New Feature: Support AES-GCM (#5)

* feat: 🎸 Implement encryption with HMAC signature verification * fix: 🐛 Wrong namespace in tests * test: 💍 Test new feature * Revert "feat: 🎸 Implement encryption with HMAC signature verification" This reverts commit e615000. * Revert "test: 💍 Test new feature" This reverts commit 01dd73a. * feat: 🎸 Support AES-GCM Method * fix: 🐛 Move core logic from decrypt() to mustDecrypt() For providing more details * test: 💍 Add detailed tests * fix: 🐛 Don't pass $tag argument withoug GCM
mpyw · Jun 29, 2021 · c33cd8f · c33cd8f
1 parent bd175dc
commit c33cd8f
Show file tree

Hide file tree

Showing 3 changed files with 143 additions and 20 deletions.
diff --git a/src/Cryptor.php b/src/Cryptor.php
@@ -18,7 +18,12 @@ class Cryptor implements CryptorInterface
     /**
      * @var int
      */
-    protected $length;
+    protected $ivLength;
+
+    /**
+     * @var null|int
+     */
+    protected $tagLength;
 
     /**
      * Constructor.
@@ -34,7 +39,13 @@ public function __construct(string $method = self::DEFAULT_CIPHER_METHOD)
         }
 
         $this->method = $method;
-        $this->length = openssl_cipher_iv_length($method);
+        $this->ivLength = openssl_cipher_iv_length($method);
+
+        set_error_handler(function () {});
+        openssl_encrypt('', $this->method, '', OPENSSL_RAW_DATA, $this->random($this->ivLength), $tag);
+        restore_error_handler();
+
+        $this->tagLength = $tag === null ? null : strlen($tag);
     }
 
     /**
@@ -46,16 +57,19 @@ public function __construct(string $method = self::DEFAULT_CIPHER_METHOD)
      */
     public function encrypt(string $data, string $password): string
     {
-        $iv = $this->random($this->length);
-        $encrypted = openssl_encrypt($data, $this->method, $password, OPENSSL_RAW_DATA, $iv);
+        $iv = $this->random($this->ivLength);
+        $tag = null;
+        $encrypted = $this->tagLength
+            ? openssl_encrypt($data, $this->method, $password, OPENSSL_RAW_DATA, $iv, $tag)
+            : openssl_encrypt($data, $this->method, $password, OPENSSL_RAW_DATA, $iv);
 
         if ($encrypted === false) {
             // @codeCoverageIgnoreStart
             throw new EncryptionFailedException(openssl_error_string());
             // @codeCoverageIgnoreEnd
         }
 
-        return "$iv$encrypted";
+        return "$iv$encrypted$tag";
     }
 
     /**
@@ -67,14 +81,11 @@ public function encrypt(string $data, string $password): string
      */
     public function decrypt(string $data, string $password)
     {
-        $iv = substr($data, 0, $this->length);
-
-        if (strlen($iv) !== $this->length) {
+        try {
+            return $this->mustDecrypt($data, $password);
+        } catch (DecryptionFailedException $e) {
             return false;
         }
-
-        $data = substr($data, $this->length);
-        return openssl_decrypt($data, $this->method, $password, OPENSSL_RAW_DATA, $iv);
     }
 
     /**
@@ -87,10 +98,35 @@ public function decrypt(string $data, string $password)
      */
     public function mustDecrypt(string $data, string $password): string
     {
-        $decrypted = $this->decrypt($data, $password);
+        $originalData = $data;
+
+        $iv = substr($data, 0, $this->ivLength);
+        if (strlen($iv) !== $this->ivLength) {
+            throw new DecryptionFailedException('invalid iv length.', $originalData);
+        }
+        $data = substr($data, $this->ivLength);
+
+        $tag = null;
+        if ($this->tagLength !== null) {
+            $tag = substr($data, -$this->tagLength);
+            if (strlen($tag) !== $this->tagLength) {
+                throw new DecryptionFailedException('invalid tag length.', $originalData);
+            }
+            $data = substr($data, 0, -$this->tagLength);
+        }
+
+        $decrypted = $this->tagLength
+            ? openssl_decrypt($data, $this->method, $password, OPENSSL_RAW_DATA, $iv, $tag)
+            : openssl_decrypt($data, $this->method, $password, OPENSSL_RAW_DATA, $iv);
 
         if ($decrypted === false) {
-            throw new DecryptionFailedException(openssl_error_string(), $data);
+            $error = openssl_error_string();
+            if ($error === false) {
+                $error = $this->tagLength
+                    ? 'invalid tag content.'
+                    : 'unknown error.';
+            }
+            throw new DecryptionFailedException($error, $originalData);
         }
 
         return $decrypted;

diff --git a/tests/CryptorTest.php b/tests/CryptorTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Tests;
+namespace Mpyw\EasyCrypt\Tests;
 
 use Mpyw\EasyCrypt\Cryptor;
 use Mpyw\EasyCrypt\Exceptions\DecryptionFailedException;
@@ -32,6 +32,20 @@ public function testAes256(): void
         $this->assertFalse($cryptor->decrypt($encryptedA, 'passward'));
     }
 
