fix: setKey uses sha256 hash and encrypt method updated

README.md

@@ -33,8 +33,8 @@ use Dgcrypt\Dgcrypt;
 // Initialize the Dgcrypt class with the desired encryption method
 $dgcrypt = new Dgcrypt('aes-256-gcm'); // Can be 'aes-256-cbc', 'aes-256-gcm', or 'chacha20-poly1305'
 
-// Set a 32-character secret key
-$dgcrypt->setKey('your-32-character-long-key');
+// Set a secret key
+$dgcrypt->setKey('your-secret key');
 ```
 
 ### Encrypting Data on the Backend:
@@ -50,7 +50,7 @@ echo $encrypted;
 ### Decrypting Data on the Backend:
 ```php
 // Decrypt the previously encrypted string
-$decrypted = $dgcrypt->decrypt($encrypted);
+$decrypted = $dgcrypt->setCipherMethod('aes-256-cbc')->decrypt($encrypted);
 
 // Output the decrypted string
 echo $decrypted;
@@ -62,7 +62,7 @@ echo $decrypted;
 $generatedKey = $dgcrypt->generateKey();
 
 // Output the generated key
-echo bin2hex($generatedKey); // Display the key in hexadecimal format
+echo $generatedKey; // Display the hexadecimal key
 ```
 
 ### Setting the Initialization Vector (IV):

src/Dgcrypt.php

@@ -28,29 +28,26 @@ public function __construct(string $cipherMethod = 'aes-256-cbc')
     }
 
     /**
-     * Sets the secret key for encryption and decryption.
+     * Sets the secret key for encryption and decryption based on sha256 hash.
+     * Always 32 characters long.
      * 
-     * @param string $key The secret key (must be 32 characters)
+     * @param string $key
      * @return $this
-     * @throws \Exception if the key length is not 32 characters
      */
     public function setKey(string $key)
     {
-        if (strlen($key) !== 32) {
-            throw new \Exception('Secret key should be 32 characters');
-        }
-        $this->key = $key;
+        $this->key = substr(hash('sha256', $key),0,32);
         return $this;
     }
 
     /**
-     * Auto-generates a secure random key.
+     * Auto-generates a secure random key that is 32 characters long.
      * 
      * @return string The generated key
      */
     public function generateKey()
     {
-        $this->key = openssl_random_pseudo_bytes(32);
+        $this->setKey(openssl_random_pseudo_bytes(32));
         return $this->key;
     }
 
@@ -69,7 +66,7 @@ public function setIV(string $iv = null)
             $this->iv = openssl_random_pseudo_bytes($ivLength);
         } else {
             if (strlen($iv) !== $ivLength) {
-                throw new \Exception("IV should be $ivLength bytes");
+                throw new \Exception('IV length should be ' . $ivLength . ' bytes for ' . $this->cipherMethod);
             }
             $this->iv = $iv;
         }
@@ -102,7 +99,7 @@ public function setCipherMethod(string $method)
      * @return string The encrypted string, base64 encoded
      * @throws \Exception if the secret key is not defined or encryption fails
      */
-    public function encrypt(string $string, string $secretKey = null, bool $resetIV = false)
+    public function encrypt(string $string, string $secretKey = null, bool $resetIV = true)
     {
         if (!empty($secretKey)) {
             $this->setKey($secretKey);
@@ -142,15 +139,23 @@ public function encrypt(string $string, string $secretKey = null, bool $resetIV
         }
 
         if ($encryptedString === false) {
-            throw new \Exception('Encryption failed');
+            throw new \Exception('Encryption failed: ' . openssl_error_string());
+        }
+
+        // Base 64 encode the encrypted string
+        $encryptedString = base64_encode(bin2hex($encryptedString));
+        // Convert tag to hex
+        if (!empty($tag)) {
+            $tag = bin2hex($tag);
         }
 
+        // Add IV and tag to the encrypted string
+        $encryptedString = base64_encode(bin2hex($this->iv) . $tag . $encryptedString);
+
         if ($resetIV) {
             $this->iv = null;
         }
 
-        $encryptedString = base64_encode($this->iv . $tag . $encryptedString);
-
         return $encryptedString;
     }
 
@@ -169,7 +174,7 @@ public function decrypt(string $string, string $secretKey = null)
         } elseif (empty($this->key)) {
             throw new \Exception('Key for decrypting is not defined');
         }
-
+        // First Base64 decode the encrypted string
         $decodedString = base64_decode($string);
         if ($decodedString === false) {
             throw new \Exception('Encoded string is manipulated or corrupted');
@@ -178,11 +183,16 @@ public function decrypt(string $string, string $secretKey = null)
         $ivLength = openssl_cipher_iv_length($this->cipherMethod);
         $tagLength = ($this->cipherMethod === 'aes-256-gcm' || $this->cipherMethod === 'chacha20-poly1305') ? 16 : 0;
 
-        $tag=($tagLength > 0) ? substr($decodedString, $ivLength, $tagLength) : null;
-        $iv = substr($decodedString, 0, $ivLength);
-        $encryptedData = substr($decodedString, $ivLength + $tagLength);
+        // Extract IV and tag from the decoded string
+        $iv = hex2bin(substr($decodedString, 0, $ivLength * 2)); // hex string is twice the length of binary
+        $tag = ($tagLength > 0) ? hex2bin(substr($decodedString, $ivLength * 2, $tagLength * 2)) : null;
+
+        $encryptedData = substr($decodedString, ($ivLength + $tagLength) * 2);
 
-        switch($this->cipherMethod) {
+        // Second Base64 decode the encrypted data
+        $encryptedData = hex2bin(base64_decode($encryptedData));
+
+        switch ($this->cipherMethod) {
             case 'aes-256-cbc':
                 $decryptedString = openssl_decrypt(
                     $encryptedData,
@@ -207,7 +217,7 @@ public function decrypt(string $string, string $secretKey = null)
                 throw new \Exception('Unsupported cipher method');
         }
         if ($decryptedString === false) {
-            throw new \Exception('Decryption failed');
+            throw new \Exception('Decryption failed: ' . openssl_error_string());
         }
 
         return $decryptedString;

tests/DgcryptTest.php

@@ -100,9 +100,11 @@ public function testEncryptDecryptWithModifiedData()
         $encrypted = $dgcrypt->encrypt($this->originalText);
 
         // Modify encrypted data
-        $encrypted[10] = ($encrypted[10] === 'a') ? 'b' : 'a';
+        $decodedString = base64_decode($encrypted);
+        $decodedString[10] = ($decodedString[10] === 'a') ? 'b' : 'a';
+        $modifiedEncrypted = base64_encode($decodedString);
 
         $this->expectException(\Exception::class);
-        $dgcrypt->decrypt($encrypted);
+        $dgcrypt->decrypt($modifiedEncrypted);
     }
 }