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user2284570
user2284570
10:29 AM
@StackExchange Oh, I do remember 9/11. Like most peoples of my age, it was a sad day : no cartoons after school homeworks (finish your homework then you can watch tv).
 
user2284570
user2284570
10:48 AM
and I will vote for the first time in 2017.
 
 
2 hours later…
Rory Alsop
Rory Alsop
12:57 PM
I remember it well. It was a very odd day in the office, trying to continue working while watching everything unfold. Seeing the second plane hit live was a shock.
One of the reasons some of those conspiracy theorists annoy me so much with their nonsense, when they say it was a bomb and not a plane...
 
user2284570
user2284570
1:10 PM
@RoryAlsop : My point is voters to that election will all remember 9/11. But from a child point of vue.
 
Rory Alsop
Rory Alsop
1:28 PM
I assumed you were talking about from a child's point of view, as you mentioned school.
The xkcd is mentioning folks younger than you
 
 
1 hour later…
Journeyman Geek
Journeyman Geek
2:37 PM
@user2284570 I think the calculation I made is the youngest folk to vote would have been ~2 during 9-11
@RoryAlsop heh, I had examinations, so my parents had to keep shooing me off
 
 
1 hour later…
Developer
Developer
3:58 PM
hi
why hashes can't be guessed
 
 
2 hours later…
diagprov
diagprov
6:25 PM
@Developer I am assuming you are looking for a preimage of a hash. To put it another way if you have the hash 3fb7b39416f1d067268747fc214494d759d2609f863ace1a8a76705618d5c80b you want to know what was hashed to get this value.
The answer is simple. You can guess. Of course you can. However, the probability you will be right is extremely low, as in you are more likely to be struck by lightning twice and win the lottery three times than make a successful guess assuming a single guess.
This is assuming that hash functions are one-to-one, which they cannot be.
 
Developer
Developer
i don't understand how human can calculate something that they can't reverse back
i have little knowledge of how hashes are generated
but, regardless, I can't believe u develop something which can convert a string into hash, but can't convert hash back to string
 
diagprov
diagprov
Then I'd have a look into how SHA hashes work, e.g. SHA1 and SHA2, for example.
They follow what is called a merkle-damgard construction, a form of one way compression. So they start with an initial state and as you feed data to them they alter that state
If you like it is like a very large lock with those digit wheel things you can set to a combination to unlock
Start at a set combination and twiddle each wheel according to a specified algorithm
All the attacker gets is the wheels in their final position
and the knowledge of the algorithm and the initial state
what they don't know is all the data that went in
to trace your way back through all the intermediate states is incredibly complex
 
CodesInChaos
CodesInChaos
I know no one-way functions that are efficient enough for an ordinary human to compute in a reasonable time.
 
diagprov
diagprov
I think he means if we created it, why can't we undo it
in a more basic sense than that
but @Codes is right, we can't even compute them by hand ourselves efficiently. We'd be there forever.
Note that my description above is a simplified explanation of merkle-damgard. If you look into say SHA3, or @CodesInChaos work, you'll find those hashes work in a different way.
 
Gilles
Gilles
6:41 PM
43
Q: How does hashing work?

Griffin NowakI have been interested in Information Security. I was recently introduced to the idea of hashing. What I currently understand about hashing is that it takes the password a user enters. Then it randomly generates a "hash" using a bunch of variables and scrambling everything. Then when you enter th...

hash
 
 
1 hour later…
Developer
Developer
8:07 PM
@diagprov yes that's right...
@Gilles thanks, going to have a read
 
Developer
Developer
8:33 PM
my understanding now says
H(x) whereas H can be anything
so we have 2 way to crack the algorithm itself, 1st is to know the mechanics of it, and 2nd is ... just escaped my mind :/
so theoretically it's not impossible
 
 
1 hour later…
Henry WH Hack
Henry WH Hack
9:35 PM
BAD QUESION DETECTED.
 
 
1 hour later…
Rory Alsop
Rory Alsop
10:43 PM
@Developer - if you have a strong encryption algorithm, it doesn't matter if you know it. You still can't crack it. That's the whole point. Good encryption allows for an enemy to know the entire algorithm while still remaining secure
 

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