This seems clever, however, it will also take significant computational effort to verify the computational effort was actually done. Even if a class of functions are found that are "easier" to verify than to compute, they will no doubt still take up a significant fraction of time. Also, all outgoing messages would need this computation, since a mailserver does not know who it has sent mail to in the past, and whether they are still in receipt of the verification. So then you would only be able to send 8000 messages a day, too. Clearly, that doesn't scale very well. It seems unlikely that this would change the percentage of spam, since it would merely reduce the total amount of mail sent. I haven't observed a recent proliferation of spam, however. Spam seems to be level. --Dean On Fri, 6 Dec 2002, Ayyasamy, Senthilkumar (UMKC-Student) wrote: > this is the work all about (yesterday's seminar in a MIT group) > > " If I don't know you, and you want your e-mail to appear in my > inbox, then you must attach to your message an easily verified > "proof of computational effort", just for me and just for this > message. > > If the proof of effort requires, say, 10 seconds to compute, then the > economics of sending spam are radically altered, as a single machine > can send only 8,000 messages per day. > > The recent proliferation of spam has lead to a renewed interest in > these ideas. This work is about both the choice of > functions that can be used to yield easily verifiable proofs of > computational effort, and architectures for implementing the proof of > effort approach. Filtering and/or forcing senders to pay in other > currencies, such as human attention and money, will be covered as time > permits" > > > for more details http://research.microsoft.com/research/sv/PennyBlack > > > > -- > to unsubscribe send a message to namedroppers-request@ops.ietf.org with > the word 'unsubscribe' in a single line as the message text body. > archive: <http://ops.ietf.org/lists/namedroppers/> >