fixes

index.js

@@ -3,6 +3,7 @@
  * Created by Timo Hocker <timo@scode.ovh>, March 2020
  */
 
+// @ts-nocheck
 /* eslint-disable no-magic-numbers */
 'use strict';
 
@@ -13,7 +14,7 @@ const encryption = {
   algorithm:  'aes-256-gcm',
   nonce_size: 12,
   tag_size:   16,
-  key_size:   16,
+  key_size:   32,
   hash:       'sha256',
   salt_size:  16,
   iterations: 32767
@@ -181,8 +182,10 @@ function encrypt_aes (text, pass) {
  * @returns {string} plaintext
  */
 function decrypt_aes (ciphertext, pass) {
-  const buf = Buffer.from (ciphertext, 'base64');
+  try {
+    let buf = Buffer.from (ciphertext, 'base64');
     const salt = buf.slice (0, encryption.salt_size);
+    buf = buf.slice (encryption.salt_size);
     // eslint-disable-next-line no-sync
     const key = crypto.pbkdf2Sync (
       Buffer.from (pass, 'utf-8'),
@@ -191,24 +194,24 @@ function decrypt_aes (ciphertext, pass) {
       encryption.key_size,
       encryption.hash
     );
-  const nonce = buf.slice (encryption.salt_size, encryption.nonce_size);
-  const enc = buf.slice (
-    encryption.salt_size + encryption.nonce_size,
-    buf.length - encryption.salt_size - encryption.tag_size
-  );
+    const nonce = buf.slice (0, encryption.nonce_size);
+    buf = buf.slice (encryption.nonce_size);
     const tag = buf.slice (
-    encryption.salt_size
-    + encryption.nonce_size
-    + enc.length
+      buf.length - encryption.tag_size
     );
+    buf = buf.slice (0, buf.length - encryption.tag_size);
     const cipher = crypto.createDecipheriv (encryption.algorithm, key, nonce);
     cipher.setAuthTag (tag);
     return Buffer.concat ([
-    cipher.update (enc),
+      cipher.update (buf),
       cipher.final ()
     ])
       .toString ('utf-8');
   }
+  catch (e) {
+    return null;
+  }
+}
 
 module.exports = {
   checksum,

test/encryption.js

@@ -1,3 +1,5 @@
+/* eslint-disable no-magic-numbers */
+// @ts-nocheck
 'use strict';
 
 const test = require ('ava');
@@ -19,3 +21,18 @@ test ('fail decryption', (t) => {
   const dec = crypto.decrypt_aes (enc, 'baz');
   t.is (dec, null);
 });
+
+test ('unique crypto strings', (t) => {
+  const enc = [
+    crypto.encrypt_aes ('foo', 'bar'),
+    crypto.encrypt_aes ('foo', 'bar'),
+    crypto.encrypt_aes ('foo', 'bar'),
+    crypto.encrypt_aes ('foo', 'bar'),
+    crypto.encrypt_aes ('foo', 'bar'),
+    crypto.encrypt_aes ('foo', 'bar'),
+    crypto.encrypt_aes ('foo', 'bar'),
+    crypto.encrypt_aes ('foo', 'bar')
+  ];
+  const unique = enc.filter ((v, i) => enc.indexOf (v) === i).length;
+  t.is (unique, 8);
+});