Today we’re going to talk about one of the most exciting developments in hash functions: Blake2.

Before anything else what is a hash function? It’s basically a mathematical algorithm that takes an input of any size and spits out a fixed-size output, known as the “hash” or “digest.” The beauty of hash functions is that they are one-way: you can’t reverse engineer the original data from the hash. This makes them perfect for securing sensitive information like passwords or financial transactions.

Now Blake2 specifically. It was developed by a team led by Jean-Pierre Aumasson and published in 2017 as an alternative to SHA-3, MD5, and other popular hash functions that have been around for decades. The main selling point of Blake2 is its speed: it’s up to twice as fast as SHA-2 on average, with a smaller memory footprint to boot.

But what really sets Blake2 apart from the competition is its flexibility. It supports keyed mode (which we’ll talk about in a minute), salted hashing, personalization, and tree hashing all of which are essential for securing data in real-world applications. Let’s have a better look at each one:

1) Keyed Mode: This is a faster and simpler replacement for HMAC (Hash Message Authentication Code). It allows you to add an additional key to the hash function, making it more secure against attacks like replay or denial-of-service. For example, let’s say you want to store user passwords in your database using Blake2. Instead of hashing each password separately and storing them all together (which can be vulnerable to dictionary attacks), you could use keyed mode with a unique salt for each user. This would make it much harder for attackers to guess the original password, even if they manage to steal the hash values from your database.

2) Salted Hashing: Similar to keyed mode, but instead of using a secret key, you add a random “salt” (a unique value that’s added to each input before hashing) to prevent attackers from guessing the original data based on common patterns or dictionary words. For example, let’s say you want to store user passwords in your database using Blake2 with salted hashing. Instead of storing the plaintext passwords themselves, you could hash them together with a unique salt for each user (which is also stored securely). This would make it much harder for attackers to guess the original passwords, even if they manage to steal the hash values from your database.

3) Personalization: Blake2 allows you to add additional data (“personalization”) to the input before hashing, which can be useful in certain applications like digital signatures or message authentication codes (MACs). For example, let’s say you want to create a MAC for a message using Blake2. Instead of just hashing the message itself, you could hash it together with some additional data (“personalization”) that identifies the sender and recipient. This would make it much harder for attackers to tamper with or replay messages without being detected.

4) Tree Hashing: Blake2 supports tree hashing, which is useful in certain applications like distributed databases or peer-to-peer networks where data needs to be shared across multiple nodes. For example, let’s say you have a large dataset that needs to be stored on multiple servers. Instead of storing the entire dataset on each server (which can be expensive and time-consuming), you could use tree hashing to create a “merkle tree” where each node is hashed together with its children before being sent to the next level. This would make it much easier to verify that the data hasn’t been tampered with or corrupted during transmission, without having to send the entire dataset over the network.

If you want to learn more about this exciting new hash function (and maybe even try it out for yourself), I highly recommend checking out the official documentation or downloading the source code from GitHub. And if you’re feeling adventurous, why not write your own implementation in Python or another programming language? Who knows you might just discover a new use case that nobody else has thought of yet!