| 1 | =pod
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| 2 |
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| 3 | =head1 NAME
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| 4 |
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| 5 | EVP_KDF-PBKDF2 - The PBKDF2 EVP_KDF implementation
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| 6 |
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| 7 | =head1 DESCRIPTION
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| 8 |
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| 9 | Support for computing the B<PBKDF2> password-based KDF through the B<EVP_KDF>
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| 10 | API.
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| 11 |
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| 12 | The EVP_KDF-PBKDF2 algorithm implements the PBKDF2 password-based key
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| 13 | derivation function, as described in SP800-132; it derives a key from a password
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| 14 | using a salt and iteration count.
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| 15 |
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| 16 | The output is considered to be a cryptographic key.
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| 17 |
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| 18 | =head2 Identity
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| 19 |
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| 20 | "PBKDF2" is the name for this implementation; it
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| 21 | can be used with the EVP_KDF_fetch() function.
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| 22 |
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| 23 | =head2 Supported parameters
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| 24 |
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| 25 | The supported parameters are:
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| 26 |
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| 27 | =over 4
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| 28 |
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| 29 | =item "pass" (B<OSSL_KDF_PARAM_PASSWORD>) <octet string>
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| 30 |
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| 31 | =item "salt" (B<OSSL_KDF_PARAM_SALT>) <octet string>
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| 32 |
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| 33 | =item "iter" (B<OSSL_KDF_PARAM_ITER>) <unsigned integer>
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| 34 |
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| 35 | This parameter has a default value of 2048.
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| 36 |
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| 37 | =item "properties" (B<OSSL_KDF_PARAM_PROPERTIES>) <UTF8 string>
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| 38 |
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| 39 | =item "digest" (B<OSSL_KDF_PARAM_DIGEST>) <UTF8 string>
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| 40 |
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| 41 | These parameters work as described in L<EVP_KDF(3)/PARAMETERS>.
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| 42 |
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| 43 | =item "pkcs5" (B<OSSL_KDF_PARAM_PKCS5>) <integer>
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| 44 |
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| 45 | This parameter can be used to enable or disable SP800-132 compliance checks.
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| 46 | Setting the mode to 0 enables the compliance checks.
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| 47 |
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| 48 | The checks performed are:
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| 49 |
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| 50 | =over 4
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| 51 |
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| 52 | =item - the iteration count is at least 1000.
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| 53 |
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| 54 | =item - the salt length is at least 128 bits.
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| 55 |
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| 56 | =item - the derived key length is at least 112 bits.
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| 57 |
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| 58 | =back
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| 59 |
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| 60 | The default provider uses a default mode of 1 for backwards compatibility,
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| 61 | and the FIPS provider uses a default mode of 0.
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| 62 | This option breaks FIPS compliance if it causes the approved "fips-indicator"
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| 63 | to return 0.
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| 64 |
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| 65 | =item "fips-indicator" (B<OSSL_KDF_PARAM_FIPS_APPROVED_INDICATOR>) <integer>
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| 66 |
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| 67 | This option is used by the OpenSSL FIPS provider.
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| 68 |
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| 69 | A getter that returns 1 if the operation is FIPS approved, or 0 otherwise.
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| 70 | This may be used after calling EVP_KDF_derive. It returns 0 if "pkcs5"
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| 71 | is set to 1 and the derived key length, salt length or iteration count test
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| 72 | fails.
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| 73 |
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| 74 | =back
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| 75 |
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| 76 | =head1 NOTES
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| 77 |
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| 78 | A typical application of this algorithm is to derive keying material for an
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| 79 | encryption algorithm from a password in the "pass", a salt in "salt",
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| 80 | and an iteration count.
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| 81 |
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| 82 | Increasing the "iter" parameter slows down the algorithm which makes it
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| 83 | harder for an attacker to perform a brute force attack using a large number
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| 84 | of candidate passwords.
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| 85 |
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| 86 | No assumption is made regarding the given password; it is simply treated as a
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| 87 | byte sequence.
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| 88 |
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| 89 | =head1 CONFORMING TO
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| 90 |
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| 91 | SP800-132
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| 92 |
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| 93 | =head1 SEE ALSO
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| 94 |
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| 95 | L<EVP_KDF(3)>,
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| 96 | L<EVP_KDF_CTX_new(3)>,
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| 97 | L<EVP_KDF_CTX_free(3)>,
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| 98 | L<EVP_KDF_CTX_set_params(3)>,
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| 99 | L<EVP_KDF_derive(3)>,
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| 100 | L<EVP_KDF(3)/PARAMETERS>
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| 101 |
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| 102 | =head1 HISTORY
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| 103 |
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| 104 | This functionality was added in OpenSSL 3.0.
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| 105 |
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| 106 | =head1 COPYRIGHT
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| 107 |
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| 108 | Copyright 2018-2024 The OpenSSL Project Authors. All Rights Reserved.
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| 109 |
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| 110 | Licensed under the Apache License 2.0 (the "License"). You may not use
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| 111 | this file except in compliance with the License. You can obtain a copy
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| 112 | in the file LICENSE in the source distribution or at
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| 113 | L<https://www.openssl.org/source/license.html>.
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| 114 |
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| 115 | =cut
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