Which definition is correct? If an encryption scheme satisfies Perfect Secrecy, then it also satisfies Perfect Indistinguishability. Turns out that these two fundamental concepts in cryptography are mathematically equivalent to each other! Perfect Secrecy means that observing a

DVD Encryption Explained DVDs protect their content using a cryptosystem called Content Scrambling System (CSS). At its core, CSS uses a combination of Linear Feedback Shift Registers (LFSRs) that work together to generate a cipher stream, which is then XORed with the video

What is the entropy of Bingo? Entropy measures the unpredictability of information – a mathematical way to quantify randomness. In 1948, Claude Shannon introduced this concept that would become fundamental to cryptography, helping us measure how random (and therefore secure) our

What are Multi-set Hash Functions? Multi-set Hash Functions are hash functions with two key properties: 1) They're order-independent (the sequence of inputs doesn't affect the output) and 2) They're collision-resistant (it's computationally infeasible to find two different sets

Understanding Shamir's Secret Sharing: A Visual Guide Shamir's Secret Sharing is a powerful cryptographic algorithm that allows you to split a secret (like a key or password) into multiple shares, with a clever twist: you need a minimum number of shares to reconstruct the

Onion Routing Visualized 🧅 Onion Routing creates anonymous networks by nesting multiple layers of encryption around the message. Each network node removes one layer of encryption until reaching the core message, like peeling an onion. The message passes through multiple nodes,

Commitment Schemes: Cryptographic Safes How do commitment schemes work? A commitment scheme acts like a cryptographic vault, where a message gets sealed now, then later it's revealed. It uses two key functions: commit (locks the message) and verify (proves it wasn't changed

An evolution of PLONKish proof systems (2019-2024)

Pollard's Rho Algorithm in One Page

Inside SHA1: A Visual Breakdown SHA1 (Secure Hash Algorithm 1) transforms any input message into a 160-bit message digest through these key steps: 1. Preprocessing: The input message gets padded and parsed into a 512-bit block. A single '1' bit is appended, followed by enough

Secure Two-Party Computation: How Garbled Circuits Work Garbled circuits are cryptographic protocols that allow two parties to compute a function (described as a boolean circuit) together while keeping their individual inputs private. One party (the garbler) encrypts a boolean

Love at First Decrypt: Matchmaking Encryption Matchmaking Encryption allows messages to stay secret unless both sender and receiver are compatible! Just like a dating app, this cryptographic system only reveals messages when both parties match each other's criteria - keeping

Math Notation Cheat Sheet for Cryptography

Soundness v Completeness Guide

Feistel Networks Visualized Feistel Networks are a symmetric encryption structure where data is split into left (L) and right (R) halves, then transformed through multiple rounds of mixing and substitution using key-dependent functions. The same structure works in reverse for