Merge pull request #6 from cleverage/bugfix/fix-blank-decryption

Fix a bug when decrypting blank string

Author: johnkrovitch

src/Encryption/AbstractEncryptionAdapter.php

@@ -69,7 +69,7 @@ public function generateKey(): string
     public function parseNonce(string &$message): string
     {
         if (mb_strlen($message, static::ENCODING) < $this->getNonceSize()) {
-            throw new BadNonceException('Unable to parse nounce from message');
+            throw new BadNonceException('Unable to parse nounce from message "'.$message.'"');
         }
         $nonce = mb_substr($message, 0, $this->getNonceSize(), static::ENCODING);
         $message = mb_substr($message, $this->getNonceSize(), null, static::ENCODING);

src/Manager/EncryptionManager.php

@@ -120,11 +120,15 @@ public function encryptString(string $string, string $nonce = null): string
      */
     public function decryptString(string $encryptedString, string $nonce = null): string
     {
-        if ($nonce === null) {
-            $nonce = $this->encryptionAdapter->parseNonce($encryptedString);
+        // Do not try to decrypt blank string
+        if ($encryptedString === '') {
+            return '';
         }
 
         try {
+            if ($nonce === null) {
+                $nonce = $this->encryptionAdapter->parseNonce($encryptedString);
+            }
             $decrypted = $this->encryptionAdapter->decrypt(
                 $encryptedString,
                 $nonce,
@@ -134,10 +138,10 @@ public function decryptString(string $encryptedString, string $nonce = null): st
             if ($this->throwExceptions) {
                 throw $exception;
             }
-    
+        
             return '';
         }
-
+    
         return rtrim($decrypted, "\0");
     }
 

tests/PHPUnit/Adapter/Aes256GcmSodiumEncryptionAdapterTest.php

@@ -37,6 +37,7 @@ public function getDataProvider(): array
             [bin2hex(random_bytes(400))],
             [bin2hex(random_bytes(1000))],
             [bin2hex(random_bytes(10000))],
+            [''],
         ];
     }