There's no DRM with the current Flash iteration either. They use blowfish to obfuscate the audio URLs in the XML playlists, but the audio files themselves are standard unencrypted AAC/MP3 downloaded over HTTP.
The blowfish keys are easily grabbed after an update, it is off course a cat and mouse game, but overall pianobar and other stand-alone clients seem to be doing fairly well at keeping up.
I don't listen to music using the flash interface anymore, the biggest problem is that after just an hour or two of listening the flash application is using a HUGE amount of memory and is hogging one of my cores at 90%. Flash on Mac OS X was never anything to write home about ...
