dp.base.y; |
| |
| /* curve param a */ |
| len_a = mp_unsigned_bin_size(a); |
| if (len_a > sizeof(bin_a)) { err = CRYPT_BUFFER_OVERFLOW; goto error; } |
| if ((err = mp_to_unsigned_bin(a, bin_a)) != CRYPT_OK) { goto error; } |
| if (len_a == 0) { len_a = 1; bin_a[0] = 0; } /* handle case a == 0 */ |
| |
| /* curve param b */ |
| len_b = mp_unsigned_bin_size(b); |
| if (len_b > sizeof(bin_b)) { err = CRYPT_BUFFER_OVERFLOW; goto error; } |
| if ((err = mp_to_unsigned_bin(b, bin_b)) != CRYPT_OK) { goto error; } |
| if (len_b == 0) { len_b = 1; bin_b[0] = 0; } /* handle case b == 0 */ |
| |
| /* base point - (un)compressed based on flag_com */ |
| len_g = sizeof(bin_g); |
| err = ltc_ecc_export_point(bin_g, &len_g, gx, gy, key->dp.size, flag_com); |
| if (err != CRYPT_OK) { goto error; } |
| |
| /* public key - (un)compressed based on flag_com */ |
| len_xy = sizeof(bin_xy); |
| err = ltc_ecc_export_point(bin_xy, &len_xy, key->pubkey.x, key->pubkey.y, key->dp.size, flag_com); |
| if (err != CRYPT_OK) { goto error; } |
| |
| /* co-factor */ |
| cofactor = key->dp.cofactor; |
| |
| /* we support only prime-field EC */ |
| if ((err = pk_get_oid(PKA_EC_PRIMEF, &OID)) != CRYPT_OK) { goto error; } |
| |
| if (flag_oid) { |
| /* http://tools.ietf.org/html/rfc5912 |
| ECParameters ::= CHOICE { |
| namedCurve CURVE.&id({NamedCurve}) # OBJECT |
| } |
| */ |
| if (key->dp.oidlen == 0) { err = CRYPT_INVALID_ARG; goto error; } |
| LTC_SET_ASN1(&ecparams, 0, LTC_ASN1_OBJECT_IDENTIFIER, key->dp.oid, key->dp.oidlen); |
| } |
| else { |
| /* http://tools.ietf.org/html/rfc3279 |
| ECParameters ::= SEQUENCE { # SEQUENCE |
| version INTEGER { ecpVer1(1) } (ecpVer1) # INTEGER :01 |
| FieldID ::= SEQUENCE { # SEQUENCE |
| fieldType FIELD-ID.&id({IOSet}), # OBJECT :prime-field |
| parameters FIELD-ID.&Type({IOSet}{@fieldType}) # INTEGER |
| } |
| Curve ::= SEQUENCE { # SEQUENCE |
| a FieldElement ::= OCTET STRING # OCTET STRING |
| b FieldElement ::= OCTET STRING # OCTET STRING |
| seed BIT STRING OPTIONAL |
| } |
| base ECPoint ::= OCTET STRING # OCTET STRING |
| order INTEGER, # INTEGER |
| cofactor INTEGER OPTIONAL # INTEGER |
| } |
| */ |
| |
| oidlen = sizeof(oid)/sizeof(oid[0]); |
| if ((err = pk_oid_str_to_num(OID, oid, &oidlen)) != CRYPT_OK) { |
| goto error; |
| } |
| |
| /* FieldID SEQUENCE */ |
| LTC_SET_ASN1(seq_fieldid, 0, LTC_ASN1_OBJECT_IDENTIFIER, oid, oidlen); |
| 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, len_a); |
| LTC_SET_ASN1(seq_curve, 1, LTC_ASN1_OCTET_STRING, bin_b, len_b); |
| |
| /* ECParameters SEQUENCE */ |
| LTC_SET_ASN1(seq_ecparams, 0, LTC_ASN1_SHORT_INTEGER, &one, 1UL); |
| LTC_SET_ASN1(seq_ecparams, 1, LTC_ASN1_SEQUENCE, seq_fieldid, 2UL); |
| LTC_SET_ASN1(seq_ecparams, 2, LTC_ASN1_SEQUENCE, seq_curve, 2UL); |
| LTC_SET_ASN1(seq_ecparams, 3, LTC_ASN1_OCTET_STRING, bin_g, len_g); |
| LTC_SET_ASN1(seq_ecparams, 4, LTC_ASN1_INTEGER, order, 1UL); |
| LTC_SET_ASN1(seq_ecparams, 5, LTC_ASN1_SHORT_INTEGER, &cofactor, 1UL); |
| |
| /* ECParameters used by ECPrivateKey or SubjectPublicKeyInfo below */ |
| LTC_SET_ASN1(&ecparams, 0, LTC_ASN1_SEQUENCE, seq_ecparams, 6UL); |
| } |
| |
| if (flag_pri) { |
| /* http://tools.ietf.org/html/rfc5915 |
| ECPrivateKey ::= SEQUENCE { # SEQUENCE |
| version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1) # INTEGER :01 |
| privateKey OCTET STRING, # OCTET STRING |
| [0] ECParameters # see above |
| [1] publicKey # BIT STRING |
| } |
| */ |
| |
| /* private key */ |
| len_k = mp_unsigned_bin_size(key->k); |
| if (len_k > sizeof(bin_k)) { err = CRYPT_BUFFER_OVERFLOW; goto error; } |
| if ((err = mp_to_unsigned_bin(key->k, bin_k)) != CRYPT_OK) { goto error; } |
| |
| LTC_SET_ASN1(&pub_xy, 0, LTC_ASN1_RAW_BIT_STRING, bin_xy, 8*len_xy); |
| LTC_SET_ASN1(seq_priv, 0, LTC_ASN1_SHORT_INTEGER, &one, 1); |
| LTC_SET_ASN1(seq_priv, 1, LTC_ASN1_OCTET_STRING, bin_k, len_k); |
| LTC_SET_ASN1_CUSTOM_CONSTRUCTED(seq_priv, 2, LTC_ASN1_CL_CONTEXT_SPECIFIC, 0, &ecparams); /* context specific 0 */ |
| LTC_SET_ASN1_CUSTOM_CONSTRUCTED(seq_priv, 3, LTC_ASN1_CL_CONTEXT_SPECIFIC, 1, &pub_xy); /* context specific 1 */ |
| |
| err = der_encode_sequence(seq_priv, 4, out, outlen); |
| } |
| else { |
| /* http://tools.ietf.org/html/rfc5480 |
| SubjectPublicKeyInfo ::= SEQUENCE { # SEQUENCE |
| AlgorithmIdentifier ::= SEQUENCE { # SEQUENCE |
| algorithm OBJECT IDENTIFIER # OBJECT :id-ecPublicKey |
| ECParameters # see above |
| } |
| subjectPublicKey BIT STRING # BIT STRING |
| } |
| */ |
| err = x509_encode_subject_public_key_info( out, outlen, PKA_EC, bin_xy, len_xy, |
| ecparams.type, ecparams.data, ecparams.size ); |
| } |
| |
| error: |
| return err; |
| } |
| |
| #endif |
| |
| /* ref: $Format:%D$ */ |
| /* git commit: $Format:%H$ */ |
| /* commit time: $Format:%ai$ */ |
