add rethrow option

index.js

@@ -177,9 +177,10 @@ function encrypt_aes (text, pass) {
  *
  * @param {string} ciphertext encrypted text
  * @param {string} pass password
+ * @param {boolean} rethrow rethrow exceptions instead of returning null
  * @returns {string} plaintext
  */
-function decrypt_aes (ciphertext, pass) {
+function decrypt_aes (ciphertext, pass, rethrow = false) {
   try {
     let buf = Buffer.from (ciphertext, 'base64');
     const salt = buf.slice (0, encryption.salt_size);
@@ -202,8 +203,10 @@ function decrypt_aes (ciphertext, pass) {
       .toString ('utf-8');
   }
   catch (e) {
-    return null;
+    if (rethrow)
+      throw e;
   }
+  return null;
 }
 
 module.exports = {

test/encryption.js

@@ -22,6 +22,13 @@ test ('fail decryption', (t) => {
   t.is (dec, null);
 });
 
+test ('rethrow decryption', (t) => {
+  const enc = crypto.encrypt_aes ('foo', 'bar');
+  t.throws (() => {
+    const dec = crypto.decrypt_aes (enc, 'baz', true);
+  });
+});
+
 test ('unique crypto strings', (t) => {
   const enc = [
     crypto.encrypt_aes ('foo', 'bar'),