Increasing the default number of PBKDF2 for existing accounts (2024)

FAQs

What is the recommended number of PBKDF2 iterations? ›

It's currently at 1000, but the recommended number by OWASP is now 600k for SHA-256 based PBKDF2 and 1300k for SHA1 - more on these numbers and whether they're appropriate later. The recommended number of iteration is regularly raised to match the improvement in hardware technology.

The public key cryptography standard recommends a salt length of at least 64 bits. The US National Institute of Standards and Technology recommends a salt length of at least 128 bits.

If you do 1,000 iterations of PBKDF2 then that will cut the attack down from 50 billion per second to 50 million per second. 10,000 iterations will be 5 million per second. A typical web server however will not be anywhere near that fast.

This option enables the use of PBKDF2 algorithm to derive the key. Use PBKDF2 algorithm with a default iteration count of 10000 unless otherwise specified by the -iter command line option. Set the salt length to use when using the -pbkdf2 option. For compatibility reasons, the default is 8 bytes.

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.

Fish flesh contains 75-80% water (fatty fish, 60-65 %), and during salting some of this water is removed and replaced by salt. A concentration of between 6–10 % salt in the fish tissue together with the drying effect due to loss of water will prevent the growth of most spoilage bacteria, and hence preventing a loss.

Ideally, the length of Salt should be as long as the output of the hash. For example, if the hash output is 32 bytes, the salt length should be at least 32 bytes, if not more. This step is an addition to passwords with specialized characters. Usernames must never be used as salt values.

Argon2id. Argon2, the winner of the 2015 Password Hashing Competition, is available as an alternative to PBKDF2 (learn more). There are three versions of the algorithm, and Bitwarden has implemented Argon2id as recommended by OWASP.

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.

How safe is PBKDF2? ›

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.

There is no optimal number of iterations. You should iterate until the error does not significantly decrease. To avoid overfitting, you should split the data set in training and test, and the error should be similar for both subsets.

The typical recommendation is to only use PBKDF2 if you must and instead use a newer password-based KDF if possible. However, various password managers still use PBKDF2 due to issues using Argon2 in JavaScript/browsers, although some are moving over. SHA-512 should be favoured because it requires fewer iterations.

Post-test loop: A post-test loop is a loop where the minimum number of itera- tions is 1. The loop body is always iterated at least once, and the condition is asked checked the first iteration. The condition determines if the loop body is to be iterated more than once.

Recommended minimum parameters

Memory: 46 MiB, Iterations: 1, Parallelism: 1. Memory: 19 MiB, Iterations: 2, Parallelism: 1. Memory: 12 MiB, Iterations: 3, Parallelism: 1.