Key Derivation Functions
Key Derivation Functions (KDFs) are cryptographic algorithms designed to derive one or more secret keys from a secret value, such as a password, master key, or other input. They are essential for securely generating cryptographic keys for encryption, authentication, and other security purposes, often incorporating salting and iteration to enhance resistance against brute-force attacks. Common examples include PBKDF2, bcrypt, scrypt, and Argon2, each with varying trade-offs in security, performance, and resource usage.
Developers should learn and use KDFs when handling sensitive data like user passwords, encryption keys, or secure communication channels, as they provide a standardized way to strengthen weak inputs against attacks. For instance, in web applications, KDFs like PBKDF2 or Argon2 are used to hash passwords before storage, preventing plaintext exposure and mitigating risks from data breaches. They are also crucial in cryptographic protocols for key agreement and derivation in systems like TLS or VPNs.