From 413741fa84e6874aa88a1ae6029adf4060e89374 Mon Sep 17 00:00:00 2001
From: Stephen Paul Weber <singpolyma@singpolyma.net>
Date: Wed, 25 Jul 2018 09:56:57 -0500
Subject: [PATCH] Throw more helpful exception when already decrypted

---
 lib/openpgp_crypt_symmetric.php | 3 +++
 tests/phpseclib_suite.php       | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/lib/openpgp_crypt_symmetric.php b/lib/openpgp_crypt_symmetric.php
index 844c53b..c853379 100644
--- a/lib/openpgp_crypt_symmetric.php
+++ b/lib/openpgp_crypt_symmetric.php
@@ -146,6 +146,9 @@ class OpenPGP_Crypt_Symmetric {
   public static function getCipher($algo) {
     $cipher = NULL;
     switch($algo) {
+		case NULL:
+		case 0:
+			throw new Exception("Data is already unencrypted");
       case 2:
           $cipher = new Crypt_TripleDES(CRYPT_DES_MODE_CFB);
           $key_bytes = 24;
diff --git a/tests/phpseclib_suite.php b/tests/phpseclib_suite.php
index 0f6ae30..6e7f2e5 100644
--- a/tests/phpseclib_suite.php
+++ b/tests/phpseclib_suite.php
@@ -114,6 +114,13 @@ class Decryption extends PHPUnit_Framework_TestCase {
     $skey = OpenPGP_Crypt_Symmetric::decryptSecretKey("hello", $key[0]);
     $this->assertSame(!!$skey, true);
   }
+
+  public function testAlreadyDecryptedSecretKey() {
+    $this->expectException(Exception::class);
+    $this->expectExceptionMessage("Data is already unencrypted");
+    $key = OpenPGP_Message::parse(file_get_contents(dirname(__FILE__) . '/data/helloKey.gpg'));
+    OpenPGP_Crypt_Symmetric::decryptSecretKey("hello", $key[0]);
+  }
 }
 
 class Encryption extends PHPUnit_Framework_TestCase {