That problem got caused by the new version of the crypto-js module. Got already fixed. If you pull the latest code you will get the fix. Here is the commit:
https://github.com/n8n-io/n8n/commit/e67afb9e922bdaf12acb236987af1346b229c1c7
And the issue on Github:
https://github.com/n8n-io/n8n/issues/300