<?php

namespace Firebase\JWT;


< use \DomainException;
< use \InvalidArgumentException;
< use \UnexpectedValueException;
< use \DateTime;



> use ArrayAccess;
> use DateTime;
> use DomainException;
> use Exception;
> use InvalidArgumentException;
> use OpenSSLAsymmetricKey;
> use OpenSSLCertificate;
> use stdClass;
> use UnexpectedValueException;



/**
 * JSON Web Token implementation, based on this spec:
 * https://tools.ietf.org/html/rfc7519
 *
 * PHP version 5
 *
 * @category Authentication
 * @package  Authentication_JWT
 * @author   Neuman Vong <neuman@twilio.com>
 * @author   Anant Narayanan <anant@php.net>
 * @license  http://opensource.org/licenses/BSD-3-Clause 3-clause BSD
 * @link     https://github.com/firebase/php-jwt
 */
class JWT
{

<     const ASN1_INTEGER = 0x02;
<     const ASN1_SEQUENCE = 0x10;
<     const ASN1_BIT_STRING = 0x03;



>     private const ASN1_INTEGER = 0x02;
>     private const ASN1_SEQUENCE = 0x10;
>     private const ASN1_BIT_STRING = 0x03;



    /**
     * When checking nbf, iat or expiration times,
     * we want to provide some extra leeway time to
     * account for clock skew.

>      *
     */
>      * @var int



<     public static $leeway = 180;



>     public static $leeway = 0;



    /**
     * Allow the current timestamp to be specified.
     * Useful for fixing a value within unit testing.

<      *


     * Will default to PHP time() value if null.

>      *
     */
>      * @var ?int


    public static $timestamp = null;


<     public static $supported_algs = array(
<         'ES256' => array('openssl', 'SHA256'),
<         'HS256' => array('hash_hmac', 'SHA256'),
<         'HS384' => array('hash_hmac', 'SHA384'),
<         'HS512' => array('hash_hmac', 'SHA512'),
<         'RS256' => array('openssl', 'SHA256'),
<         'RS384' => array('openssl', 'SHA384'),
<         'RS512' => array('openssl', 'SHA512'),
<     );



>     /**
>      * @var array<string, string[]>
>      */
>     public static $supported_algs = [
>         'ES384' => ['openssl', 'SHA384'],
>         'ES256' => ['openssl', 'SHA256'],
>         'ES256K' => ['openssl', 'SHA256'],
>         'HS256' => ['hash_hmac', 'SHA256'],
>         'HS384' => ['hash_hmac', 'SHA384'],
>         'HS512' => ['hash_hmac', 'SHA512'],
>         'RS256' => ['openssl', 'SHA256'],
>         'RS384' => ['openssl', 'SHA384'],
>         'RS512' => ['openssl', 'SHA512'],
>         'EdDSA' => ['sodium_crypto', 'EdDSA'],
>     ];



    /**
     * Decodes a JWT string into a PHP object.
     *
     * @param string                    $jwt            The JWT

<      * @param string|array|resource     $key            The key, or map of keys.



>      * @param Key|array<string,Key> $keyOrKeyArray  The Key or associative array of key IDs (kid) to Key objects.


     *                                                  If the algorithm used is asymmetric, this is the public key

<      * @param array                     $allowed_algs   List of supported verification algorithms
<      *                                                  Supported algorithms are 'ES256', 'HS256', 'HS384', 'HS512', 'RS256', 'RS384', and 'RS512'



>      *                                               Each Key object contains an algorithm and matching key.
>      *                                               Supported algorithms are 'ES384','ES256', 'HS256', 'HS384',
>      *                                               'HS512', 'RS256', 'RS384', and 'RS512'


     *

<      * @return object The JWT's payload as a PHP object



>      * @return stdClass The JWT's payload as a PHP object


     *

>      * @throws InvalidArgumentException     Provided key/key-array was empty or malformed
     * @throws UnexpectedValueException     Provided JWT was invalid
>      * @throws DomainException              Provided JWT is malformed


