https://panman4040.github.io/tags/cryptohack/Recent content in CryptoHack on an's security blogHugoenMon, 04 May 2026 21:12:44 +0800https://panman4040.github.io/training/cryptohack/modular_arithmetic/Mon, 04 May 2026 11:58:16 +0800https://panman4040.github.io/training/cryptohack/modular_arithmetic/<h1 id="modular-arithmetic">Modular Arithmetic</h1> <p>This module (no pun intended) introduces modular arithmetic, which is a critical mathematical edge for cryptography. Here are my important remarks:</p> <h2 id="euclidean-algorithm">Euclidean Algorithm</h2> <p>This is a very famous algorithm designed to calculate the GCD of two integers. I initially struggled trying to understand the intuition, but the following analogy helps:</p> <p>You are a carpenter. You have two wooden planks of different lengths, say Plank A is 105 inches long, Plank B 24. Our goal is to find a &ldquo;ruler&rdquo; that measures perfectly both plank from end-to-end.</p>https://panman4040.github.io/training/cryptohack/Mon, 04 May 2026 07:23:16 +0700https://panman4040.github.io/training/cryptohack/https://panman4040.github.io/training/cryptohack/introduction_to_cryptohack/Mon, 27 Apr 2026 07:23:16 +0700https://panman4040.github.io/training/cryptohack/introduction_to_cryptohack/<h1 id="introduction-to-cryptohack">Introduction to CryptoHack</h1> <p>Since this is an introduction, these are pretty straightforward stuffs. But there are a few notes to consider:</p> <h2 id="base64">Base64</h2> <p>This allows us to represent binary data as an ASCII string using an alphabet of 64 characters. One character of a Base64 string encodes 6 binary digits (bits), and so 4 characters of Base64 encode three 8-bit bytes.</p> <p>There is also padding introduced when the number of bits is not divisible by 6. Read more here: <a href="https://en.wikipedia.org/wiki/Base64#Examples">https://en.wikipedia.org/wiki/Base64#Examples</a></p>