EVP_KDF-PBKDF2.7ossl - Man Page

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 SP800-132; it derives a key from a password using a salt and iteration count.

Identity

“PBKDF2” is the name for this implementation; it can be used with the EVP_KDF_fetch() function.

Supported parameters

The supported parameters are:

“pass” (OSSL_KDF_PARAM_PASSWORD) <octet string>
“salt” (OSSL_KDF_PARAM_SALT) <octet string>
“iter” (OSSL_KDF_PARAM_ITER) <unsigned integer>

This parameter has a default value of 2048.

“properties” (OSSL_KDF_PARAM_PROPERTIES) <UTF8 string>
“digest” (OSSL_KDF_PARAM_DIGEST) <UTF8 string>

These parameters work as described in “PARAMETERS” in EVP_KDF(3).

“pkcs5” (OSSL_KDF_PARAM_PKCS5) <integer>

This parameter can be used to enable or disable SP800-132 compliance checks. Setting the mode to 0 enables the compliance checks.

The checks performed are:

  • the iteration count is at least 1000.
  • the salt length is at least 128 bits.
  • the derived key length is at least 112 bits.

The default provider uses a default mode of 1 for backwards compatibility, and the fips provider uses a default mode of 0.

The value string is expected to be a decimal number 0 or 1.

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

SP800-132

See Also

EVP_KDF(3), EVP_KDF_CTX_new(3), EVP_KDF_CTX_free(3), EVP_KDF_CTX_set_params(3), EVP_KDF_derive(3), “PARAMETERS” in EVP_KDF(3)

History

This functionality was added to OpenSSL 3.0.

Referenced By

migration_guide.7ossl(7), openssl-kdf.1ossl(1), OSSL_PROVIDER-default.7ossl(7), OSSL_PROVIDER-FIPS.7ossl(7).

2021-09-09 3.0.0 OpenSSL