     * @throws SignatureInvalidException    Provided JWT was invalid because the signature verification failed
     * @throws BeforeValidException         Provided JWT is trying to be used before it's eligible as defined by 'nbf'
     * @throws BeforeValidException         Provided JWT is trying to be used before it's been created as defined by 'iat'
     * @throws ExpiredException             Provided JWT has since expired, as defined by the 'exp' claim
     *
     * @uses jsonDecode
     * @uses urlsafeB64Decode
     */

<     public static function decode($jwt, $key, array $allowed_algs = array())
<     {



>     public static function decode(
>         string $jwt,
>         $keyOrKeyArray
>     ): stdClass {
>         // Validate JWT


        $timestamp = \is_null(static::$timestamp) ? \time() : static::$timestamp;


<         if (empty($key)) {



>         if (empty($keyOrKeyArray)) {


            throw new InvalidArgumentException('Key may not be empty');
        }
        $tks = \explode('.', $jwt);

<         if (\count($tks) != 3) {



>         if (\count($tks) !== 3) {


            throw new UnexpectedValueException('Wrong number of segments');
        }
        list($headb64, $bodyb64, $cryptob64) = $tks;

<         if (null === ($header = static::jsonDecode(static::urlsafeB64Decode($headb64)))) {



>         $headerRaw = static::urlsafeB64Decode($headb64);
>         if (null === ($header = static::jsonDecode($headerRaw))) {


            throw new UnexpectedValueException('Invalid header encoding');
        }

<         if (null === $payload = static::jsonDecode(static::urlsafeB64Decode($bodyb64))) {



>         $payloadRaw = static::urlsafeB64Decode($bodyb64);
>         if (null === ($payload = static::jsonDecode($payloadRaw))) {


            throw new UnexpectedValueException('Invalid claims encoding');
        }

<         if (false === ($sig = static::urlsafeB64Decode($cryptob64))) {
<             throw new UnexpectedValueException('Invalid signature encoding');



>         if (\is_array($payload)) {
>             // prevent PHP Fatal Error in edge-cases when payload is empty array
>             $payload = (object) $payload;
>         }
>         if (!$payload instanceof stdClass) {
>             throw new UnexpectedValueException('Payload must be a JSON object');


        }

>         $sig = static::urlsafeB64Decode($cryptob64);


        if (empty($header->alg)) {
            throw new UnexpectedValueException('Empty algorithm');
        }
        if (empty(static::$supported_algs[$header->alg])) {
            throw new UnexpectedValueException('Algorithm not supported');
        }

<         if (!\in_array($header->alg, $allowed_algs)) {
<             throw new UnexpectedValueException('Algorithm not allowed');
<         }
<         if ($header->alg === 'ES256') {
<             // OpenSSL expects an ASN.1 DER sequence for ES256 signatures
<             $sig = self::signatureToDER($sig);
<         }




<         if (\is_array($key) || $key instanceof \ArrayAccess) {
<             if (isset($header->kid)) {
<                 if (!isset($key[$header->kid])) {
<                     throw new UnexpectedValueException('"kid" invalid, unable to lookup correct key');
<                 }
<                 $key = $key[$header->kid];
<             } else {
<                 throw new UnexpectedValueException('"kid" empty, unable to lookup correct key');



>         $key = self::getKey($keyOrKeyArray, property_exists($header, 'kid') ? $header->kid : null);
> 
>         // Check the algorithm
>         if (!self::constantTimeEquals($key->getAlgorithm(), $header->alg)) {
>             // See issue #351
>             throw new UnexpectedValueException('Incorrect key for this algorithm');


            }

>         if (\in_array($header->alg, ['ES256', 'ES256K', 'ES384'], true)) {
        }
>             // OpenSSL expects an ASN.1 DER sequence for ES256/ES256K/ES384 signatures

>             $sig = self::signatureToDER($sig);



< 
<         // Check the signature
<         if (!static::verify("$headb64.$bodyb64", $sig, $key, $header->alg)) {



>         if (!self::verify("{$headb64}.{$bodyb64}", $sig, $key->getKeyMaterial(), $header->alg)) {


