Citibank offers a "Virtual Account Number" service for their credit cards (Mastercard). It works fairly well. You can do one-shot purchases, or recurring purchases with the same merchant only, or even cap the total you're willing to spend via a virtual number over a number of months.
They have a web interface, but you can also download a Java applet that can generate numbers and fill in purchase forms for you.
In fact, SkyOne viewers only have 2 episodes left to watch from the first season. The first season order was for 13 episodes. Episode 12 is showing next Monday. Check out TV Tome.
Puzzles and CPU speeds
on
Spam, Milord
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· Score: 4, Interesting
Related to the discussion of crypto puzzles as payment to fight spam, it's interesting to look at the web page of the PennyBlack project at Microsoft Research, especially their Crypto 2003 paper by Dwork, Goldberg and Naor. Instead of using CPU-bound puzzles, they use memory-bound puzzles. The idea is that CPU speeds vary greatly between the fastest and slowest machines available today, which makes it difficult to compromise widespread acceptance of the slow but good machines AND control of the fast but spamming machines. On the other hand, memory bandwidths have a much narrower variance, which makes paying by "wasting one's memory bandwidth" more equitable among the slow and the fast. That's the approach taken in this project. It's a fascinating read (although, it has a bit of crypto, which could be heavy).
A very cool instance of the duality has been under research at Stanford, in Dawson Engler's group. They look at kernel "rules" as a programming language, and then they run a compiler checker on it to catch semantic bugs.
For example, lots of cases where locks where aquired but never released, or aquired twice in sequence in the Linux kernel were identified by considering the sequence "lock(x);...; relase(x);" as a language construct, and then looking for device drivers or modules that didn't abide by it.
I believe there was a Linux kernel subversion named after these guys, for finding a gazillion deadlocks and such bugs in an automatic fashion.
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Citibank offers a "Virtual Account Number" service for their credit cards (Mastercard). It works fairly well. You can do one-shot purchases, or recurring purchases with the same merchant only, or even cap the total you're willing to spend via a virtual number over a number of months.
They have a web interface, but you can also download a Java applet that can generate numbers and fill in purchase forms for you.
In fact, SkyOne viewers only have 2 episodes left to watch from the first season. The first season order was for 13 episodes. Episode 12 is showing next Monday. Check out TV Tome.
Related to the discussion of crypto puzzles as payment to fight spam, it's interesting to look at the web page of the PennyBlack project at Microsoft Research, especially their Crypto 2003 paper by Dwork, Goldberg and Naor. Instead of using CPU-bound puzzles, they use memory-bound puzzles. The idea is that CPU speeds vary greatly between the fastest and slowest machines available today, which makes it difficult to compromise widespread acceptance of the slow but good machines AND control of the fast but spamming machines. On the other hand, memory bandwidths have a much narrower variance, which makes paying by "wasting one's memory bandwidth" more equitable among the slow and the fast. That's the approach taken in this project. It's a fascinating read (although, it has a bit of crypto, which could be heavy).
A very cool instance of the duality has been under research at Stanford, in Dawson Engler's group. They look at kernel "rules" as a programming language, and then they run a compiler checker on it to catch semantic bugs.
...; relase(x);" as a language construct, and then looking for device drivers or modules that didn't abide by it.
For example, lots of cases where locks where aquired but never released, or aquired twice in sequence in the Linux kernel were identified by considering the sequence "lock(x);
I believe there was a Linux kernel subversion named after these guys, for finding a gazillion deadlocks and such bugs in an automatic fashion.
Take a look at their first paper on this.
They have a whole slew of updates to this at
Engler's web page. I believe there's a similar project at Berkeley as well.
Cheers,
bauzeau