+    public function testAes256Gcm(): void
+    {
+        $cryptor = new Cryptor('aes-256-gcm');
+
+        $encryptedA = $cryptor->encrypt('data', 'password');
+        $encryptedB = $cryptor->encrypt('data', 'password');
+
+        $this->assertSame('data', $cryptor->decrypt($encryptedA, 'password'));
+        $this->assertSame('data', $cryptor->decrypt($encryptedB, 'password'));
+        $this->assertNotSame($encryptedA, $encryptedB);
+
+        $this->assertFalse($cryptor->decrypt($encryptedA, 'passward'));
+    }
+
     public function testRc4(): void
     {
         $cryptor = new Cryptor('rc4');
@@ -46,7 +60,7 @@ public function testRc4(): void
         $this->assertNotFalse($cryptor->decrypt($encryptedA, 'passward'));
     }
 
-    public function testInvalidIv(): void
+    public function testInvalidIvLength(): void
     {
         $cryptor = new Cryptor();
         $this->assertFalse($cryptor->decrypt('', 'password'));
@@ -57,7 +71,44 @@ public function testInvalidIv(): void
         } catch (DecryptionFailedException $e) {
             $this->assertSame('', $e->getData());
             $this->assertSame('Failed to decrypt.', $e->getMessage());
-            $this->assertSame('error:06065064:digital envelope routines:EVP_DecryptFinal_ex:bad decrypt', $e->getOriginalMessage());
+            $this->assertSame('invalid iv length.', $e->getOriginalMessage());
+        }
+    }
+
+    public function testInvalidTagLength(): void
+    {
+        $cryptor = new Cryptor('aes-256-gcm');
+        $this->assertFalse($cryptor->decrypt(str_repeat('x', 16), 'password'));
+
+        try {
+            $cryptor->mustDecrypt(str_repeat('x', 16), 'password');
+            $this->assertTrue(false);
+        } catch (DecryptionFailedException $e) {
+            $this->assertSame(str_repeat('x', 16), $e->getData());
+            $this->assertSame('Failed to decrypt.', $e->getMessage());
+            $this->assertSame('invalid tag length.', $e->getOriginalMessage());
+        }
+    }
+
+    public function testInvalidTagContent(): void
+    {
+        $cryptor = new Cryptor('aes-256-gcm');
+
+        $corrupted = substr_replace(
+            $cryptor->encrypt('', 'password'),
+            str_repeat('x', 16),
+            -16
+        );
+
+        $this->assertFalse($cryptor->decrypt($corrupted, 'password'));
+
+        try {
+            $cryptor->mustDecrypt($corrupted, 'password');
+            $this->assertTrue(false);
+        } catch (DecryptionFailedException $e) {
+            $this->assertSame($corrupted, $e->getData());
+            $this->assertSame('Failed to decrypt.', $e->getMessage());
+            $this->assertSame('invalid tag content.', $e->getOriginalMessage());
         }
     }
 }
diff --git a/tests/FixedPasswordCryptorTest.php b/tests/FixedPasswordCryptorTest.php
@@ -1,10 +1,9 @@
 <?php
 
-namespace Tests;
+namespace Mpyw\EasyCrypt\Tests;
 
 use Mpyw\EasyCrypt\Cryptor;
 use Mpyw\EasyCrypt\Exceptions\DecryptionFailedException;
-use Mpyw\EasyCrypt\Exceptions\UnsupportedCipherException;
 use Mpyw\EasyCrypt\FixedPasswordCryptor;
 use PHPUnit\Framework\TestCase;
 
@@ -43,7 +42,7 @@ public function testRc4(): void
         $this->assertNotFalse($anotherCryptor->decrypt($encryptedA));
     }
 
-    public function testInvalidIv(): void
+    public function testInvalidIvLength(): void
     {
         $cryptor = new FixedPasswordCryptor('password');
         $this->assertFalse($cryptor->decrypt(''));
@@ -54,7 +53,44 @@ public function testInvalidIv(): void
         } catch (DecryptionFailedException $e) {
             $this->assertSame('', $e->getData());
             $this->assertSame('Failed to decrypt.', $e->getMessage());
-            $this->assertSame('error:06065064:digital envelope routines:EVP_DecryptFinal_ex:bad decrypt', $e->getOriginalMessage());
+            $this->assertSame('invalid iv length.', $e->getOriginalMessage());
+        }
+    }
+
+    public function testInvalidTagLength(): void
+    {
+        $cryptor = new FixedPasswordCryptor('password', new Cryptor('aes-256-gcm'));
+        $this->assertFalse($cryptor->decrypt(str_repeat('x', 16)));
+
+        try {
+            $cryptor->mustDecrypt(str_repeat('x', 16));
+            $this->assertTrue(false);
+        } catch (DecryptionFailedException $e) {
+            $this->assertSame(str_repeat('x', 16), $e->getData());
+            $this->assertSame('Failed to decrypt.', $e->getMessage());
+            $this->assertSame('invalid tag length.', $e->getOriginalMessage());
+        }
+    }
+
+    public function testInvalidTagContent(): void
+    {
+        $cryptor = new FixedPasswordCryptor('password', new Cryptor('aes-256-gcm'));
+
+        $corrupted = substr_replace(
+            $cryptor->encrypt(''),
+            str_repeat('x', 16),
+            -16
+        );
+
+        $this->assertFalse($cryptor->decrypt($corrupted));
+
+        try {
+            $cryptor->mustDecrypt($corrupted);
+            $this->assertTrue(false);
+        } catch (DecryptionFailedException $e) {
+            $this->assertSame($corrupted, $e->getData());
+            $this->assertSame('Failed to decrypt.', $e->getMessage());
+            $this->assertSame('invalid tag content.', $e->getOriginalMessage());
         }
     }
 }