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Diffstat (limited to 'static/freebsd/man3/EVP_PKEY_CTX_set_hkdf_md.3')
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diff --git a/static/freebsd/man3/EVP_PKEY_CTX_set_hkdf_md.3 b/static/freebsd/man3/EVP_PKEY_CTX_set_hkdf_md.3 new file mode 100644 index 00000000..331e81fa --- /dev/null +++ b/static/freebsd/man3/EVP_PKEY_CTX_set_hkdf_md.3 @@ -0,0 +1,218 @@ +.\" -*- mode: troff; coding: utf-8 -*- +.\" Automatically generated by Pod::Man v6.0.2 (Pod::Simple 3.45) +.\" +.\" Standard preamble: +.\" ======================================================================== +.de Sp \" Vertical space (when we can't use .PP) +.if t .sp .5v +.if n .sp +.. +.de Vb \" Begin verbatim text +.ft CW +.nf +.ne \\$1 +.. +.de Ve \" End verbatim text +.ft R +.fi +.. +.\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>. +.ie n \{\ +. ds C` "" +. ds C' "" +'br\} +.el\{\ +. ds C` +. ds C' +'br\} +.\" +.\" Escape single quotes in literal strings from groff's Unicode transform. +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" +.\" If the F register is >0, we'll generate index entries on stderr for +.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index +.\" entries marked with X<> in POD. Of course, you'll have to process the +.\" output yourself in some meaningful fashion. +.\" +.\" Avoid warning from groff about undefined register 'F'. +.de IX +.. +.nr rF 0 +.if \n(.g .if rF .nr rF 1 +.if (\n(rF:(\n(.g==0)) \{\ +. if \nF \{\ +. de IX +. tm Index:\\$1\t\\n%\t"\\$2" +.. +. if !\nF==2 \{\ +. nr % 0 +. nr F 2 +. \} +. \} +.\} +.rr rF +.\" +.\" Required to disable full justification in groff 1.23.0. +.if n .ds AD l +.\" ======================================================================== +.\" +.IX Title "EVP_PKEY_CTX_SET_HKDF_MD 3ossl" +.TH EVP_PKEY_CTX_SET_HKDF_MD 3ossl 2026-04-07 3.5.6 OpenSSL +.\" For nroff, turn off justification. Always turn off hyphenation; it makes +.\" way too many mistakes in technical documents. +.if n .ad l +.nh +.SH NAME +EVP_PKEY_CTX_set_hkdf_md, EVP_PKEY_CTX_set1_hkdf_salt, +EVP_PKEY_CTX_set1_hkdf_key, EVP_PKEY_CTX_add1_hkdf_info, +EVP_PKEY_CTX_set_hkdf_mode \- +HMAC\-based Extract\-and\-Expand key derivation algorithm +.SH SYNOPSIS +.IX Header "SYNOPSIS" +.Vb 1 +\& #include <openssl/kdf.h> +\& +\& int EVP_PKEY_CTX_set_hkdf_mode(EVP_PKEY_CTX *pctx, int mode); +\& +\& int EVP_PKEY_CTX_set_hkdf_md(EVP_PKEY_CTX *pctx, const EVP_MD *md); +\& +\& int EVP_PKEY_CTX_set1_hkdf_salt(EVP_PKEY_CTX *pctx, unsigned char *salt, +\& int saltlen); +\& +\& int EVP_PKEY_CTX_set1_hkdf_key(EVP_PKEY_CTX *pctx, unsigned char *key, +\& int keylen); +\& +\& int EVP_PKEY_CTX_add1_hkdf_info(EVP_PKEY_CTX *pctx, unsigned char *info, +\& int infolen); +.Ve +.SH DESCRIPTION +.IX Header "DESCRIPTION" +The EVP_PKEY_HKDF algorithm implements the HKDF key derivation function. +HKDF follows the "extract\-then\-expand" paradigm, where the KDF logically +consists of two modules. The first stage takes the input keying material +and "extracts" from it a fixed\-length pseudorandom key K. The second stage +"expands" the key K into several additional pseudorandom keys (the output +of the KDF). +.PP +\&\fBEVP_PKEY_CTX_set_hkdf_mode()\fR sets the mode for the HKDF operation. There +are three modes that are currently defined: +.IP EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND 4 +.IX Item "EVP_PKEY_HKDEF_MODE_EXTRACT_AND_EXPAND" +This is the default mode. Calling \fBEVP_PKEY_derive\fR\|(3) on an EVP_PKEY_CTX set +up for HKDF will perform an extract followed by an expand operation in one go. +The derived key returned will be the result after the expand operation. The +intermediate fixed\-length pseudorandom key K is not returned. +.Sp +In this mode the digest, key, salt and info values must be set before a key is +derived or an error occurs. +.IP EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY 4 +.IX Item "EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY" +In this mode calling \fBEVP_PKEY_derive\fR\|(3) will just perform the extract +operation. The value returned will be the intermediate