Found an issue validating a PGP-signed update with latin1 encoding.

The application uses String.getBytes() to encode the signed content as byte[] before validation. However, extended latin1 characters (such as u-umlaut) are incorrectly encoded as multiple (UTF-8) bytes. This causes signed message validation to fail. 

The solution is to specify the original character set when encoding the content String into bytes (added a TODO).
Use a static character set, no need to lookup every time.