# Any crypto nerds here? (Crypto nerd hangout spot)



## Zeroknight (Oct 7, 2009)

Hello fellow Cubers. It has come to my attention that we are a very diverse community, and such have varying interests. Possibly Cryptography could be one of them?

If you do like Crypto, we can talk about all aspects of it here: from AES, and MD5 to Purple and monoalphabetic substitutions.



I assume that I'll be the only one here, but I'll launch this topic anyway


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## V-te (Oct 7, 2009)

I might get into it in the future. It interests me a bit, but I still don't know the basics. I'll be coming back here, see how it is.


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## TacticalPenguin (Oct 7, 2009)

I have a good amount of interest in the topic and am familiar with most of the basics of it but I can't say I actually know too much about it - it fascinates me though.


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## Lucas Garron (Oct 7, 2009)

Fun trivia: MD5 hashes were used to authenticate live updates of every single time entered at SF09. (It was, and probably will remain for a while, the only live results system where every time was updated online immediately after being entered.)

Independently, who's read In Code?


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## Zeroknight (Oct 7, 2009)

Yes people came! I, myself am still in the process of learning crypto., but later, (when I'm not at school), I'll post some resources for you guys. Bitwise operators, types of ciphers, (possibly pentesting software...), all of that good stuff.

PS: Lucas, I knew you would come, I figured you loved Crypto as much as, if not more than me.


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## Zeroknight (Nov 10, 2009)

I'll bump this topic in the hope that when I had originally made it, people weren't around


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## hawkmp4 (Nov 10, 2009)

TacticalPenguin said:


> I have a good amount of interest in the topic and am familiar with most of the basics of it but I can't say I actually know too much about it - it fascinates me though.



This one.


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## daniel0731ex (Nov 10, 2009)

bump


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## miniGOINGS (Nov 10, 2009)

daniel0731ex said:


> bump



A 3 minute bump? You win.


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## Cyrus C. (Nov 10, 2009)

I'm not sure if we're talking about the same crypto, but we sometimes play crypto in my honours geometry class.


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## hawkmp4 (Nov 10, 2009)

No, he's referring to cryptography.


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## LewisJ (Nov 10, 2009)

Cyrus C. said:


> I'm not sure if we're talking about the same crypto, but we sometimes play crypto in my honours geometry class.



No, that wouldn't be the same crypto. Cryptography is a lovely art and science, I doubt that a game played in a geometry class compares. 

That said, describe this game.


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## OregonTrail (Nov 10, 2009)

For an absolutely incredible explanation of AES, check out Security Now! episode 125.

In fact, the entire series is amazing. Listening to SN alone got me 6th place at FBLA's national level computer security competition (and a free one week vacation from my school :3) At the time I had listened to episodes 1-131.


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## Ton (Nov 10, 2009)

Zeroknight said:


> I assume that I'll be the only one here, but I'll launch this topic anyway



Not really cryptography and coding theory was part of my study, in real live I am more busy with encoding (compression) that with the cryptography part. But it is fun to crack codes. As I did with Wordperfect, where a program of mine ended in a quote in a book.....


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## LNZ (Nov 10, 2009)

Many years ago (2006-7) in fact, there was a thread in the Australian dol forums that posts were submitted in binary ascii or hexadecimal ascii. I posted many posts in this thread. And others did too.

Here's an example in binary ascii (posted November 15, 2006). I now have no idea what this is in plain english now. Decode at your own risk!

01011001 01101111 01110101 00100000 01110111 01101001 01101100 01101100 00100000 01110100 01100001 01101011 01100101 00100000 01100001 01101110 01111001 00100000 01101111 01110000 01110000 01101111 01110010 01110100 01110101 01101110 01101001 01110100 01111001 00100000 01110111 01101111 01101110 00100111 01110100 00100000 01111001 01101111 01110101 00100000 01000001 01101110 01100111 01100101 01101100 00101110 00100000 00001101 00001010 01101111 01101111 01110100 00101100 00100000 01110010 01100001 01100101 01110111 01110011 00100000 01110011 01100101 01101101 01101001 01110100 01100101 01101101 01101111 01110011 00100000 01001001

One in hexadecimal ascii. (January 4, 2007). No idea of this message now. Decode at your own risk!

49 27 6D 20 76 65 72 79 20 62 6F 72 65 64 20 72 69 67 68 74 20 6E 6F 77 20 74 6F 6F 21 20 53 6F 20 74 68 69 73 20 69 73 20 6A 75 73 74 20 61 6E 6F 74 68 65 72 20 75 73 65 6C 65 73 73 20 70 6F 73 74 20 66 72 6F 6D 20 6D 65 2E 20 49 74 20 77 69 6C 6C 20 6D 61 6B 65 20 6D 65 2E 20 41 6E 64 20 74 68 69 73 20 77 69 6C 6C 20 74 61 6B 65 20 6D 65 20 6F 6E 65 20 70 6F 73 74 20 63 6C 6F 73 65 72 20 74 6F 20 74 68 65 20 72 65 6D 61 72 6B 61 62 6C 65 20 66 69 67 75 72 65 20 6F 66 20 31 30 30 30 30 20 70 6F 73 74 73 21 20 57 72 69 74 74 65 6E 20 62 79 20 61 6E 67 65 6C 31 38 30 31 20 6F 6E 20 30 34 2F 30 31 2F 32 30 30 37 20 61 74 20 31 31 3A 32 30 70 6D 20 28 45 44 53 54 29


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## hawkmp4 (Nov 10, 2009)

For those who are curious, the first message-


Spoiler



You will take any opportunity won't you Angel. 
oot, raews semitemos I


second-


Spoiler



I'm very bored right now too! So this is just another useless post from me. It will make me. And this will take me one post closer to the remarkable figure of 10000 posts! Written by angel1801 on 04/01/2007 at 11:20pm (EDST)


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## LewisJ (Nov 10, 2009)

hawkmp4 said:


> For those who are curious, the first message-
> 
> 
> Spoiler
> ...



But did you go to the extent of writing your own script to find these?
I'm such a nerd...


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## hawkmp4 (Nov 10, 2009)

Yes I did. Pretty simple in Python, actually.


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## calekewbs (Nov 10, 2009)

lol in my gifted class we did a short section on cryptograms and fun stuff like that. But we never got really into it. My favorite type of code to make is a matrix code. they are quite fun.


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## Cride5 (Nov 10, 2009)

Bit of a random question:

Does anyone know whether there is a security advantage of dynamically generating s-boxes based on the key over using pre-set ones? As far as I'm aware the exact configuration of an s-box has quite big security implications. A poorly chosen one will result in a statistical weakness in the cypher. It would seem that basing them on the key may result in the strength of the cypher being dependent on the exact key chosen.

The AES algorithm Rijndael makes use of carefully chosen pre-set s-boxes, while Twofish (an AES finalist) bases them on the key. Aside from performance, was this perhaps part of the reason it wasn't chosen for AES?


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## LewisJ (Nov 10, 2009)

While rijndael theoretically might be easier to crack than twofish and serpent (that was the third finalist IIRC), a lot of the reason why it was chosen for the AES standard was its speed; while twofish and serpent may be slightly more difficult to crack (note that AES would still take all the computing power we have longer than the age of the universe to break or something ridiculous like that), AES pulls it off much more quickly and the sboxes being preset vs key-based might have something to do with that.


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