        }

        // Check the nbf if it is defined. This is the time that the
        // token can actually be used. If it's not yet that time, abort.
        if (isset($payload->nbf) && $payload->nbf > ($timestamp + static::$leeway)) {
            throw new BeforeValidException(
                'Cannot handle token prior to ' . \date(DateTime::ISO8601, $payload->nbf)
            );
        }

        // Check that this token has been created before 'now'. This prevents
        // using tokens that have been created for later use (and haven't
        // correctly used the nbf claim).
        if (isset($payload->iat) && $payload->iat > ($timestamp + static::$leeway)) {
            throw new BeforeValidException(
                'Cannot handle token prior to ' . \date(DateTime::ISO8601, $payload->iat)
            );
        }

        // Check if this token has expired.
        if (isset($payload->exp) && ($timestamp - static::$leeway) >= $payload->exp) {
            throw new ExpiredException('Expired token');
        }

        return $payload;
    }

    /**

<      * Converts and signs a PHP object or array into a JWT string.



>      * Converts and signs a PHP array into a JWT string.


     *

<      * @param object|array  $payload    PHP object or array
<      * @param string        $key        The secret key.
<      *                                  If the algorithm used is asymmetric, this is the private key
<      * @param string        $alg        The signing algorithm.
<      *                                  Supported algorithms are 'ES256', 'HS256', 'HS384', 'HS512', 'RS256', 'RS384', and 'RS512'
<      * @param mixed         $keyId
<      * @param array         $head       An array with header elements to attach



>      * @param array<mixed>          $payload PHP array
>      * @param string|resource|OpenSSLAsymmetricKey|OpenSSLCertificate $key The secret key.
>      * @param string                $alg     Supported algorithms are 'ES384','ES256', 'ES256K', 'HS256',
>      *                                       'HS384', 'HS512', 'RS256', 'RS384', and 'RS512'
>      * @param string                $keyId
>      * @param array<string, string> $head    An array with header elements to attach


     *
     * @return string A signed JWT
     *
     * @uses jsonEncode
     * @uses urlsafeB64Encode
     */

<     public static function encode($payload, $key, $alg = 'HS256', $keyId = null, $head = null)
<     {
<         $header = array('typ' => 'JWT', 'alg' => $alg);



>     public static function encode(
>         array $payload,
>         $key,
>         string $alg,
>         string $keyId = null,
>         array $head = null
>     ): string {
>         $header = ['typ' => 'JWT', 'alg' => $alg];


        if ($keyId !== null) {
            $header['kid'] = $keyId;
        }
        if (isset($head) && \is_array($head)) {
            $header = \array_merge($head, $header);
        }

<         $segments = array();
<         $segments[] = static::urlsafeB64Encode(static::jsonEncode($header));
<         $segments[] = static::urlsafeB64Encode(static::jsonEncode($payload));



>         $segments = [];
>         $segments[] = static::urlsafeB64Encode((string) static::jsonEncode($header));
>         $segments[] = static::urlsafeB64Encode((string) static::jsonEncode($payload));


        $signing_input = \implode('.', $segments);

        $signature = static::sign($signing_input, $key, $alg);
        $segments[] = static::urlsafeB64Encode($signature);

        return \implode('.', $segments);
    }

    /**
     * Sign a string with a given key and algorithm.
     *
     * @param string            $msg    The message to sign

<      * @param string|resource   $key    The secret key
<      * @param string            $alg    The signing algorithm.
<      *                                  Supported algorithms are 'ES256', 'HS256', 'HS384', 'HS512', 'RS256', 'RS384', and 'RS512'



>      * @param string|resource|OpenSSLAsymmetricKey|OpenSSLCertificate  $key  The secret key.
>      * @param string $alg  Supported algorithms are 'ES384','ES256', 'ES256K', 'HS256',
>      *                    'HS384', 'HS512', 'RS256', 'RS384', and 'RS512'


