Definition

A key derivation function is a cryptographic algorithm that derives secret keys from an initial input, such as a master key, password, or passphrase. It aims to enhance key security by making them longer, more random, and harder-to-guess values.

The derivation process transforms the initial key or password using cryptographic methods like salting, hashing, or stretching. This adds randomness and complexity to the derived key, making it resistant to dictionary attacks and brute force.

KDF is used in many cryptographic applications. For example, it is used in password-based key derivation to create a cryptographic key based on a user’s password. This can give the derived key a higher entropy than the original password, minimizing the risk of successful attacks.

Many parties use KDFs in various agreement protocols to generate a shared secret key. In this case, each participant independently generates the same key from their respective inputs, guaranteeing that the shared key is identical across all parties.

Key Derivation Function Application