What is PBKDF2? (2024)

FAQs

Is PBKDF2 recommended? ›

PBKDF2. Since PBKDF2 is recommended by NIST and has FIPS-140 validated implementations, so it should be the preferred algorithm when these are required. The PBKDF2 algorithm requires that you select an internal hashing algorithm such as an HMAC or a variety of other hashing algorithms.

In cryptography, PBKDF1 and PBKDF2 (Password-Based Key Derivation Function 1 and 2) are key derivation functions with a sliding computational cost, used to reduce vulnerability to brute-force attacks. PBKDF2 is part of RSA Laboratories' Public-Key Cryptography Standards (PKCS) series, specifically PKCS #5 v2.

In this section we present some weaknesses of PBKDF2. The major one concerns the precomputation of specific values that can be reused during the key derivation process. The others aim to avoid useless operations during the computation of the hash function.

The current recommendation from OWASP [5] is to use an iteration count of 600,000 for PBKDF2 with SHA-256 and an iteration count of 1,300,000 for PBKDF2 with SHA-1. In addition to AES-GCM and AES-CCM, we suggest to also add a reference to SP 800-38F [7] that defines AES-KW and AES-KWP.

PBKDF2 is simple to implement but is considered to be less secure than more advanced algorithms. Bcrypt is more secure but is more resource-intensive. Scrypt is the most secure but is also the most resource-intensive.

While PBKDF2 is a secure choice for key derivation, modern alternatives like bcrypt and scrypt offer advantages in specific contexts.

You cannot really reverse PBKDF2, and guessing the value of the previous iteration round (256 bits) is even with merely one iteration way harder than guessing the password (<100 bits) at 100k iterations.

Enhanced Security Against Brute-Force Attacks: By making the hash computation slow and resource-intensive, PBKDF2 significantly reduces the risk of brute-force attacks.

Learn more about the key derivation process in the 1Password Security Design White Paper . There are 650,000 iterations, or functions, of PBKDF2 in the current version of 1Password. This means anyone who tries to guess an account password needs to perform the same calculations.

There are two related reasons for using a password-based key derivation function like PBKDF2. One is to protect password hashes used for login on a website. The other is to derive a cryptographic key from a password to use for encryption.

Can you decrypt PBKDF2? ›

As its very name implies, PBKDF is a KDF, a key derivation function. It's a hash function – it doesn't encrypt anything, and it's not (realistically) invertible.

PBKDF2 (Password-Based Key Derivation Function 2) is a widely used method of protecting passwords. A key derivation function such as PBKDF2 is designed to make it more difficult for an attacker to crack a password, even if they possess the hashed password value.

PBKDF2 Calculation in Python - Example

The PBKDF2 calculation function takes several input parameters: hash function for the HMAC, the password (bytes sequence), the salt (bytes sequence), iterations count and the output key length (number of bytes for the derived key).

PBKDF2 algorithm is used in simplemembership provider(universalprovider) 2.0 is a Non- FIPS Complaint Algorithm.

Another important detail is that SHA256 hashes don't include the salt element, which makes them more susceptible to dictionary-based cyberattacks. So while SHA256 is more suitable for applications that require frequent interaction, bcrypt is a better solution for safely storing passwords.

The Advantages of Using PBKDF2

Enhanced Security Against Brute-Force Attacks: By making the hash computation slow and resource-intensive, PBKDF2 significantly reduces the risk of brute-force attacks.

In short, argon2 is better. Do beware that iOS auto-fill still seems to cause some issues, so if you use iOS, lower your “memory” setting to 48 MiB. More technical explanation: Argon2 was specifically crafted to fix the inherent flaws of compute bounded key derivation functions like pbkdf2.

Choosing a slow algorithm is actually preferred for password hashing. Of the hashing schemes provided, only PBKDF2 and Bcrypt are designed to be slow which makes them the best choice for password hashing, MD5 and SHA-256 were designed to be fast and as such this makes them a less than ideal choice.

To protect passwords, experts suggest using a strong and slow hashing algorithm like Argon2 or Bcrypt, combined with salt (or even better, with salt and pepper). (Basically, avoid faster algorithms for this usage.) To verify file signatures and certificates, SHA-256 is among your best hashing algorithm choices.