     *
     * @return string An encrypted message
     *

<      * @throws DomainException Unsupported algorithm was specified



>      * @throws DomainException Unsupported algorithm or bad key was specified


     */

<     public static function sign($msg, $key, $alg = 'HS256')
<     {



>     public static function sign(
>         string $msg,
>         $key,
>         string $alg
>     ): string {


        if (empty(static::$supported_algs[$alg])) {
            throw new DomainException('Algorithm not supported');
        }
        list($function, $algorithm) = static::$supported_algs[$alg];
        switch ($function) {
            case 'hash_hmac':

>                 if (!\is_string($key)) {
                return \hash_hmac($algorithm, $msg, $key, true);
>                     throw new InvalidArgumentException('key must be a string when using hmac');
            case 'openssl':
>                 }


                $signature = '';

<                 $success = \openssl_sign($msg, $signature, $key, $algorithm);



>                 $success = \openssl_sign($msg, $signature, $key, $algorithm); // @phpstan-ignore-line


                if (!$success) {

<                     throw new DomainException("OpenSSL unable to sign data");
<                 } else {
<                     if ($alg === 'ES256') {



>                     throw new DomainException('OpenSSL unable to sign data');
>                 }
>                 if ($alg === 'ES256' || $alg === 'ES256K') {


                        $signature = self::signatureFromDER($signature, 256);

>                 } elseif ($alg === 'ES384') {
                    }
>                     $signature = self::signatureFromDER($signature, 384);


                    return $signature;

>             case 'sodium_crypto':
                }
>                 if (!\function_exists('sodium_crypto_sign_detached')) {
        }
>                     throw new DomainException('libsodium is not available');
    }
>                 }

>                 if (!\is_string($key)) {
    /**
>                     throw new InvalidArgumentException('key must be a string when using EdDSA');
     * Verify a signature with the message, key and method. Not all methods
>                 }
     * are symmetric, so we must have a separate verify and sign method.
>                 try {
     *
>                     // The last non-empty line is used as the key.
     * @param string            $msg        The original message (header and body)
>                     $lines = array_filter(explode("\n", $key));
     * @param string            $signature  The original signature
>                     $key = base64_decode((string) end($lines));
     * @param string|resource   $key        For HS*, a string key works. for RS*, must be a resource of an openssl public key
>                     if (\strlen($key) === 0) {
     * @param string            $alg        The algorithm
>                         throw new DomainException('Key cannot be empty string');
     *
>                     }
     * @return bool
>                     return sodium_crypto_sign_detached($msg, $key);
     *
>                 } catch (Exception $e) {
     * @throws DomainException Invalid Algorithm or OpenSSL failure
>                     throw new DomainException($e->getMessage(), 0, $e);


     */

> 
    private static function verify($msg, $signature, $key, $alg)
>         throw new DomainException('Algorithm not supported');



<      * @param string|resource   $key        For HS*, a string key works. for RS*, must be a resource of an openssl public key



>      * @param string|resource|OpenSSLAsymmetricKey|OpenSSLCertificate  $keyMaterial For HS*, a string key works. for RS*, must be an instance of OpenSSLAsymmetricKey



<      * @throws DomainException Invalid Algorithm or OpenSSL failure



>      * @throws DomainException Invalid Algorithm, bad key, or OpenSSL failure



<     private static function verify($msg, $signature, $key, $alg)
<     {



>     private static function verify(
>         string $msg,
>         string $signature,
>         $keyMaterial,
>         string $alg
>     ): bool {



        list($function, $algorithm) = static::$supported_algs[$alg];
        switch ($function) {
            case 'openssl':

<                 $success = \openssl_verify($msg, $signature, $key, $algorithm);



>                 $success = \openssl_verify($msg, $signature, $keyMaterial, $algorithm); // @phpstan-ignore-line


                if ($success === 1) {
                    return true;

<                 } elseif ($success === 0) {



>                 }
>                 if ($success === 0) {


                    return false;
                }
                // returns 1 on success, 0 on failure, -1 on error.
                throw new DomainException(
                    'OpenSSL error: ' . \openssl_error_string()
                );

