<?php
namespace Firebase\JWT;
use DomainException;
use InvalidArgumentException;
use UnexpectedValueException;
/**
* JSON Web Key implementation, based on this spec:
* https://tools.ietf.org/html/draft-ietf-jose-json-web-key-41
*
* PHP version 5
*
* @category Authentication
* @package Authentication_JWT
* @author Bui Sy Nguyen <nguyenbs@gmail.com>
* @license http://opensource.org/licenses/BSD-3-Clause 3-clause BSD
* @link https://github.com/firebase/php-jwt
*/
class JWK
{
private const OID = '1.2.840.10045.2.1';
private const ASN1_OBJECT_IDENTIFIER = 0x06;
private const ASN1_SEQUENCE = 0x10; // also defined in JWT
private const ASN1_BIT_STRING = 0x03;
private const EC_CURVES = [
'P-256' => '1.2.840.10045.3.1.7', // Len: 64
'secp256k1' => '1.3.132.0.10', // Len: 64
'P-384' => '1.3.132.0.34', // Len: 96
// 'P-521' => '1.3.132.0.35', // Len: 132 (not supported)
];
// For keys with "kty" equal to "OKP" (Octet Key Pair), the "crv" parameter must contain the key subtype.
// This library supports the following subtypes:
private const OKP_SUBTYPES = [
'Ed25519' => true, // RFC 8037
];
/**
* Parse a set of JWK keys
*
* @param array<mixed> $jwks The JSON Web Key Set as an associative array
* @param string $defaultAlg The algorithm for the Key object if "alg" is not set in the
* JSON Web Key Set
*
* @return array<string, Key> An associative array of key IDs (kid) to Key objects
*
* @throws InvalidArgumentException Provided JWK Set is empty
* @throws UnexpectedValueException Provided JWK Set was invalid
* @throws DomainException OpenSSL failure
*
* @uses parseKey
*/
public static function parseKeySet(array $jwks, string $defaultAlg = null): array
{
$keys = [];
if (!isset($jwks['keys'])) {
throw new UnexpectedValueException('"keys" member must exist in the JWK Set');
}
if (empty($jwks['keys'])) {
throw new InvalidArgumentException('JWK Set did not contain any keys');
}
foreach ($jwks['keys'] as $k => $v) {
$kid = isset($v['kid']) ? $v['kid'] : $k;
if ($key = self::parseKey($v, $defaultAlg)) {
$keys[(string) $kid] = $key;
}
}
if (0 === \count($keys)) {
throw new UnexpectedValueException('No supported algorithms found in JWK Set');
}
return $keys;
}
/**
* Parse a JWK key
*
* @param array<mixed> $jwk An individual JWK
* @param string $defaultAlg The algorithm for the Key object if "alg" is not set in the
* JSON Web Key Set
*
* @return Key The key object for the JWK
*
* @throws InvalidArgumentException Provided JWK is empty
* @throws UnexpectedValueException Provided JWK was invalid
* @throws DomainException OpenSSL failure
*
* @uses createPemFromModulusAndExponent
*/
public static function parseKey(array $jwk, string $defaultAlg = null): ?Key
{
if (empty($jwk)) {
throw new InvalidArgumentException('JWK must not be empty');
}
if (!isset($jwk['kty'])) {
throw new UnexpectedValueException('JWK must contain a "kty" parameter');
}
if (!isset($jwk['alg'])) {
if (\is_null($defaultAlg)) {
// The "alg" parameter is optional in a KTY, but an algorithm is required
// for parsing in this library. Use the $defaultAlg parameter when parsing the
// key set in order to prevent this error.
