KDF

Jan 1, 0001

Definition

A Key Derivation Function (KDF) is a cryptographic algorithm designed to derive one or more secret keys from a secret value, such as a password or a master key. KDFs are used to enhance security by adding computational complexity and randomness, making it difficult for attackers to derive the original secret. They are commonly used in password hashing, secure key exchange protocols, and encryption schemes to ensure that derived keys are strong and resistant to brute-force attacks.

Secure Settings Example

import hashlib
import os
from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC
from cryptography.hazmat.primitives import hashes

# Secure KDF configuration using PBKDF2
password = b"secure_password"
salt = os.urandom(16)  # Securely generated random salt
kdf = PBKDF2HMAC(
    algorithm=hashes.SHA256(),
    length=32,
    salt=salt,
    iterations=100000,  # High iteration count for security
)
key = kdf.derive(password)

Insecure Settings Example

import hashlib

# Insecure KDF configuration using a low iteration count
password = b"weak_password"
salt = b"static_salt"  # Static salt, not secure
kdf = hashlib.pbkdf2_hmac(
    'sha256',
    password,
    salt,
    1000  # Low iteration count, vulnerable to brute-force attacks
)