There's a comment in the source code about b64: # If you don't like non-valid characters in the hostname, # then use hex encoding rather than base64 So far,

There's a comment in the source code about b64: # If you don't like non-valid characters in the hostname, # then use hex encoding rather than base64 So far, I've not encountered a failure using b64 encoding. But that could be an issue. And as you say, other encodings could be used if that does prove to be a problem.