xref: /openssl/doc/man7/EVP_KDF-HMAC-DRBG.pod (revision da1c088f)
1=pod
2
3=head1 NAME
4
5EVP_KDF-HMAC-DRBG
6- The HMAC DRBG DETERMINISTIC EVP_KDF implementation
7
8=head1 DESCRIPTION
9
10Support for a deterministic HMAC DRBG using the B<EVP_KDF> API. This is similar
11to L<EVP_RAND-HMAC-DRBG(7)>, but uses fixed values for its entropy and nonce
12values. This is used to generate deterministic nonce value required by ECDSA
13and DSA (as defined in RFC 6979).
14
15=head2 Identity
16
17"HMAC-DRBG-KDF" is the name for this implementation; it can be used
18with the EVP_KDF_fetch() function.
19
20=head2 Supported parameters
21
22The supported parameters are:
23
24=over 4
25
26=item "digest" (B<OSSL_DRBG_PARAM_DIGEST>) <UTF8 string>
27
28=item "properties" (B<OSSL_DRBG_PARAM_PROPERTIES>) <UTF8 string>
29
30These parameters work as described in L<EVP_KDF(3)/PARAMETERS>.
31
32=item "entropy" (B<OSSL_KDF_PARAM_HMACDRBG_ENTROPY>) <octet string>
33
34Sets the entropy bytes supplied to the HMAC-DRBG.
35
36=item "nonce" (B<OSSL_KDF_PARAM_HMACDRBG_NONCE>) <octet string>
37
38Sets the nonce bytes supplied to the HMAC-DRBG.
39
40=back
41
42=head1 NOTES
43
44A context for KDF HMAC DRBG can be obtained by calling:
45
46 EVP_KDF *kdf = EVP_KDF_fetch(NULL, "HMAC-DRBG-KDF", NULL);
47 EVP_KDF_CTX *kdf_ctx = EVP_KDF_CTX_new(kdf, NULL);
48
49=head1 CONFORMING TO
50
51RFC 6979
52
53=head1 SEE ALSO
54
55L<EVP_KDF(3)>,
56L<EVP_KDF(3)/PARAMETERS>
57
58=head1 HISTORY
59
60The EVP_KDF-HMAC-DRBG functionality was added in OpenSSL 3.2.
61
62=head1 COPYRIGHT
63
64Copyright 2022-2023 The OpenSSL Project Authors. All Rights Reserved.
65
66Licensed under the Apache License 2.0 (the "License").  You may not use
67this file except in compliance with the License.  You can obtain a copy
68in the file LICENSE in the source distribution or at
69L<https://www.openssl.org/source/license.html>.
70
71=cut
72