Scoped Keys Issue - keen-js

keen-js-scoped-keys.js

> Keen = require('keen-js');
> Keen.version
'3.4.0-rc4'
> var masterKey = process.env.YAPP_KEEN_MASTER_KEY;
> var appIdA = 'xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx';
> var scopedKeyA = Keen.utils.encryptScopedKey(masterKey, {
...   filters: [{
.....     property_name: 'appId',
.....     operator: 'eq',
.....     property_value: appIdA
.....   }]
... });
Error: Invalid key length
    at Error (native)
    at new Cipheriv (crypto.js:225:16)
    at Object.Cipheriv (crypto.js:223:12)
    at Object.module.exports [as encryptScopedKey] (/xxxxx/xxxxxxxxxxxxx/x/xxxxxxx/xxxxxxxx/xxxx-xxxxxx/xxxxxxxxxxxx/xxxx-xx/xxx/xxxxxx/xxxxx/xxxxxxxxxxxxxxxx.xx:x:xx)
    at repl:1:29
    at REPLServer.defaultEval (repl.js:132:27)
    at bound (domain.js:254:14)
    at REPLServer.runBound [as eval] (domain.js:267:12)
    at REPLServer.<anonymous> (repl.js:279:12)
    at REPLServer.emit (events.js:107:17)