The error “data and salt arguments required” occurs when using the hashlib library in Python, specifically when calling the hashlib.pbkdf2_hmac() method. This error message is raised when the required arguments data and salt are not provided to the method.
The hashlib.pbkdf2_hmac() method is used to derive a cryptographic key from a given password and salt using the PBKDF2 algorithm. It provides an additional layer of security by applying a computationally expensive hashing process multiple times.
Example:
Let’s take a look at an example of how to use the hashlib.pbkdf2_hmac() method correctly:
import hashlib
password = "mypassword".encode('utf-8')
salt = b'somesalt'
key = hashlib.pbkdf2_hmac('sha256', password, salt, 100000)
print(key.hex())
In this example, we first convert the password to bytes using the encode() method. We also define a salt as bytes. Then, we pass the hash algorithm ‘sha256’, password, salt, and the number of iterations to the hashlib.pbkdf2_hmac() method.
The method will return the derived key as bytes. In this example, we convert it to hexadecimal format using the hex() method and print it.
Make sure to provide the correct password and a unique salt value for each user to enhance security and prevent common attacks like rainbow table attacks.