crypto - Imapenguin

Dice frequency

I've been obsessed with the Random number generator on the Commodore computers for a LONG time, and I'm not the only one who is, to be sure. We've used this random function in many of the Cipher series articles before, both via BASIC and directly getting randomness from the SID

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Quick Post: Modulus in BASIC 2 without a cartridge

I posted this on Twitter a few weeks ago, but a young lady has been exploring programming in Python and also with Commodore BASIC which is pretty neato. She's 11 and asked if there was a way to do modulo functions on Commodore BASIC because she's using her Dad's VIC-20

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Making and breaking Ciphers on the Commodore 64 Part 12 - Pontifex - Solitaire from Cryptonomicon

Cryptonomicon Pontifex/SolitaireWe're back to my favorite book for another round. We've done quite a bit with Cryptonomicon so far. One of my favorite moments is when Enoch Root introduces a cipher that two prisoners used to communicate using just a humble playing card deck. Drawing of the mine in

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Making and breaking Ciphers on the Commodore 64 Part 11 - One time pads on a Commodore 64, probably a bad idea

A while ago, I explained in detail how to generate one time pad sheets and use them to encrypt and decrypt messages. It turned out to be doable, only requiring a pencil and a way to create random numbers, but it's slow, error prone and tedious. WhyThe one time pad

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Making and breaking Ciphers on the Commodore 64 Part 10 - Finding hash collisions with a type in game from 1984

HashesWe did an implementation of a once popular hashing function in Part 8 on RC4 without really going into why. A hash function is any function that is used to map data of an arbitrary size (input) to a fixed size output. An algorithm is applied to the input and

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Making and Breaking Ciphers with Commodore 64 Part 9 - Finding Smallish Primes

RecapSo far we've Reversed a stringShifted bits left and right (mostly right)Brute forced a known simple cipherChanneled our inner John Connor by cracking ATM machinesSearched through a large number looking for matchesLearned how to use XOR to recover dataCreated a Linear Feedback Shift Register to generate better random numbersImplemented

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Making and breaking Ciphers on the Commodore 64 Part 8 - RC4

RecapSo far in this 8 part series on doing weird things with Ciphers on old computers we've: Reversed a stringShifted bits left and right (mostly right)Brute forced a known simple cipherChanneled our inner John Connor by cracking ATM machinesSearched through a large number looking for matchesLearned how to use

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Making and breaking Ciphers on the Commodore 64 Part 7 - Pseudo Random with Linear Congruential Generators

So far in this 7 part (shocked I've made it through 7!) series on doing weird things with Ciphers on old computers we've: Reversed a stringShifted bits left and right (mostly right)Brute forced a known simple cipherChanneled our inner John Connor by cracking ATM machinesSearched through a large number

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Making and Breaking Ciphers with a Commodore 64 - Part 6: XOR is Magical - Data recovery

ReviewSo far we've: Reversed a stringShifted bits left and right (mostly right)Brute forced a known simple cipherFaked it, but then looking for a 4 digit known pinSearched through a large number looking for matchesWe now have most of the basic skills in Assembly to start doing some real work.

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Quick post: Determining length in Commodore Assembly

A common task in our code is to determine the length of something. In this example, let's check the length of a string like "are you keeping up?" In Python, this is crazy easy. #!/usr/bin/env python message = "are you keeping up?" len(message) Python 3In 6510 Assembly, this

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Making and Breaking Ciphers with a Commodore 64 - Part 4: The PIN Program from Terminator 2

A few minutes into Terminator 2, the young John Connor takes his Atari Portfolio out of his bag and inserts a foil covered card into an ATM machine and proceeds to crack a pin number and steal some cash from an unsuspecting account. This is a movie prop and doesn't

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Making and Breaking Ciphers with a Commodore 64 - Part 3: The Caesar Cipher

Well here we are at part three and it's a lot to pack into one page. Let's build upon what I called the Shift Cipher and implement what is often referred to as the Caesar Cipher, although there is much debate on when this was really first done. The idea

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Making and Breaking Ciphers with Python, er Commodore- Part 2: The Shift Cipher

In Part 1 we did a simple reverse of a string. While simple, these software steps will help build the skills we need going forward in Assembly without feeling like I skipped right to a 300 line after doing a short one. One foot in front of the other and

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Making and Breaking Ciphers with Python, er, a Commodore- Part 1: The Reverse Cipher

Sometime during my weeklong exploration of SHA-256 on a Commodore realized that there was a whole world of exploration that could be explored. Just because a Computer system is old, doesn't mean it's not interesting or useful. I had expected it to take months to figure out the SHA-256 implementation,

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Simple, 'unbreakable' encryption with a pencil

Last week, at this bat-time on this bat-channel, I talked about checking off one of my 35 year old bucket list items by learning Commodore assembly language. (shut up, you're old too.) Coincidentally, I picked this up at the time I was re-reading Cryptonomicon by Neal Stephenson for the ump-teenth