// @see https://datatracker.ietf.org/doc/html/rfc7517#section-4.4
throw new UnexpectedValueException('JWK must contain an "alg" parameter');
}
$jwk['alg'] = $defaultAlg;
}
switch ($jwk['kty']) {
case 'RSA':
if (!empty($jwk['d'])) {
throw new UnexpectedValueException('RSA private keys are not supported');
}
if (!isset($jwk['n']) || !isset($jwk['e'])) {
throw new UnexpectedValueException('RSA keys must contain values for both "n" and "e"');
}
$pem = self::createPemFromModulusAndExponent($jwk['n'], $jwk['e']);
$publicKey = \openssl_pkey_get_public($pem);
if (false === $publicKey) {
throw new DomainException(
'OpenSSL error: ' . \openssl_error_string()
);
}
return new Key($publicKey, $jwk['alg']);
case 'EC':
if (isset($jwk['d'])) {
// The key is actually a private key
throw new UnexpectedValueException('Key data must be for a public key');
}
if (empty($jwk['crv'])) {
throw new UnexpectedValueException('crv not set');
}
if (!isset(self::EC_CURVES[$jwk['crv']])) {
throw new DomainException('Unrecognised or unsupported EC curve');
}
if (empty($jwk['x']) || empty($jwk['y'])) {
throw new UnexpectedValueException('x and y not set');
}
$publicKey = self::createPemFromCrvAndXYCoordinates($jwk['crv'], $jwk['x'], $jwk['y']);
return new Key($publicKey, $jwk['alg']);
case 'OKP':
if (isset($jwk['d'])) {
// The key is actually a private key
throw new UnexpectedValueException('Key data must be for a public key');
}
if (!isset($jwk['crv'])) {
throw new UnexpectedValueException('crv not set');
}
if (empty(self::OKP_SUBTYPES[$jwk['crv']])) {
throw new DomainException('Unrecognised or unsupported OKP key subtype');
}
if (empty($jwk['x'])) {
throw new UnexpectedValueException('x not set');
}
// This library works internally with EdDSA keys (Ed25519) encoded in standard base64.
$publicKey = JWT::convertBase64urlToBase64($jwk['x']);
return new Key($publicKey, $jwk['alg']);
default:
break;
}
return null;
}
/**
* Converts the EC JWK values to pem format.
*
* @param string $crv The EC curve (only P-256 & P-384 is supported)
* @param string $x The EC x-coordinate
* @param string $y The EC y-coordinate
*
* @return string
*/
private static function createPemFromCrvAndXYCoordinates(string $crv, string $x, string $y): string
{
$pem =
self::encodeDER(
self::ASN1_SEQUENCE,
self::encodeDER(
self::ASN1_SEQUENCE,
self::encodeDER(
self::ASN1_OBJECT_IDENTIFIER,
self::encodeOID(self::OID)
)
. self::encodeDER(
self::ASN1_OBJECT_IDENTIFIER,
self::encodeOID(self::EC_CURVES[$crv])
)
) .
self::encodeDER(
self::ASN1_BIT_STRING,
\chr(0x00) . \chr(0x04)
. JWT::urlsafeB64Decode($x)
. JWT::urlsafeB64Decode($y)
)
);
return sprintf(
"-----BEGIN PUBLIC KEY-----\n%s\n-----END PUBLIC KEY-----\n",
wordwrap(base64_encode($pem), 64, "\n", true)
);
}
/**
* Create a public key represented in PEM format from RSA modulus and exponent information
*
* @param string $n The RSA modulus encoded in Base64
* @param string $e The RSA exponent encoded in Base64
*
* @return string The RSA public key represented in PEM format
*
* @uses encodeLength
*/
private static function createPemFromModulusAndExponent(
string $n,
string $e
): string {
$mod = JWT::urlsafeB64Decode($n);
$exp = JWT::urlsafeB64Decode($e);
$modulus = \pack('Ca*a*', 2, self::encodeLength(\strlen($mod)), $mod);
$publicExponent = \pack('Ca*a*', 2, self::encodeLength(\strlen($exp)), $exp);
$rsaPublicKey = \pack(
'Ca*a*a*',
48,
self::encodeLength(\strlen($modulus) + \strlen($publicExponent)),
$modulus,
$publicExponent
);
// sequence(oid(1.2.840.113549.1.1.1), null)) = rsaEncryption.
