<?php
declare(strict_types=1);
/*
* The MIT License (MIT)
*
* Copyright (c) 2014-2018 Spomky-Labs
*
* This software may be modified and distributed under the terms
* of the MIT license. See the LICENSE file for details.
*/
namespace Jose\Component\Core\Util;
use Base64Url\Base64Url;
use InvalidArgumentException;
use Jose\Component\Core\JWK;
use Jose\Component\Core\Util\Ecc\Curve;
use Jose\Component\Core\Util\Ecc\NistCurve;
use RuntimeException;
use Throwable;
/**
* @internal
*/
class ECKey
{
public static function convertToPEM(JWK $jwk): string
{
if ($jwk->has('d')) {
return self::convertPrivateKeyToPEM($jwk);
}
return self::convertPublicKeyToPEM($jwk);
}
public static function convertPublicKeyToPEM(JWK $jwk): string
{
switch ($jwk->get('crv')) {
case 'P-256':
$der = self::p256PublicKey();
break;
case 'P-384':
$der = self::p384PublicKey();
break;
case 'P-521':
$der = self::p521PublicKey();
break;
default:
throw new InvalidArgumentException('Unsupported curve.');
}
$der .= self::getKey($jwk);
$pem = '-----BEGIN PUBLIC KEY-----'.PHP_EOL;
$pem .= chunk_split(base64_encode($der), 64, PHP_EOL);
$pem .= '-----END PUBLIC KEY-----'.PHP_EOL;
return $pem;
}
public static function convertPrivateKeyToPEM(JWK $jwk): string
{
switch ($jwk->get('crv')) {
case 'P-256':
$der = self::p256PrivateKey($jwk);
break;
case 'P-384':
$der = self::p384PrivateKey($jwk);
break;
case 'P-521':
$der = self::p521PrivateKey($jwk);
break;
default:
throw new InvalidArgumentException('Unsupported curve.');
}
$der .= self::getKey($jwk);
$pem = '-----BEGIN EC PRIVATE KEY-----'.PHP_EOL;
$pem .= chunk_split(base64_encode($der), 64, PHP_EOL);
$pem .= '-----END EC PRIVATE KEY-----'.PHP_EOL;
return $pem;
}
/**
* Creates a EC key with the given curve and additional values.
*
* @param string $curve The curve
* @param array $values values to configure the key
*/
public static function createECKey(string $curve, array $values = []): JWK
{
try {
$jwk = self::createECKeyUsingOpenSSL($curve);
} catch (Throwable $e) {
$jwk = self::createECKeyUsingPurePhp($curve);
}
$values = array_merge($values, $jwk);
return new JWK($values);
}
private static function getNistCurve(string $curve): Curve
{
switch ($curve) {
case 'P-256':
return NistCurve::curve256();
case 'P-384':
return NistCurve::curve384();
case 'P-521':
return NistCurve::curve521();
default:
throw new InvalidArgumentException(sprintf('The curve "%s" is not supported.', $curve));
}
}
private static function getNistCurveSize(string $curve): int
{
switch ($curve) {
case 'P-256':
return 256;
case 'P-384':
return 384;
case 'P-521':
return 521;
default:
throw new InvalidArgumentException(sprintf('The curve "%s" is not supported.', $curve));
}
}
private static function createECKeyUsingPurePhp(string $curve): array
{
$nistCurve = self::getNistCurve($curve);
$privateKey = $nistCurve->createPrivateKey();
$publicKey = $nistCurve->createPublicKey($privateKey);
return [
'kty' => 'EC',
'crv' => $curve,
'x' => Base64Url::encode(str_pad(gmp_export($publicKey->getPoint()->getX()), (int) ceil($nistCurve->getSize() / 8), "\0", STR_PAD_LEFT)),
'y' => Base64Url::encode(str_pad(gmp_export($publicKey->getPoint()->getY()), (int) ceil($nistCurve->getSize() / 8), "\0", STR_PAD_LEFT)),
'd' => Base64Url::encode(str_pad(gmp_export($privateKey->getSecret()), (int) ceil($nistCurve->getSize() / 8), "\0", STR_PAD_LEFT)),
];
}
private static function createECKeyUsingOpenSSL(string $curve): array
{
$key = openssl_pkey_new([
'curve_name' => self::getOpensslCurveName($curve),
'private_key_type' => OPENSSL_KEYTYPE_EC,
]);
if (false === $key) {
throw new RuntimeException('Unable to create the key');
}
$result = openssl_pkey_export($key, $out);
if (false === $result) {
throw new RuntimeException('Unable to create the key');
}
$res = openssl_pkey_get_private($out);
if (false === $res) {
