The last things we studied in Arithmetic are the Reed-Solomon codes. It's a type of code you use to, not encrypt your information, but create redundant information in your final code. So when you read your code, if there are errors or missing parts, you can still decode it. It's not perfectly redundant like dog's ADN is. The redundant code is changed in a certain way so you can guess what the missing parts are.
A few days ago I was on the road to La Fête des Lumières (in Lyon) with 4 germans I met in Bordeaux. The driver had an old CD with a few mainstream and german songs on it that he wanted to play, problem, the CD was damaged, solution? None. Didn't need a solution. The CD still played, although sometimes it was indeed jumping, most of the time it was playing correctly. How is that?
Well, the information burned on the CD is coded thanks to Reed-Solomon's algorithm so that you can still guess what was burned on it through particular redundant code. This redundant code is (and I'm taking a guess here) what is used when your computer asks you "do you want to check if there was no error?" right after burning your CD.
more info on wikipedia
Today I was interviewed by Emeline Marceau from Direct Martin Bordeaux, a free newspaper that is directly competing against 20 minutes in France.
I already had my first interview with Vincent Glad from Slate (and now Canal+) 3 years ago. But this is different as it should be printed in a real newspaper with a picture of me. Well nothing is sure yet, crossing fingers.
The Pirate Bay, literally surfing the web with their pirate ship, changing their URL once again. more info
I've always stored plain passwords in cookies. And today I decided to educate myself about cookies a bit. Well, I was expecting that : you should not store plain passwords in cookies.
Basically, if your computer gets compromised, everyone can read what's in your cookies. So you'd better not store important information that are not encrypted.
What is the work around ? Storing a token + his identification. When someone logs in, I create a random token and store it in the database under its name.
Next time the guy comes around, I see that he has a token, I check if its identification coincides with the token, if it does I log the guy in.
I've seen hardcore implementations where the token (in the database, and in the guy's cookies) is refreshed on every page. I find that a bit troublesome as the cookie expires after 5 days (in my implementation) so it's no big risks.
I could also have put a timestamp forbidding anyone to log in with that token after 5 days. But I feel like it would be over protecting.
塞翁失马
posted December 2013
ran into that fable, made me think of bitcoins and litecoins.
A farmer had only one horse. One day, his horse ran away.
All the neighbors came by saying, “I'm so sorry. This is such bad news. You must be so upset.”
The man just said, “We'll see.”
A few days later, his horse came back with twenty wild horses following. The man and his son corraled all 21 horses.
All the neighbors came by saying, “Congratulations! This is such good news. You must be so happy!”
The man just said, “We'll see.”
One of the wild horses kicked the man's only son, breaking both his legs.
All the neighbors came by saying, “I'm so sorry. This is such bad news. You must be so upset.”
The man just said, “We'll see.”
The country went to war, and every able-bodied young man was drafted to fight. The war was terrible and killed every young man, but the farmer's son was spared, since his broken legs prevented him from being drafted.
All the neighbors came by saying, “Congratulations! This is such good news. You must be so happy!”
The man just said, “We'll see.”
Here it is, Lamborghini is now accepting bitcoins and the first purchase was made for a Tesla.
"Lamborghini Newport Beach is proud to announce that we are fully capable of accepting Bitcoin as legal tender for vehicles, We are excited to be opening the door to this new currency."
more info here
Ahhhh, what is P, NP, NP-Complete and NP-hard. Found this 