Replace calls to deprecated crypto methods createCipher and createDec…

lib/simplecrypt.js

@@ -1,8 +1,60 @@
 // Simple module to encrypt / decrypt strings
+//
+// 2020-07-06 Patched to replace calls to deprecated crypto methods createCipher and createDecipher
+// with createCipheriv and createDecipheriv
+//
+// Changes based on gist from Ben Noordhuis <info@bnoordhuis.nl>
+// https://gist.github.com/bnoordhuis/2de2766d3d3a47ebe41aaaec7e8b14df
+//
+// Copyright (c) 2017, Ben Noordhuis <info@bnoordhuis.nl>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
 var crypto = require('crypto');
+
+function sizes(crypt_method) {
+  for (let nkey = 1, niv = 0;;) {
+    try {
+      crypto.createCipheriv(crypt_method, '.'.repeat(nkey), '.'.repeat(niv));
+      return [nkey, niv];
+    } catch (e) {
+      if (/invalid iv length/i.test(e.message)) niv += 1;
+      else if (/invalid key length/i.test(e.message)) nkey += 1;
+      else throw e;
+    }
+  }
+}
+
+function compute(crypt_method, passphrase) {
+  let [nkey, niv] = sizes(crypt_method);
+  for (let key = '', iv = '', p = '';;) {
+    const h = crypto.createHash('md5');
+    h.update(p, 'hex');
+    h.update(passphrase);
+    p = h.digest('hex');
+    let n, i = 0;
+    n = Math.min(p.length-i, 2*nkey);
+    nkey -= n/2, key += p.slice(i, i+n), i += n;
+    n = Math.min(p.length-i, 2*niv);
+    niv -= n/2, iv += p.slice(i, i+n), i += n;
+    if (nkey+niv === 0) return [key, iv];
+  }
+}
+
 module.exports = function(opts) {
   opts = opts || {};
 
+
   var CRYPT_METHOD = opts.method || 'aes192',
       PASS = opts.password || crypto.randomBytes(256),
       SALT = opts.salt || crypto.randomBytes(32).toString('hex'),
@@ -11,13 +63,20 @@ module.exports = function(opts) {
 
   return {
     encrypt: function (message) {
-      var cipher = crypto.createCipher(CRYPT_METHOD, PASS);
+      const [c_key, c_iv] = compute(CRYPT_METHOD, PASS);
+      const key  = Buffer.from(c_key, 'hex');
+      const iv  = Buffer.from(c_iv, 'hex');
+      const cipher = crypto.createCipheriv(CRYPT_METHOD, key, iv);
       var digest = cipher.update(message + SALT, encoding, digestEncoding);
       return digest + cipher.final(digestEncoding);
     },
 
     decrypt: function (digest) {
-      var decipher = crypto.createDecipher(CRYPT_METHOD, PASS);
+      const [c_key, c_iv] = compute(CRYPT_METHOD, PASS);
+      const key  = Buffer.from(c_key, 'hex');
+      const iv  = Buffer.from(c_iv, 'hex');
+      const decipher = crypto.createDecipheriv(CRYPT_METHOD, key, iv);
+
       var message = decipher.update(digest, digestEncoding, encoding);
       message = message + decipher.final(encoding);
       return message.substring(0, message.length - SALT.length);