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.IX Title "EVP_KDF-HMAC-DRBG 7ssl"
.TH EVP_KDF-HMAC-DRBG 7ssl 2024-04-28 3.3.0 OpenSSL
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.SH NAME
EVP_KDF\-HMAC\-DRBG
\&\- The HMAC DRBG DETERMINISTIC EVP_KDF implementation
.SH DESCRIPTION
.IX Header "DESCRIPTION"
Support for a deterministic HMAC DRBG using the \fBEVP_KDF\fR API. This is similar
to \fBEVP_RAND\-HMAC\-DRBG\fR\|(7), but uses fixed values for its entropy and nonce
values. This is used to generate deterministic nonce value required by ECDSA
and DSA (as defined in RFC 6979).
.SS Identity
.IX Subsection "Identity"
"HMAC-DRBG-KDF" is the name for this implementation; it can be used
with the \fBEVP_KDF_fetch()\fR function.
.SS "Supported parameters"
.IX Subsection "Supported parameters"
The supported parameters are:
.IP """digest"" (\fBOSSL_DRBG_PARAM_DIGEST\fR) <UTF8 string>" 4
.IX Item """digest"" (OSSL_DRBG_PARAM_DIGEST) <UTF8 string>"
.PD 0
.IP """properties"" (\fBOSSL_DRBG_PARAM_PROPERTIES\fR) <UTF8 string>" 4
.IX Item """properties"" (OSSL_DRBG_PARAM_PROPERTIES) <UTF8 string>"
.PD
These parameters work as described in "PARAMETERS" in \fBEVP_KDF\fR\|(3).
.IP """entropy"" (\fBOSSL_KDF_PARAM_HMACDRBG_ENTROPY\fR) <octet string>" 4
.IX Item """entropy"" (OSSL_KDF_PARAM_HMACDRBG_ENTROPY) <octet string>"
Sets the entropy bytes supplied to the HMAC-DRBG.
.IP """nonce"" (\fBOSSL_KDF_PARAM_HMACDRBG_NONCE\fR) <octet string>" 4
.IX Item """nonce"" (OSSL_KDF_PARAM_HMACDRBG_NONCE) <octet string>"
Sets the nonce bytes supplied to the HMAC-DRBG.
.SH NOTES
.IX Header "NOTES"
A context for KDF HMAC DRBG can be obtained by calling:
.PP
.Vb 2
\& EVP_KDF *kdf = EVP_KDF_fetch(NULL, "HMAC\-DRBG\-KDF", NULL);
\& EVP_KDF_CTX *kdf_ctx = EVP_KDF_CTX_new(kdf, NULL);
.Ve
.SH "CONFORMING TO"
.IX Header "CONFORMING TO"
RFC 6979
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBEVP_KDF\fR\|(3),
"PARAMETERS" in \fBEVP_KDF\fR\|(3)
.SH HISTORY
.IX Header "HISTORY"
The EVP_KDF\-HMAC\-DRBG functionality was added in OpenSSL 3.2.
.SH COPYRIGHT
.IX Header "COPYRIGHT"
Copyright 2022\-2023 The OpenSSL Project Authors. All Rights Reserved.
.PP
Licensed under the Apache License 2.0 (the "License").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file LICENSE in the source distribution or at
<https://www.openssl.org/source/license.html>.