throw new RuntimeException('Unable to create the key');
}
$details = openssl_pkey_get_details($res);
$nistCurveSize = self::getNistCurveSize($curve);
return [
'kty' => 'EC',
'crv' => $curve,
'd' => Base64Url::encode(str_pad($details['ec']['d'], (int) ceil($nistCurveSize / 8), "\0", STR_PAD_LEFT)),
'x' => Base64Url::encode(str_pad($details['ec']['x'], (int) ceil($nistCurveSize / 8), "\0", STR_PAD_LEFT)),
'y' => Base64Url::encode(str_pad($details['ec']['y'], (int) ceil($nistCurveSize / 8), "\0", STR_PAD_LEFT)),
];
}
private static function getOpensslCurveName(string $curve): string
{
switch ($curve) {
case 'P-256':
return 'prime256v1';
case 'P-384':
return 'secp384r1';
case 'P-521':
return 'secp521r1';
default:
throw new InvalidArgumentException(sprintf('The curve "%s" is not supported.', $curve));
}
}
private static function p256PublicKey(): string
{
return pack(
'H*',
'3059' // SEQUENCE, length 89
.'3013' // SEQUENCE, length 19
.'0607' // OID, length 7
.'2a8648ce3d0201' // 1.2.840.10045.2.1 = EC Public Key
.'0608' // OID, length 8
.'2a8648ce3d030107' // 1.2.840.10045.3.1.7 = P-256 Curve
.'0342' // BIT STRING, length 66
.'00' // prepend with NUL - pubkey will follow
);
}
private static function p384PublicKey(): string
{
return pack(
'H*',
'3076' // SEQUENCE, length 118
.'3010' // SEQUENCE, length 16
.'0607' // OID, length 7
.'2a8648ce3d0201' // 1.2.840.10045.2.1 = EC Public Key
.'0605' // OID, length 5
.'2b81040022' // 1.3.132.0.34 = P-384 Curve
.'0362' // BIT STRING, length 98
.'00' // prepend with NUL - pubkey will follow
);
}
private static function p521PublicKey(): string
{
return pack(
'H*',
'30819b' // SEQUENCE, length 154
.'3010' // SEQUENCE, length 16
.'0607' // OID, length 7
.'2a8648ce3d0201' // 1.2.840.10045.2.1 = EC Public Key
.'0605' // OID, length 5
.'2b81040023' // 1.3.132.0.35 = P-521 Curve
.'038186' // BIT STRING, length 134
.'00' // prepend with NUL - pubkey will follow
);
}
private static function p256PrivateKey(JWK $jwk): string
{
$d = unpack('H*', str_pad(Base64Url::decode($jwk->get('d')), 32, "\0", STR_PAD_LEFT))[1];
return pack(
'H*',
'3077' // SEQUENCE, length 87+length($d)=32
.'020101' // INTEGER, 1
.'0420' // OCTET STRING, length($d) = 32
.$d
.'a00a' // TAGGED OBJECT #0, length 10
.'0608' // OID, length 8
.'2a8648ce3d030107' // 1.3.132.0.34 = P-384 Curve
.'a144' // TAGGED OBJECT #1, length 68
.'0342' // BIT STRING, length 66
.'00' // prepend with NUL - pubkey will follow
);
}
private static function p384PrivateKey(JWK $jwk): string
{
$d = unpack('H*', str_pad(Base64Url::decode($jwk->get('d')), 48, "\0", STR_PAD_LEFT))[1];
return pack(
'H*',
'3081a4' // SEQUENCE, length 116 + length($d)=48
.'020101' // INTEGER, 1
.'0430' // OCTET STRING, length($d) = 30
.$d
.'a007' // TAGGED OBJECT #0, length 7
.'0605' // OID, length 5
.'2b81040022' // 1.3.132.0.34 = P-384 Curve
.'a164' // TAGGED OBJECT #1, length 100
.'0362' // BIT STRING, length 98
.'00' // prepend with NUL - pubkey will follow
);
}
private static function p521PrivateKey(JWK $jwk): string
{
$d = unpack('H*', str_pad(Base64Url::decode($jwk->get('d')), 66, "\0", STR_PAD_LEFT))[1];
return pack(
'H*',
'3081dc' // SEQUENCE, length 154 + length($d)=66
.'020101' // INTEGER, 1
.'0442' // OCTET STRING, length(d) = 66
.$d
.'a007' // TAGGED OBJECT #0, length 7
.'0605' // OID, length 5
.'2b81040023' // 1.3.132.0.35 = P-521 Curve
.'a18189' // TAGGED OBJECT #1, length 137
.'038186' // BIT STRING, length 134
.'00' // prepend with NUL - pubkey will follow
);
}
private static function getKey(JWK $jwk): string
{
$nistCurveSize = self::getNistCurveSize($jwk->get('crv'));
$length = (int) ceil($nistCurveSize / 8);
return
"\04"
.str_pad(Base64Url::decode($jwk->get('x')), $length, "\0", STR_PAD_LEFT)
.str_pad(Base64Url::decode($jwk->get('y')), $length, "\0", STR_PAD_LEFT);
}
}