fixed\-length pseudorandom +key K. +.Sp +The digest, key and salt values must be set before a key is derived or an +error occurs. +.IP EVP_PKEY_HKDEF_MODE_EXPAND_ONLY 4 +.IX Item "EVP_PKEY_HKDEF_MODE_EXPAND_ONLY" +In this mode calling \fBEVP_PKEY_derive\fR\|(3) will just perform the expand +operation. The input key should be set to the intermediate fixed\-length +pseudorandom key K returned from a previous extract operation. +.Sp +The digest, key and info values must be set before a key is derived or an +error occurs. +.PP +\&\fBEVP_PKEY_CTX_set_hkdf_md()\fR sets the message digest associated with the HKDF. +.PP +\&\fBEVP_PKEY_CTX_set1_hkdf_salt()\fR sets the salt to \fBsaltlen\fR bytes of the +buffer \fBsalt\fR. Any existing value is replaced. +.PP +\&\fBEVP_PKEY_CTX_set1_hkdf_key()\fR sets the key to \fBkeylen\fR bytes of the buffer +\&\fBkey\fR. Any existing value is replaced. +.PP +\&\fBEVP_PKEY_CTX_add1_hkdf_info()\fR sets the info value to \fBinfolen\fR bytes of the +buffer \fBinfo\fR. If a value is already set, it is appended to the existing +value. +.SH "STRING CTRLS" +.IX Header "STRING CTRLS" +HKDF also supports string based control operations via +\&\fBEVP_PKEY_CTX_ctrl_str\fR\|(3). +The \fBtype\fR parameter "md" uses the supplied \fBvalue\fR as the name of the digest +algorithm to use. +The \fBtype\fR parameter "mode" uses the values "EXTRACT_AND_EXPAND", +"EXTRACT_ONLY" and "EXPAND_ONLY" to determine the mode to use. +The \fBtype\fR parameters "salt", "key" and "info" use the supplied \fBvalue\fR +parameter as a \fBseed\fR, \fBkey\fR or \fBinfo\fR value. +The names "hexsalt", "hexkey" and "hexinfo" are similar except they take a hex +string which is converted to binary. +.SH NOTES +.IX Header "NOTES" +A context for HKDF can be obtained by calling: +.PP +.Vb 1 +\& EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL); +.Ve +.PP +The total length of the info buffer cannot exceed 2048 bytes in length: this +should be more than enough for any normal use of HKDF. +.PP +The output length of an HKDF expand operation is specified via the length +parameter to the \fBEVP_PKEY_derive\fR\|(3) function. +Since the HKDF output length is variable, passing a \fBNULL\fR buffer as a means +to obtain the requisite length is not meaningful with HKDF in any mode that +performs an expand operation. Instead, the caller must allocate a buffer of the +desired length, and pass that buffer to \fBEVP_PKEY_derive\fR\|(3) along with (a +pointer initialized to) the desired length. Passing a \fBNULL\fR buffer to obtain +the length is allowed when using EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY. +.PP +Optimised versions of HKDF can be implemented in an ENGINE. +.SH "RETURN VALUES" +.IX Header "RETURN VALUES" +All these functions return 1 for success and 0 or a negative value for failure. +In particular a return value of \-2 indicates the operation is not supported by +the public key algorithm. +.SH EXAMPLES +.IX Header "EXAMPLES" +This example derives 10 bytes using SHA\-256 with the secret key "secret", +salt value "salt" and info value "label": +.PP +.Vb 4 +\& EVP_PKEY_CTX *pctx; +\& unsigned char out[10]; +\& size_t outlen = sizeof(out); +\& pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL); +\& +\& if (EVP_PKEY_derive_init(pctx) <= 0) +\& /* Error */ +\& if (EVP_PKEY_CTX_set_hkdf_md(pctx, EVP_sha256()) <= 0) +\& /* Error */ +\& if (EVP_PKEY_CTX_set1_hkdf_salt(pctx, "salt", 4) <= 0) +\& /* Error */ +\& if (EVP_PKEY_CTX_set1_hkdf_key(pctx, "secret", 6) <= 0) +\& /* Error */ +\& if (EVP_PKEY_CTX_add1_hkdf_info(pctx, "label", 5) <= 0) +\& /* Error */ +\& if (EVP_PKEY_derive(pctx, out, &outlen) <= 0) +\& /* Error */ +.Ve +.SH "CONFORMING TO" +.IX Header "CONFORMING TO" +RFC 5869 +.SH "SEE ALSO" +.IX Header "SEE ALSO" +\&\fBEVP_PKEY_CTX_new\fR\|(3), +\&\fBEVP_PKEY_CTX_ctrl_str\fR\|(3), +\&\fBEVP_PKEY_derive\fR\|(3) +.SH HISTORY +.IX Header "HISTORY" +All of the functions described here were converted from macros to functions in +OpenSSL 3.0. +.SH COPYRIGHT +.IX Header "COPYRIGHT" +Copyright 2016\-2021 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>. |