>             case 'sodium_crypto':
            case 'hash_hmac':
>                 if (!\function_exists('sodium_crypto_sign_verify_detached')) {
            default:
>                     throw new DomainException('libsodium is not available');
                $hash = \hash_hmac($algorithm, $msg, $key, true);
>                 }
                if (\function_exists('hash_equals')) {
>                 if (!\is_string($keyMaterial)) {
                    return \hash_equals($signature, $hash);
>                     throw new InvalidArgumentException('key must be a string when using EdDSA');
                }
>                 }
                $len = \min(static::safeStrlen($signature), static::safeStrlen($hash));
>                 try {

>                     // The last non-empty line is used as the key.
                $status = 0;
>                     $lines = array_filter(explode("\n", $keyMaterial));
                for ($i = 0; $i < $len; $i++) {
>                     $key = base64_decode((string) end($lines));
                    $status |= (\ord($signature[$i]) ^ \ord($hash[$i]));
>                     if (\strlen($key) === 0) {
                }
>                         throw new DomainException('Key cannot be empty string');
                $status |= (static::safeStrlen($signature) ^ static::safeStrlen($hash));
>                     }

>                     if (\strlen($signature) === 0) {
                return ($status === 0);
>                         throw new DomainException('Signature cannot be empty string');
        }
>                     }
    }
>                     return sodium_crypto_sign_verify_detached($signature, $msg, $key);

>                 } catch (Exception $e) {
    /**
>                     throw new DomainException($e->getMessage(), 0, $e);
     * Decode a JSON string into a PHP object.
>                 }



<                 $hash = \hash_hmac($algorithm, $msg, $key, true);
<                 if (\function_exists('hash_equals')) {
<                     return \hash_equals($signature, $hash);
<                 }
<                 $len = \min(static::safeStrlen($signature), static::safeStrlen($hash));
< 
<                 $status = 0;
<                 for ($i = 0; $i < $len; $i++) {
<                     $status |= (\ord($signature[$i]) ^ \ord($hash[$i]));



>                 if (!\is_string($keyMaterial)) {
>                     throw new InvalidArgumentException('key must be a string when using hmac');



<                 $status |= (static::safeStrlen($signature) ^ static::safeStrlen($hash));
< 
<                 return ($status === 0);



>                 $hash = \hash_hmac($algorithm, $msg, $keyMaterial, true);
>                 return self::constantTimeEquals($hash, $signature);



<      * @return object Object representation of JSON string



>      * @return mixed The decoded JSON string



<     public static function jsonDecode($input)



>     public static function jsonDecode(string $input)



<         if (\version_compare(PHP_VERSION, '5.4.0', '>=') && !(\defined('JSON_C_VERSION') && PHP_INT_SIZE > 4)) {
<             /** In PHP >=5.4.0, json_decode() accepts an options parameter, that allows you
<              * to specify that large ints (like Steam Transaction IDs) should be treated as
<              * strings, rather than the PHP default behaviour of converting them to floats.
<              */



<         } else {
<             /** Not all servers will support that, however, so for older versions we must
<              * manually detect large ints in the JSON string and quote them (thus converting
<              *them to strings) before decoding, hence the preg_replace() call.
<              */
<             $max_int_length = \strlen((string) PHP_INT_MAX) - 1;
<             $json_without_bigints = \preg_replace('/:\s*(-?\d{'.$max_int_length.',})/', ': "$1"', $input);
<             $obj = \json_decode($json_without_bigints);
<         }



<             static::handleJsonError($errno);



>             self::handleJsonError($errno);


        }
        return $obj;
    }

    /**

<      * Encode a PHP object into a JSON string.



>      * Encode a PHP array into a JSON string.


     *

<      * @param object|array $input A PHP object or array



>      * @param array<mixed> $input A PHP array


     *

<      * @return string JSON representation of the PHP object or array



>      * @return string JSON representation of the PHP array


     *
     * @throws DomainException Provided object could not be encoded to valid JSON
     */

<     public static function jsonEncode($input)



>     public static function jsonEncode(array $input): string


    {

>         if (PHP_VERSION_ID >= 50400) {
        $json = \json_encode($input);
>             $json = \json_encode($input, \JSON_UNESCAPED_SLASHES);
        if ($errno = \json_last_error()) {
>         } else {
            static::handleJsonError($errno);
>             // PHP 5.3 only


