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I stumbled upon a game today, it’s called Petals Around the Rose. It’s played with 5 dice, and you can only be told these three things about the game:

1. The name of the game is significant.
2. The number of petals comes from the dice, there’s only one answer for each roll and it’s either 0 or an even number.

1. You can be told the number of petals after each roll.

Your goal is to figure out how many petals are around the rose before you are told. To play it, visit this page (you need to have a browser that supports Flash).

Supposedly, the smarter you are, the longer it takes you to solve (it took a university professor a year), but I think that it’s just a matter of not over-complicating things. Often you look hard for a solution while it’s right there in front of you the whole time, and this is why you will feel cheated if you mull hard over it. There is another interesting article on this game, it’s a nice read and it’s where I realised the solution to the game (it doesn’t contain spoilers though).

Some time ago I thought of an authentication scheme for website registration (or anything else) using asymmetric encryption, which went something like this (Alice is the user, Bob is the server):

1. Alice signs up for an account and gives her public key to Bob.
2. Bob stores it.

1. When Alice wants to log on to Bob’s site, Bob sends her a random number of sufficient length, Alice signs it, Bob verifies that it is indeed she, and he logs her on.

At the time I hadn’t seen this protocol anywhere, and I was wondering why noone used it since it has so many advantages. I recently read Bruce Schneier’s Applied Cryptography (an excellent book) and (not very surprisingly) saw my scheme in it. As Schneier noted, “It is foolish to encrypt arbitrary strings—not only those sent by untrusted third parties, but under any circumstances at all.” Indeed, someone might mount a chosen-plaintext attack or, more simply, make you sign “I wear women’s underwear”. That would not be very flattering.

OK, it’s like this: Originally I had one 80 GB disk, one 120 GB disk and a 160 GB one that stopped working three months after I bought it (damn Maxtor). Last week I got a 250 GB Seagate Barracuda so I’d finally have some space (all the other disks were full).

The new disk arrived, I ghosted the 80 one on the 250 (after quite a few crashes and hangs, which after a while stopped), and I installed the 80 on my fileserver, while still keeping the files as a backup. Three days ago I decided the new disk was working well enough, so I formatted the old one and went on my way, when suddenly yesterday the 120 spun down and hung the entire system. I removed and replugged the cable and it worked, but as a precaution I copied everything on it to the 250 (which still had 30 GB left). I decided that I’d delete it when I needed the space if the other disk was working fine.

I have posted a new Python script on the scripts page, it will be very useful to you if you regularly burn CDs or DVDs. Try it out.

A few days ago I stumbled upon this great website called Moviepig. In short, it will tell you if you’re going to like a movie or not. You tell it a list of movies you have seen in order of preference (most liked to least liked) and then you ask it how much you’re going to like a movie you haven’t seen. It uses collaborative filtering to search for other people with the same tastes as you and tells you how much they liked the movie. It’s quite handy, and it beats asking all your friends and then coming up with nothing because they have different tastes than you or re

All done, hopefully everything works. If you notice that something is amiss, please email me using the link on the top right or leave a comment in the page (you probably need to create an account to do that). Thanks.

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