## What Is Entropy In Cryptography?

In cryptography, entropy refers to the randomness collected by a system for use in algorithms that require random data. A lack of good entropy can leave a cryptosystem vulnerable and unable to encrypt data securely.

## Basic Intro to Elliptic Curve Cryptography

Elliptic Curve Cryptography is a modern public-key encryption technique based on mathematical elliptic curves that is known for producing smaller, faster, and more efficient cryptographic keys. Bitcoin, for example, uses ECC as an asymmetric cryptosystem because it is so lightweight. In this introduction to ECC, I want to focus on the main ideas that make …

## Is AES-256 Quantum Resistant?

With quantum computers getting more powerful each year, many worry about the safety of modern encryption standards. As quantum computers improve in performance and the number of qubits used for calculations increases, current cryptosystems are under threat. AES-256 is one of the most powerful symmetric ciphers, but will it remain secure in a post-quantum world? …

## Bcrypt Step by Step

Bcrypt is a key derivation function, which can be thought of as a special kind of hash function. Its purpose is to slowly convert a piece of input data to a fixed-size, deterministic, and unpredictable output. A common use case is to convert a password into an n-bit cryptographic key, which can then be used …

## (Very) Basic Intro to Lattices in Cryptography

Lattice-based cryptography, an important contender in the race for quantum-safe encryption, describes constructions of cryptographic primitives that involve mathematical lattices. Lattices as they relate to crypto have been coming into the spotlight recently. In January 2019, Many of the semifinalists in the NIST post-quantum-cryptography competition were based on lattices. Lattice-based cryptography has promising aspects that give us hope …

## Shamir’s Secret Sharing Step-By-Step

Adi Shamir’s Secret Sharing is a cryptographic algorithm that allows distinct parties to jointly share ownership of a single secret by holding shares. The original secret can only be reconstructed by using a minimum number of shares, which allows different parties to cooperate without the need to fully trust one another. Example Problem To illustrate, …

## “Practical Cryptography” Course Released

We just launched our new Practical Cryptography course, a code-in-the-browser tutorial where students build cryptographic functions in the Go programming language. Practical Cryptography stands out among online cryptography courses because it not only teaches crypto fundamentals, but it allows users to get hands-on experience building out the code. What’s Included? The course has four modules …

## They Who Control Encryption

If you’ve seen The Imitation Game or studied computer science in school, you have likely heard of Enigma, Alan Turing, or some of the other advances in cryptography that took place during the Second World War. During this time and until the 1970s, governments from around the world had near-total control of all cryptographic systems. …

## HMAC and MACs – The Inner Workings of JWTs

HMACs and MACs are authentication codes and are often the backbone of JWT authentication systems. A Message Authentication Code (MAC) is a string of bits that depends on a secret key and is sent with a message to prove the message wasn’t tampered with. HMACs are a more strict version of MACs that offer additional …

## (Very) Basic Intro to PGP (GPG)

PGP, or its open-source alternative, GPG, is a program used to encrypt data such that only an authorized party can decrypt it. In this introduction, we will cover its use-cases and a high-level overview of the algorithms involved. Both programs (and others) adhere to the OpenPGP protocol. Because it is an implementation agnostic protocol, people …