        } elseif ($json === 'null' && $input !== null) {

>         }



<             static::handleJsonError($errno);



>             self::handleJsonError($errno);


        }

>         if ($json === false) {
        return $json;
>             throw new DomainException('Provided object could not be encoded to valid JSON');
    }
>         }



    /**
     * Decode a string with URL-safe Base64.
     *
     * @param string $input A Base64 encoded string
     *
     * @return string A decoded string

>      *
     */
>      * @throws InvalidArgumentException invalid base64 characters



<     public static function urlsafeB64Decode($input)



>     public static function urlsafeB64Decode(string $input): string


    {
        $remainder = \strlen($input) % 4;
        if ($remainder) {
            $padlen = 4 - $remainder;
            $input .= \str_repeat('=', $padlen);
        }
        return \base64_decode(\strtr($input, '-_', '+/'));
    }

    /**
     * Encode a string with URL-safe Base64.
     *
     * @param string $input The string you want encoded
     *
     * @return string The base64 encode of what you passed in
     */

<     public static function urlsafeB64Encode($input)



>     public static function urlsafeB64Encode(string $input): string


    {
        return \str_replace('=', '', \strtr(\base64_encode($input), '+/', '-_'));
    }


> 
    /**
>     /**
     * Helper method to create a JSON error.
>      * Determine if an algorithm has been provided for each Key
     *
>      *
     * @param int $errno An error number from json_last_error()
>      * @param Key|ArrayAccess<string,Key>|array<string,Key> $keyOrKeyArray
     *
>      * @param string|null            $kid
     * @return void
>      *
     */
>      * @throws UnexpectedValueException
    private static function handleJsonError($errno)
>      *
    {
>      * @return Key
        $messages = array(
>      */
            JSON_ERROR_DEPTH => 'Maximum stack depth exceeded',
>     private static function getKey(
            JSON_ERROR_STATE_MISMATCH => 'Invalid or malformed JSON',
>         $keyOrKeyArray,
            JSON_ERROR_CTRL_CHAR => 'Unexpected control character found',
>         ?string $kid
            JSON_ERROR_SYNTAX => 'Syntax error, malformed JSON',
>     ): Key {
            JSON_ERROR_UTF8 => 'Malformed UTF-8 characters' //PHP >= 5.3.3
>         if ($keyOrKeyArray instanceof Key) {
        );
>             return $keyOrKeyArray;
        throw new DomainException(
>         }
            isset($messages[$errno])
> 
            ? $messages[$errno]
>         if (empty($kid)) {
            : 'Unknown JSON error: ' . $errno
>             throw new UnexpectedValueException('"kid" empty, unable to lookup correct key');
        );
>         }
    }
> 

>         if ($keyOrKeyArray instanceof CachedKeySet) {
    /**
>             // Skip "isset" check, as this will automatically refresh if not set
     * Get the number of bytes in cryptographic strings.
>             return $keyOrKeyArray[$kid];
     *
>         }
     * @param string $str
> 
     *
>         if (!isset($keyOrKeyArray[$kid])) {
     * @return int
>             throw new UnexpectedValueException('"kid" invalid, unable to lookup correct key');
     */
>         }
    private static function safeStrlen($str)
> 
    {
>         return $keyOrKeyArray[$kid];
        if (\function_exists('mb_strlen')) {
>     }
            return \mb_strlen($str, '8bit');
> 
        }
>     /**
        return \strlen($str);
>      * @param string $left  The string of known length to compare against
    }
>      * @param string $right The user-supplied string

>      * @return bool
    /**
>      */
     * Convert an ECDSA signature to an ASN.1 DER sequence
>     public static function constantTimeEquals(string $left, string $right): bool
     *
>     {
     * @param   string $sig The ECDSA signature to convert
>         if (\function_exists('hash_equals')) {
     * @return  string The encoded DER object
>             return \hash_equals($left, $right);
     */
>         }
    private static function signatureToDER($sig)
>         $len = \min(self::safeStrlen($left), self::safeStrlen($right));
    {
> 
        // Separate the signature into r-value and s-value
>         $status = 0;
        list($r, $s) = \str_split($sig, (int) (\strlen($sig) / 2));
>         for ($i = 0; $i < $len; $i++) {

