Today we’re going to talk about one of the most exciting developments in hash functions: BLAKE2. If you’ve been following along with our previous guides on SHA-1 and MD5, you know that these oldies but goodies have some serious security flaws. But don’t freak out, because BLAKE2 is here to save the day!

BLAKE2 is a cryptographic hash function defined in RFC 7693, which means it’s been thoroughly vetted by the crypto community and has undergone rigorous testing for security vulnerabilities. It comes in two flavors: BLAKE2b (optimized for 64-bit platforms) and BLAKE2s (optimized for smaller platforms).

One of the coolest things about BLAKE2 is that it supports keyed mode, which means you can use a secret key to create a hash function that’s unique to your application. This is great if you want to add an extra layer of security to sensitive data or prevent attackers from using precomputed rainbow tables against your system.

Another awesome feature of BLAKE2 is salted hashing, which involves adding a random value (called a “salt”) to the input before computing the hash. This makes it much harder for attackers to use precomputed hash values to crack passwords or other sensitive data.

Personalization is another neat trick that BLAKE2 supports. It allows you to customize the hash function by adding your own “personal” value, which can be useful if you want to create a unique hash for each user on your system. This can help prevent attackers from using precomputed rainbow tables against your application.

Finally, BLAKE2 supports tree hashing, which is great if you need to compute the hash of large datasets or files that are too big to fit into memory all at once. Tree hashing involves breaking up the data into smaller chunks and computing a hash for each chunk, then combining those hashes together using a special algorithm.

So how do we use BLAKE2 in our code? Let’s take a look at an example:

# Import the hashlib library, which contains the BLAKE2b hashing algorithm
import hashlib

# Create a new BLAKE2b object with a 32-byte digest size and a secret key of "my_secret_key"
# The digest size determines the length of the resulting hash, while the key adds an extra layer of security
hash = hashlib.blake2b(digest_size=32, key="my_secret_key".encode("utf-8"))

# Add some data to the hash object
# The update() function adds data to the hash object, which will be used to compute the final hash value
# In this case, we are adding the string "Hello, world!" encoded in bytes
hash.update(b"Hello, world!")

# Compute the final hash value and print it out
# The hexdigest() function returns the final hash value in hexadecimal format
print(hash.hexdigest())

In this example, we’re creating a new BLAKE2b object with a 32-byte digest size (which is equivalent to 128 bits) and a secret key of “my_secret_key”. We then add some data (“Hello, world!”) to the hash object using the `update()` method. Finally, we compute the final hash value using the `hexdigest()` method and print it out in hexadecimal format.

And that’s all there is to it! BLAKE2 is a powerful and versatile hash function that can be used for keyed mode, salted hashing, personalization, and tree hashing. So why wait? Give it a try today and see how much faster and more secure your applications can be with this exciting new technology!