Cryptology thread

Cryptology thread

Personally I'm more interested in ciphers rather than encryption but it all makes good learn (y)

Other urls found in this thread:

crypto.stackexchange.com/questions/24808/toy-public-private-key-example-open-to-frequency-analysis
mediafire.com/?zzda5ei3dixe5ld
pastebin.com/V0LAKtkD
mediafire.com/?3149nwh3681jnwc
twitter.com/AnonBabble

It's better with an animal factor. Check out cryptozoology.

Caesar Chiffre but every letter is moved according to the formula f(x)=2x^x*e^x where x = number of letter in text * number of letter in line

You get that from head?

how does rsa stop frequency analysis?
i know the message is mapped to the ciphertext by [math]c_i = m^e_i
(\mod N)[/math] for some number e with special properties (but that is also independent of i). but that ends up producing things like [math](1,2,3,1,1)\mapsto(18,23,11,18,18)[/math]. every lecture ive had on it seems to miss that part out. does it just magically work for larger numbers or is it something going on before the message is encrypted?

crypto.stackexchange.com/questions/24808/toy-public-private-key-example-open-to-frequency-analysis

Well it isn't encrypted letter by letter. The whole message is put into one number.

First each letter is converted to hexadecimal (using ascii or some table)

H E L L O

48 65 6C 6C 6F

Then each letter represents a digit, from most significant to least

48656C6C6F

As a decimal this is:

310939249775

This is m. You would also pad the message, too.

CFCF32C1281210
DB4ZF12C
1242DBEC21AZ512WDSD21F5G

I made a program that uses a vigenere cipher

written VB2008 cuz noob but i've uploaded it to media fire with the source code

forgot link -_-
mediafire.com/?zzda5ei3dixe5ld

What do you guys think of this idea for an encryption algorithm?

This would be used for relatively short messages. Basically, you pad the message with 10 times more random noise than the message length. When you encrypt, the message gets buried under all the other useless info.

I call it "The Verasian-Seev Gambit"

Two things: (1) this isn't an encryption algorithm, and (2) random padding has been a thing for a long, long time.

Blowing up the ciphertext size by a factor of 10 introduces practical concerns; any benefit you would see by doing this would be better achieved by simply using an encryption algorithm with better guarantees.

Very nice. Do you have any more programs to show us?

Can you pastebin your code?

I made a "spelling bee" program for A-Level and a few sorting algorithms in python but not much else. I recently learnt what a vigenere cipher is so I wanted to see if I could make a program to do it

Pastebin code is slightly updated
pastebin.com/V0LAKtkD

>Yeah let me just download a random ass VB.exe I downloaded from a crypto thread...

download visual studio 2008 and look at the code youre running if you like...
or dont w/e

A-Level computing was cancer = )

100% learned more on my own than from that course

Are you in uni now?

Yeah but I'm studying the wrong thing... Mechanical engineering, now I've got my mind set on changing courses, maths maybe

Hey guys. I have an idea for transposing text.

You have a "key" and you use the msg length+1 as the modulus.

For the [math]i^{th}[/math] character in the msg, you calculate it's new place like this:

key = 12
message is six characters long

1: (12*1) mod 7 = 5
2: (12*2) mod 7 = 3
3: (12*3) mod 7 = 1
4: (12*4) mod 7 = 6
5: (12*5) mod 7 = 4
6: (12*6) mod 7 = 2

(Also the key has to be coprime with the msg length+1 for this to work)

The key space for this is only msg length-2 (4 in this case) when you exclude the repeats and keys that just map the same letters, reverse letters or all zeros. But, maybe you can do many rounds of this, with randomizing keys.

Kinda related, check out rsa's malleabilty and pcks#1 for rsa. It's not used as is, and there are serious vulnerabilities if used without any changes.

This is a permutation cipher, so for low message lengths you can use anagrams and for longer lengths you can do frequency analysis. You can use different keys for different message lengths in the plaintext, but then you have n-tuples of keys and a possibly secret parameter for choosing where you changed the key. Which will make key exchange a bitch.

>implying i want to see the abomination that VB is

Cant really blame you there... but its only 178 lines altogether and is in a pastebin as well so yeah I wouldn't really say there's any risk

I have a fun challenge for crypto club.

Make a hashing algorithm in python. The rest of us try to find collisions and break your hash.

You going to start us off?

Bump. I'm taking an elementary number theory class and I wanna see how this all works

Just shit out a Caesar cipher program but its really too simple to even post

for a project i'm going to implement swifft in the next month or so. I'll post it here if I remember by then.

Aren't ciphers totally outdated with the advent of computerized encryption?

Yeah it's more of an interest/hobby
I'm studying math currently
But there is such a thing as an unbreakable cipher... Provided certain constraints (see. One Time Pad)
Not exactly practical still....

>using windows in Veeky Forums
>still using windows despite the latest cyberattack
>not knowing the difference of source code and executable

did you even read the thread

How does one get into cryptology/encryption etc? Next spring my university Math department is offering a "intro to crypto" class and i want to learn as much as i can before i go into it.
For reference ive taken advanced calc, lin algebra, lin analysis/systems of lin eqs. And will probably take a number theory class next quarter. Where should i start?

Wait this look really coll for beginners like me? Is it uploaded somewhere?

The VBproject is on my mediafire.
It's alright, it got me almost full marks on the programming section. There's still a few bugs maybe some validation issues but nothing too major.

mediafire.com/?3149nwh3681jnwc

I've made a ReadMe and put it in the .rar

>pretending Linux has the same software options as Windows
>pretending Linux is ""more secure"" than Windows

Both are false, all software is complete shit and we'll always have this problem. Also Windows has nearly all of the market share, so that's the primary reason why it's targetted.

Know a shit load of Algebra & Number Theory with a sprinkle of analysis. Then just buy "Introduction To Mathematical Cryptography" (Springer) and you should be good.

Joint up. if youre interested you will enjoy learning and it wont feel like work at all. start off working with smaller simple things and getting to grips with the concepts

Apparently this is the right way round to view it.

The last part is only small and apparantly a small amount of concealment has been used aswell