How-To - Imapenguin

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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Quick Post: Slow text on the Commodore

An "almost teenager", Josh, sent me an email yesterday asking how I do slow text on the Commodore. He is just starting assembly at 12 which is pretty impressive. He's been using KickAssembler, but wants to try it "on hardware". It's not difficult really. There are probably a lot of

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The Commodore 64 N.O.O.C.U.L.A.R. futbal project

ConceptI'm fortunate to have a number of vintage computers I've collected over the years. Some were fun finds, others donated. One I've had since 1983 (we think) and it's one of my most prized possessions. I travel a fair bit and not long ago I was looking for something for

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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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Repairing a Commodore 128 and DIY Chris's RAM tester review

I have several items from DIY Chris that we'll review over the next week including a GAL PLA and flash-able ROM drop in that can hold kernal, character or BASIC ROMs. First on the list is the RAM tester. The problem child 128I have a Commodore 128 which developed a

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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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Jiffies in Assembly

Many of you know that you can use a "Jiffy" on a Commodore as a measure of time. Sorta. The short short version is that we have a 3 byte clock that increments once every interrupt, so 1/60th of a second. It's not considered reliable as a real time

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Making and Breaking Ciphers with a Commodore 64 - Part 5: Wargames

Let's recap a littleSo 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 pinWhat we need next in our toolbox is to be able to search through a large number of values to

code

Calculating Pi via the Gregory-Leibniz series in BASIC on the VIC-20

It's Pi day tomorrow, and you know what that means! Cherry is favorite. Apple is second favorite. There is a well known and easy to understand method for calculating Pi with the Gregory Leibniz series. Leibniz built on the work on Gregory. It has the added benefit of being pretty

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Quick Post: Commodore 64 Simple Addition Efficiency

There are many hacks you can do in Assembly language on the Commodore. Here's a very easy one with impressive results according to my analog stopwatch. We want to count to $ffffff or 2563 (224) which is 16,777,216 We wont print to the screen to save a lot

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c0pperdragon verdict

Ahh, the quest for a better Vintage computer picture never ends. I'm having fun with it anyway. Side thought: At what point does a computer cross over from old: no one wants that 2007 Windows tower you built in your basement, to OMG, it's Vintage, let's drive up the eBay

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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 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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Replacing an RF Modulator on a Commodore 64C

The output on my newest Commodore 64 (1989) is pretty marginal. The colors are okay(ish) but the text lines are clearly bleeding and the picture is very muddy. Most vintage computers don't do red text on blue very well, but this one is particularly painful. Red on dark blue

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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

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Getting started with Native Commodore 64 Assembly

Some time in the month of September 2020 I dug out the old Commodore 64 that my Dad bought for himself in 1983. It quickly migrated its way into my room and stayed there until 1993 when I joined the Navy. Someone in my family, probably Mom, carefully packed it

linux

Switching to 64 bit Raspbian Linux is a snap

Have you been itching to do 64 Bit ARM assembly program like I have on your Raspberry Pi? I'll bet you have. I mean, the thing has to be useful for SOMETHING right? Most Raspbian installs are still on 32 bits, but switching is easy. Make backups and all that