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Cryptography

MD4: From Hero to Zero

Before MD5, there was MD4. Designed for speed above all else, MD4 became the foundation for an entire generation of hash functions—and a cautionary tale about prioritizing performance over security. Today, MD4 is so thoroughly broken that collisions can be computed by hand. This post traces MD4's

SHA-1: From Hero to Zero

For two decades, SHA-1 was the backbone of internet security—protecting SSL certificates, signing software, and verifying Git commits. Then in 2017, Google shattered it. Literally. This post traces SHA-1's journey from government-approved standard to cryptographic casualty, culminating in the SHAttered attack that proved its collision resistance was

MD5: From Hero to Zero

In 1991, MD5 was the gold standard of cryptographic hash functions. Today, it's a cautionary tale in cryptographic history. This post traces MD5's journey from trusted workhorse to deprecated relic, and the attacks that brought it down. What is MD5? MD5 (Message-Digest Algorithm 5) is a

Understanding SSH Key Random Art

Understanding SSH Key Random Art

When you generate an SSH key pair, you might have noticed a peculiar ASCII art image appear alongside your key fingerprint: +--[ED25519 256]--+ | .o+= | | . .o.o | | . + .+ | | . = B .o | | . + S + . | | o + = o . | | . o B = .. ..| | . = * o..o.o| | E . o.oo+=+| +----[SHA256]-----+ This image is called randomart, and

The Mathematics of RSA Encryption

The Mathematics of RSA Encryption

RSA is one of those things that sounds complex until someone explains it with a clear example. Let's break it down step-by-step, with small, human-readable numbers, so it's easy to follow and fun to understand. What is RSA? RSA is a powerful and widely-used asymmetric encryption

How to Forge a JWT with C#

How to Forge a JWT with C#

When running tests on APIs we need to be able to create tokens that have specific characteristics to make sure the API responds correctly to each test scenario. I developed a C# script that allows me to do just that. very simple, it can be improved and more options can

AES GCM in .NET 8 (.csx script)

AES GCM in .NET 8 (.csx script)

Well, sooner or later, I would need a way to encrypt things, a safe way, therefore here I leave the code for AES GCM string encryption with .NET 8. I assume you already have .NET 8 installed as well as dotnet-script. #!/usr/bin/env dotnet-script /* ====================================================================== + AES-GCM (Galois/Counter Mode) -