$rsaOID = \pack('H*', '300d06092a864886f70d0101010500'); // hex version of MA0GCSqGSIb3DQEBAQUA
$rsaPublicKey = \chr(0) . $rsaPublicKey;
$rsaPublicKey = \chr(3) . self::encodeLength(\strlen($rsaPublicKey)) . $rsaPublicKey;
$rsaPublicKey = \pack(
'Ca*a*',
48,
self::encodeLength(\strlen($rsaOID . $rsaPublicKey)),
$rsaOID . $rsaPublicKey
);
return "-----BEGIN PUBLIC KEY-----\r\n" .
\chunk_split(\base64_encode($rsaPublicKey), 64) .
'-----END PUBLIC KEY-----';
}
/**
* DER-encode the length
*
* DER supports lengths up to (2**8)**127, however, we'll only support lengths up to (2**8)**4. See
* {@link http://itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf#p=13 X.690 paragraph 8.1.3} for more information.
*
* @param int $length
* @return string
*/
private static function encodeLength(int $length): string
{
if ($length <= 0x7F) {
return \chr($length);
}
$temp = \ltrim(\pack('N', $length), \chr(0));
return \pack('Ca*', 0x80 | \strlen($temp), $temp);
}
/**
* Encodes a value into a DER object.
* Also defined in Firebase\JWT\JWT
*
* @param int $type DER tag
* @param string $value the value to encode
* @return string the encoded object
*/
private static function encodeDER(int $type, string $value): string
{
$tag_header = 0;
if ($type === self::ASN1_SEQUENCE) {
$tag_header |= 0x20;
}
// Type
$der = \chr($tag_header | $type);
// Length
$der .= \chr(\strlen($value));
return $der . $value;
}
/**
* Encodes a string into a DER-encoded OID.
*
* @param string $oid the OID string
* @return string the binary DER-encoded OID
*/
private static function encodeOID(string $oid): string
{
$octets = explode('.', $oid);
// Get the first octet
$first = (int) array_shift($octets);
$second = (int) array_shift($octets);
$oid = \chr($first * 40 + $second);
// Iterate over subsequent octets
foreach ($octets as $octet) {
if ($octet == 0) {
$oid .= \chr(0x00);
continue;
}
$bin = '';
while ($octet) {
$bin .= \chr(0x80 | ($octet & 0x7f));
$octet >>= 7;
}
$bin[0] = $bin[0] & \chr(0x7f);
// Convert to big endian if necessary
if (pack('V', 65534) == pack('L', 65534)) {
$oid .= strrev($bin);
} else {
$oid .= $bin;
}
}
return $oid;
}
}
NFC Pay was founded with a vision to transform the way people handle transactions. Our journey is defined by a commitment to innovation, security, and convenience. We strive to deliver seamless, user-friendly payment solutions that make everyday transactions effortless and secure. Our mission is to empower you to pay with ease and confidence, anytime, anywhere.
Simplifying Payments, One Tap at a Time.
Reinventing Your Wallet for Modern Convenience.
Smart Payments for a Effortless Lifestyle.
Experience the Ease of Tap and Pay.
Innovative Solutions for Your Daily Transactions.
FAQ Section
Frequently Asked Questions About NFC Pay
Here are answers to some common questions about NFC Pay. We aim to provide clear and concise information to help you understand how our platform works and how it can benefit you. If you have any further inquiries, please don’t hesitate to contact our support team.
How do I register for NFC Pay?
Download the app and sign up using your email or phone number, then complete the verification process.
Is my payment information secure?
Yes, we use advanced encryption and security protocols to protect your payment details.
Can I add multiple cards to my NFC Pay wallet?
Absolutely, you can link multiple debit or credit cards to your wallet.
How do I transfer money to another user?
Go to the transfer section, select the recipient, enter the amount, and authorize the transfer.
What should I do if I forget my PIN?
Use the “Forgot PIN” feature in the app to reset it following the provided instructions.
How can I activate my merchant account?
Sign up for a merchant account through the app and follow the setup instructions to start accepting payments.
Can I track my payment status?
Yes, you can view and track your payment status in the account dashboard
In the digital age, privacy concerns have become increasingly paramount, prompting the European Union to enact the General Data Protection Regulation (GDPR) in 2018. Among its many provisions, GDPR sets strict guidelines for the collection and processing of personal data, including the use of cookies on websites. Privacy Policy
