f0efeea29e
The existing code used PKCS5 specifications. SP800-132 adds the following additional constraints for: - the range of the key length. - the minimum iteration count (1000 recommended). - salt length (at least 128 bits). These additional constraints may cause errors (in scrypt, and some PKCS5 related test vectors). To disable the new constraints use the new ctrl string "pkcs5". For backwards compatability, the checks are only enabled by default for fips mode. Reviewed-by: Matt Caswell <matt@openssl.org> (Merged from https://github.com/openssl/openssl/pull/8868)
107 lines
2.4 KiB
Text
107 lines
2.4 KiB
Text
=pod
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=head1 NAME
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EVP_KDF_PBKDF2 - The PBKDF2 EVP_KDF implementation
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=head1 DESCRIPTION
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Support for computing the B<PBKDF2> password-based KDF through the B<EVP_KDF>
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API.
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The EVP_KDF_PBKDF2 algorithm implements the PBKDF2 password-based key
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derivation function, as described in SP800-132; it derives a key from a password
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using a salt and iteration count.
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=head2 Numeric identity
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B<EVP_KDF_PBKDF2> is the numeric identity for this implementation; it
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can be used with the EVP_KDF_CTX_new_id() function.
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=head2 Supported controls
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The supported controls are:
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=over 4
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=item B<EVP_KDF_CTRL_SET_PASS>
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=item B<EVP_KDF_CTRL_SET_SALT>
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=item B<EVP_KDF_CTRL_SET_ITER>
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This control has a default value of 2048.
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=item B<EVP_KDF_CTRL_SET_MD>
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These controls work as described in L<EVP_KDF_CTX(3)/CONTROLS>.
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=item B<EVP_KDF_CTRL_SET_PBKDF2_PKCS5_MODE>
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This control expects one argument: C<int mode>
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This control can be used to enable or disable SP800-132 compliance checks.
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Setting the mode to 0 enables the compliance checks.
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The checks performed are:
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=over 4
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=item - the iteration count is at least 1000.
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=item - the salt length is at least 128 bits.
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=item - the derived key length is at least 112 bits.
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=back
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The default provider uses a default mode of 1 for backwards compatibility,
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and the fips provider uses a default mode of 0.
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EVP_KDF_ctrl_str() type string: "pkcs5"
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The value string is expected to be a decimal number 0 or 1.
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=back
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=head1 NOTES
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A typical application of this algorithm is to derive keying material for an
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encryption algorithm from a password in the B<pass>, a salt in B<salt>,
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and an iteration count.
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Increasing the B<iter> parameter slows down the algorithm which makes it
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harder for an attacker to perform a brute force attack using a large number
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of candidate passwords.
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No assumption is made regarding the given password; it is simply treated as a
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byte sequence.
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=head1 CONFORMING TO
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SP800-132
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=head1 SEE ALSO
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L<EVP_KDF_CTX>,
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L<EVP_KDF_CTX_new_id(3)>,
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L<EVP_KDF_CTX_free(3)>,
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L<EVP_KDF_ctrl(3)>,
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L<EVP_KDF_derive(3)>,
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L<EVP_KDF_CTX(3)/CONTROLS>
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=head1 HISTORY
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This functionality was added to OpenSSL 3.0.0.
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=head1 COPYRIGHT
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Copyright 2018-2019 The OpenSSL Project Authors. All Rights Reserved.
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Licensed under the Apache License 2.0 (the "License"). You may not use
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this file except in compliance with the License. You can obtain a copy
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in the file LICENSE in the source distribution or at
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L<https://www.openssl.org/source/license.html>.
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=cut
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