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/*
* Copyright (c) 2018 Thomas Pornin <pornin@bolet.org>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "inner.h"
/* see bearssl_x509.h */
size_t
br_encode_ec_pkcs8_der(void *dest,
const br_ec_private_key *sk, const br_ec_public_key *pk)
{
/*
* ASN.1 format:
*
* OneAsymmetricKey ::= SEQUENCE {
* version Version,
* privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
* privateKey PrivateKey,
* attributes [0] Attributes OPTIONAL,
* ...,
* [[2: publicKey [1] PublicKey OPTIONAL ]],
* ...
* }
*
* We don't include attributes or public key (the public key
* is included in the private key value instead). The
* 'version' field is an INTEGER that we will set to 0
* (meaning 'v1', compatible with previous versions of PKCS#8).
* The 'privateKeyAlgorithm' structure is an AlgorithmIdentifier
* whose OID should be id-ecPublicKey, with, as parameters, the
* curve OID. The 'privateKey' is an OCTET STRING, whose value
* is the "raw DER" encoding of the key pair.
*/
/*
* OID id-ecPublicKey (1.2.840.10045.2.1), DER-encoded (with
* the tag).
*/
static const unsigned char OID_ECPUBKEY[] = {
0x06, 0x07, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x02, 0x01
};
size_t len_version, len_privateKeyAlgorithm, len_privateKeyValue;
size_t len_privateKey, len_seq;
const unsigned char *oid;
oid = br_get_curve_OID(sk->curve);
if (oid == NULL) {
return 0;
}
len_version = 3;
len_privateKeyAlgorithm = 2 + sizeof OID_ECPUBKEY + 2 + oid[0];
len_privateKeyValue = br_encode_ec_raw_der_inner(NULL, sk, pk, 0);
len_privateKey = 1 + len_of_len(len_privateKeyValue)
+ len_privateKeyValue;
len_seq = len_version + len_privateKeyAlgorithm + len_privateKey;
if (dest == NULL) {
return 1 + len_of_len(len_seq) + len_seq;
} else {
unsigned char *buf;
size_t lenlen;
buf = dest;
*buf ++ = 0x30; /* SEQUENCE tag */
lenlen = br_asn1_encode_length(buf, len_seq);
buf += lenlen;
/* version */
*buf ++ = 0x02;
*buf ++ = 0x01;
*buf ++ = 0x00;
/* privateKeyAlgorithm */
*buf ++ = 0x30;
*buf ++ = (sizeof OID_ECPUBKEY) + 2 + oid[0];
memcpy(buf, OID_ECPUBKEY, sizeof OID_ECPUBKEY);
buf += sizeof OID_ECPUBKEY;
*buf ++ = 0x06;
memcpy(buf, oid, 1 + oid[0]);
buf += 1 + oid[0];
/* privateKey */
*buf ++ = 0x04;
buf += br_asn1_encode_length(buf, len_privateKeyValue);
br_encode_ec_raw_der_inner(buf, sk, pk, 0);
return 1 + lenlen + len_seq;
}
}
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