"Replace mb_* functions with equivalent non-multibyte functions" (#578)

This commit replaces mb_* functions with non-multibyte equivalent functions, which don't require mbstring extension. It also adjusts the required PHP version in composer.json from 8.3 to 8.2. This change reduces dependencies and broadens compatibility without impacting functionality. It is part of an overall code simplification and optimization effort.

Author: Spomky

KeyEncryption/Chacha20Poly1305.php

@@ -13,6 +13,7 @@
 use RuntimeException;
 use function in_array;
 use function is_string;
+use function strlen;
 use const OPENSSL_RAW_DATA;
 
 final readonly class Chacha20Poly1305 implements KeyEncryption
@@ -68,7 +69,7 @@ public function decryptKey(JWK $key, string $encrypted_cek, array $header): stri
         isset($header['nonce']) || throw new InvalidArgumentException('The header parameter "nonce" is missing.');
         is_string($header['nonce']) || throw new InvalidArgumentException('The header parameter "nonce" is not valid.');
         $nonce = Base64UrlSafe::decodeNoPadding($header['nonce']);
-        if (mb_strlen($nonce, '8bit') !== 12) {
+        if (strlen($nonce) !== 12) {
             throw new InvalidArgumentException('The header parameter "nonce" is not valid.');
         }
 

Signature/Blake2b.php

@@ -13,13 +13,14 @@
 use function extension_loaded;
 use function in_array;
 use function is_string;
+use function strlen;
 
 /**
  * @see \Jose\Tests\Component\Signature\Algorithm\Blake2bTest
  */
 final readonly class Blake2b implements MacAlgorithm
 {
-    private const int MINIMUM_KEY_LENGTH = 32;
+    private const MINIMUM_KEY_LENGTH = 32;
 
     public function __construct()
     {
@@ -67,7 +68,7 @@ private function getKey(JWK $key): string
             throw new InvalidArgumentException('The key parameter "k" is invalid.');
         }
         $key = Base64UrlSafe::decodeNoPadding($k);
-        if (mb_strlen($key, '8bit') < self::MINIMUM_KEY_LENGTH) {
+        if (strlen($key) < self::MINIMUM_KEY_LENGTH) {
             throw new InvalidArgumentException('Key provided is shorter than 256 bits.');
         }
 

Signature/HS256_64.php

@@ -15,7 +15,7 @@ public function hash(JWK $key, string $input): string
     {
         $signature = parent::hash($key, $input);
 
-        return mb_substr($signature, 0, 8, '8bit');
+        return substr($signature, 0, 8);
     }
 
     #[Override]

composer.json

@@ -38,7 +38,7 @@
         }
     },
     "require": {
-        "php": ">=8.3",
+        "php": ">=8.2",
         "ext-openssl": "*",
         "web-token/jwt-library": "^4.0"
     }