Crypto

Solving the classic N-Queens puzzle using backtracking. Covers both iterative and recursive approaches with implementations on the Commodore 64.

Exploring the elegant maze generator from Compute! magazine (December 1981). A line-by-line breakdown of how this classic BASIC algorithm works.

Writing code to validate Pilish text—prose where word lengths match the digits of Pi. Implementations in Julia and Commodore BASIC.

Evaluating vintage computers for NaNoWriMo 2022: VIC-20, Plus/4, Commodore 64, and PET. Word processing on 8-bit machines with SpeedScript and other …

Adding integers with hundreds of digits using string manipulation in Commodore BASIC. When your numbers are too big for Wolfram Alpha.

Understanding the MOS paper tape format used by the KIM-1 and other 6502 systems. Breaking down the hex format line by line with checksum …

Implementing 64-bit arithmetic in 6502 assembly to solve the wheat and chessboard problem. Handling numbers too large for standard calculators on …

Visualizing the poor randomness of RND() on the Commodore 64 and 128 compared to the PET and Plus/4. Clear patterns emerge when you plot the output.

Testing the Commodore 64’s random number generator by simulating dice rolls and comparing the frequency distribution to theoretical values.

How to perform modulo operations in Commodore BASIC 2 without a cartridge. A one-line solution for VIC-20 and C64.

Implementing Pontifex/Solitaire—the playing card cipher from Cryptonomicon designed by Bruce Schneier—on the Commodore 64.

Generating one-time pads on a Commodore 64. Probably a bad idea for real security, but it looks cool.

Understanding hash collisions by finding them in a simple checksum from a 1984 type-in game. Demonstrating why weak hashes fail.

Finding prime numbers on the Commodore 64 for cryptographic purposes. A practical introduction to primes and primality testing.

Implementing the RC4 stream cipher on the Commodore 64, exploring the algorithm that powered WEP, WPA, and many other encryption protocols.

Exploring pseudo-random number generation on the Commodore 64 using Linear Congruential Generators, a key building block for cryptographic …

Understanding the XOR operation and its magical properties for data recovery in cryptography and disk storage on the Commodore 64.

A quick tutorial on determining string length in 6510 assembly language, comparing the approach to Python’s simple len() function.

Recreating the Terminator 2 ATM PIN cracker scene on the Commodore 64, using SID chip random numbers and 6502 assembly.

Building a Caesar cipher encoder and brute-force decoder on the Commodore 64, demonstrating how to crack simple substitution ciphers programmatically.

Implementing the shift cipher on the Commodore 64, encoding messages by rotating alphabet positions similar to a physical code wheel.

Starting a series on implementing ciphers in Commodore assembly language, beginning with a simple string reversal as the first building block.

Implementing a one-time pad cipher by hand using dice-generated random numbers, inspired by the encryption methods in Cryptonomicon.