EVP_KDF_PBKDF2.7ssl man page

EVP_KDF_PBKDF2 — The PBKDF2 EVP_KDF implementation

Description

Support for computing the PBKDF2 password-based KDF through the EVP_KDF API.

The EVP_KDF_PBKDF2 algorithm implements the PBKDF2 password-based key derivation function, as described in RFC 2898; it derives a key from a password using a salt and iteration count.

Numeric identity

EVP_KDF_PBKDF2 is the numeric identity for this implementation; it can be used with the EVP_KDF_CTX_new_id() function.

Supported controls

The supported controls are:

EVP_KDF_CTRL_SET_PASS
EVP_KDF_CTRL_SET_SALT
EVP_KDF_CTRL_SET_ITER
EVP_KDF_CTRL_SET_MD

These controls work as described in “CONTROLS” in EVP_KDF_CTX(3).

iter is the iteration count and its value should be greater than or equal to 1. RFC 2898 suggests an iteration count of at least 1000.  The default value is 2048.  Any iter less than 1 is treated as a single iteration.

Notes

A typical application of this algorithm is to derive keying material for an encryption algorithm from a password in the pass, a salt in salt, and an iteration count.

Increasing the iter parameter slows down the algorithm which makes it harder for an attacker to perform a brute force attack using a large number of candidate passwords.

No assumption is made regarding the given password; it is simply treated as a byte sequence.

Conforming to

RFC 2898

See Also

EVP_KDF_CTX, EVP_KDF_CTX_new_id(3), EVP_KDF_CTX_free(3), EVP_KDF_ctrl(3), EVP_KDF_derive(3), “CONTROLS” in EVP_KDF_CTX(3)

Info

2019-07-25 1.1.1c OpenSSL