Curious if anyone has read over this, and what their thoughts are. This is Microsoft's implementation of a proof-of-work system, similar to Hashcash (I hesitate to call it a "derivative"). http://msdn.microsoft.com/en-us/library/cc433493%28v=exchg.80%29.aspx From what I can tell, the protocol is covered by a royalty-based patent, which will prevent any Free Software implementations. What I find interesting, is the recipients, sender and subject are encoded into a base-64 string. What's the purpose of this? base-64 encoding doesn't add any significant time to the processing, and it's trivial to reverse getting the original data. Anyway, just curious. -- . o . o . o . . o o . . . o . . . o . o o o . o . o o . . o o o o . o . . o o o o . o o o