>             $status |= (\ord($left[$i]) ^ \ord($right[$i]));
        // Trim leading zeros
>         }
        $r = \ltrim($r, "\x00");
>         $status |= (self::safeStrlen($left) ^ self::safeStrlen($right));
        $s = \ltrim($s, "\x00");
> 

>         return ($status === 0);
        // Convert r-value and s-value from unsigned big-endian integers to
>     }
        // signed two's complement
> 


        if (\ord($r[0]) > 0x7f) {

>      * @throws DomainException
            $r = "\x00" . $r;
>      *



<     private static function handleJsonError($errno)



>     private static function handleJsonError(int $errno): void



<         $messages = array(



>         $messages = [



<         );



>         ];



<     private static function safeStrlen($str)



>     private static function safeStrlen(string $str): int



<     private static function signatureToDER($sig)



>     private static function signatureToDER(string $sig): string



<         list($r, $s) = \str_split($sig, (int) (\strlen($sig) / 2));



>         $length = max(1, (int) (\strlen($sig) / 2));
>         list($r, $s) = \str_split($sig, $length);


            self::ASN1_SEQUENCE,
            self::encodeDER(self::ASN1_INTEGER, $r) .
            self::encodeDER(self::ASN1_INTEGER, $s)
        );
    }

    /**
     * Encodes a value into a DER object.
     *
     * @param   int     $type DER tag
     * @param   string  $value the value to encode

>      *


     * @return  string  the encoded object
     */

<     private static function encodeDER($type, $value)



>     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 signature from a DER object.
     *
     * @param   string  $der binary signature in DER format
     * @param   int     $keySize the number of bits in the key

>      *


     * @return  string  the signature
     */

<     private static function signatureFromDER($der, $keySize)



>     private static function signatureFromDER(string $der, int $keySize): string


    {
        // OpenSSL returns the ECDSA signatures as a binary ASN.1 DER SEQUENCE
        list($offset, $_) = self::readDER($der);
        list($offset, $r) = self::readDER($der, $offset);
        list($offset, $s) = self::readDER($der, $offset);

        // Convert r-value and s-value from signed two's compliment to unsigned
        // big-endian integers
        $r = \ltrim($r, "\x00");
        $s = \ltrim($s, "\x00");

        // Pad out r and s so that they are $keySize bits long
        $r = \str_pad($r, $keySize / 8, "\x00", STR_PAD_LEFT);
        $s = \str_pad($s, $keySize / 8, "\x00", STR_PAD_LEFT);

        return $r . $s;
    }

    /**
     * Reads binary DER-encoded data and decodes into a single object
     *
     * @param string $der the binary data in DER format
     * @param int $offset the offset of the data stream containing the object
     * to decode

<      * @return array [$offset, $data] the new offset and the decoded object



>      *
>      * @return array{int, string|null} the new offset and the decoded object


     */

<     private static function readDER($der, $offset = 0)



>     private static function readDER(string $der, int $offset = 0): array


    {
        $pos = $offset;
        $size = \strlen($der);
        $constructed = (\ord($der[$pos]) >> 5) & 0x01;
        $type = \ord($der[$pos++]) & 0x1f;

        // Length
        $len = \ord($der[$pos++]);
        if ($len & 0x80) {
            $n = $len & 0x1f;
            $len = 0;
            while ($n-- && $pos < $size) {
                $len = ($len << 8) | \ord($der[$pos++]);
            }
        }

        // Value

<         if ($type == self::ASN1_BIT_STRING) {



>         if ($type === self::ASN1_BIT_STRING) {


            $pos++; // Skip the first contents octet (padding indicator)
            $data = \substr($der, $pos, $len - 1);
            $pos += $len - 1;
        } elseif (!$constructed) {
            $data = \substr($der, $pos, $len);
            $pos += $len;
        } else {
            $data = null;
        }


<         return array($pos, $data);



>         return [$pos, $data];


    }
}