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hedera-web-mindshore/web/jwt.php

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2.1 KiB
PHP

<?php
namespace Vn\Web;
use Exception;
/**
* Basic class to encode, decode and verify JWT tokens. It implements the HS256
* algorithm from the RFC 7519 standard.
**/
class Jwt
{
/**
* Creates a new JWT token with the passed $payload and $key.
*
* @param {Array} $payload The data to encode
* @param {string} $key The key used to sign the token
* @return {string} The new JWT token
**/
static function encode ($payload, $key)
{
$header = [
'alg' => 'HS256',
'typ' => 'JWT'
];
$b64Header = self::jsonB64Encode ($header);
$b64Payload = self::jsonB64Encode ($payload);
$b64Signature = self::getSignature ($b64Header, $b64Payload, $key);
return "$b64Header.$b64Payload.$b64Signature";
}
/**
* Validates and extracts the data from a JWT token.
*
* @param {Array} $token The JWT token
* @param {string} $key The key used to validate the token
* @return {string} The JWT validated and decoded data
**/
static function decode ($token, $key)
{
$parts = explode ('.', $token);
if (count($parts) !== 3)
throw new Exception ('Bad JWT token');
$b64Header = $parts[0];
$b64Payload = $parts[1];
$b64Signature = $parts[2];
$header = self::jsonB64Decode ($b64Header);
$payload = self::jsonB64Decode ($b64Payload);
if ($b64Signature != self::getSignature ($b64Header, $b64Payload, $key))
throw new Exception ('Bad token signature');
return $payload;
}
static function getSignature ($b64Header, $b64Payload, $key)
{
$signature = hash_hmac ('sha256', "$b64Header.$b64Payload", $key, TRUE);
return self::base64UrlEncode ($signature);
}
static function jsonB64Encode ($data)
{
return self::base64UrlEncode (json_encode ($data));
}
static function jsonB64Decode ($data)
{
return json_decode (self::base64UrlDecode ($data), TRUE);
}
static function base64UrlEncode ($data)
{
return rtrim (strtr (base64_encode ($data), '+/', '-_'), '=');
}
static function base64UrlDecode ($data)
{
$remainder = strlen ($data) % 4;
$data = strtr ($data, '-_', '+/');
return base64_decode (str_pad ($data, $remainder, '=', STR_PAD_RIGHT));
}
}