(dev/core#2258) CryptoToken - Change notation

This is pre-merge change to the notation in the token. Two things: * Use only one control character instead of multiple. * Use URL-style key-value notation. It should be easier to skim and to tweak.
civicrm · Dec 19, 2020 · 5b394c8 · 5b394c8
1 parent 4228925
commit 5b394c8
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Showing 2 changed files with 36 additions and 18 deletions.
diff --git a/Civi/Crypto/CryptoToken.php b/Civi/Crypto/CryptoToken.php
@@ -34,17 +34,25 @@
  *
  *   - Plain text: Any string which does not begin with chr(2)
  *   - Encrypted text: A string in the format:
- *        TOKEN := DLM + VERSION + DLM + KEY_ID + DLM + CIPHERTEXT
- *        DLM := ASCII CHAR #2
- *        VERSION := String, 4-digit, alphanumeric (as in "CTK0")
- *        KEY_ID := String, alphanumeric and symbols "_-.,:;=+/\"
+ *        TOKEN := DLM + FMT + QUERY
+ *        DLM := ASCII char #2
+ *        FMT := String, 4-digit, alphanumeric (as in "CTK?")
+ *        QUERY := String, URL-encoded key-value pairs,
+ *           "k", the key ID (alphanumeric and symbols "_-.,:;=+/\")
+ *           "t", the text (base64-encoded ciphertext)
  *
  * @package Civi\Crypto
  */
 class CryptoToken {
 
-  const VERSION_1 = 'CTK0';
+  /**
+   * Format identification code
+   */
+  const FMT_QUERY = 'CTK?';
 
+  /**
+   * @var string
+   */
   protected $delim;
 
   /**
@@ -90,7 +98,11 @@ public function encrypt($plainText, $keyIdOrTag) {
     /** @var \Civi\Crypto\CipherSuiteInterface $cipherSuite */
     $cipherSuite = $registry->findSuite($key['suite']);
     $cipherText = $cipherSuite->encrypt($plainText, $key);
-    return $this->delim . self::VERSION_1 . $this->delim . $key['id'] . $this->delim . base64_encode($cipherText);
+
+    return $this->delim . self::FMT_QUERY . \http_build_query([
+      'k' => $key['id'],
+      't' => \CRM_Utils_String::base64UrlEncode($cipherText),
+    ]);
   }
 
   /**
@@ -118,16 +130,21 @@ public function decrypt($token, $keyIdOrTag = '*') {
     /** @var CryptoRegistry $registry */
     $registry = \Civi::service('crypto.registry');
 
-    $parts = explode($this->delim, $token, 4);
-    if (count($parts) !== 4 || $parts[1] !== self::VERSION_1) {
-      throw new CryptoException("Cannot decrypt token. Invalid format.");
+    $fmt = substr($token, 1, 4);
+    switch ($fmt) {
+      case self::FMT_QUERY:
+        parse_str(substr($token, 5), $tokenData);
+        $keyId = $tokenData['k'];
+        $cipherText = \CRM_Utils_String::base64UrlDecode($tokenData['t']);
+        break;
+
+      default:
+        throw new CryptoException("Cannot decrypt token. Invalid format.");
     }
-    $keyId = $parts[2];
-    $cipherText = base64_decode($parts[3]);
 
     $key = $registry->findKey($keyId);
     if (!in_array('*', $keyIdOrTag) && !in_array($keyId, $keyIdOrTag) && empty(array_intersect($keyIdOrTag, $key['tags']))) {
-      throw new CryptoException("Cannot decrypt token. Unexpected key: $keyId");
+      throw new CryptoException("Cannot decrypt token. Unexpected key: {$keyId}");
     }
 
     /** @var \Civi\Crypto\CipherSuiteInterface $cipherSuite */

diff --git a/tests/phpunit/Civi/Crypto/CryptoTokenTest.php b/tests/phpunit/Civi/Crypto/CryptoTokenTest.php
@@ -51,7 +51,8 @@ public function testDecryptInvalid() {
     $this->assertEquals('mess with me', $cryptoToken->decrypt($goodExample));
 
     try {
-      $badExample = preg_replace(';CTK0;', 'ctk9', $goodExample);
+      $badExample = preg_replace(';CTK\?;', 'ctk9', $goodExample);
+      $this->assertTrue($badExample !== $goodExample);
       $cryptoToken->decrypt($badExample);
       $this->fail("Expected CryptoException");
     }
@@ -64,11 +65,11 @@ public function getExampleTokens() {
     return [
       // [ 'Plain text', 'Encryption Key ID', 'expectTokenRegex', 'expectTokenLen', 'expectPlain' ]
       ['hello world. can you see me', 'plain', '/^hello world. can you see me/', 27, TRUE],
-      ['hello world. i am secret.', 'UNIT-TEST', '/^.CTK0.asdf-key-1./', 81, FALSE],
-      ['hello world. we b secret.', 'asdf-key-0', '/^.CTK0.asdf-key-0./', 81, FALSE],
-      ['hello world. u ur secret.', 'asdf-key-1', '/^.CTK0.asdf-key-1./', 81, FALSE],
-      ['hello world. he z secret.', 'asdf-key-2', '/^.CTK0.asdf-key-2./', 73, FALSE],
-      ['hello world. whos secret.', 'asdf-key-3', '/^.CTK0.asdf-key-3./', 125, FALSE],
+      ['hello world. i am secret.', 'UNIT-TEST', '/^.CTK\?k=asdf-key-1&/', 84, FALSE],
+      ['hello world. we b secret.', 'asdf-key-0', '/^.CTK\?k=asdf-key-0&/', 84, FALSE],
+      ['hello world. u ur secret.', 'asdf-key-1', '/^.CTK\?k=asdf-key-1&/', 84, FALSE],
+      ['hello world. he z secret.', 'asdf-key-2', '/^.CTK\?k=asdf-key-2&/', 75, FALSE],
+      ['hello world. whos secret.', 'asdf-key-3', '/^.CTK\?k=asdf-key-3&/', 127, FALSE],
     ];
   }