mirror of
https://github.com/openssl/openssl.git
synced 2024-12-27 06:21:43 +08:00
fadb57e554
Replace "=for openssl foreign manuals" with simpler syntax, it looks like the "=for openssl ifdef" construct. Fix some broken L<> links; add some missing foreign references and fixed some typo's. The WARNINGS in dhparam referred to non-existant commands so reword it. Fixes #10109 Reviewed-by: Richard Levitte <levitte@openssl.org> Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org> (Merged from https://github.com/openssl/openssl/pull/10256)
110 lines
3.0 KiB
Plaintext
110 lines
3.0 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
EVP_PKEY_derive_init, EVP_PKEY_derive_set_peer, EVP_PKEY_derive
|
|
- derive public key algorithm shared secret
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/evp.h>
|
|
|
|
int EVP_PKEY_derive_init(EVP_PKEY_CTX *ctx);
|
|
int EVP_PKEY_derive_set_peer(EVP_PKEY_CTX *ctx, EVP_PKEY *peer);
|
|
int EVP_PKEY_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
EVP_PKEY_derive_init() initializes a public key algorithm context I<ctx> for
|
|
shared secret derivation using the algorithm given when the context was created
|
|
using L<EVP_PKEY_CTX_new(3)> or variants thereof. The algorithm is used to
|
|
fetch a B<EVP_KEYEXCH> method implicitly, see L<provider(7)/Implicit fetch> for
|
|
more information about implict fetches.
|
|
|
|
EVP_PKEY_derive_set_peer() sets the peer key: this will normally
|
|
be a public key.
|
|
|
|
EVP_PKEY_derive() derives a shared secret using I<ctx>.
|
|
If I<key> is NULL then the maximum size of the output buffer is written to the
|
|
I<keylen> parameter. If I<key> is not NULL then before the call the I<keylen>
|
|
parameter should contain the length of the I<key> buffer, if the call is
|
|
successful the shared secret is written to I<key> and the amount of data
|
|
written to I<keylen>.
|
|
|
|
=head1 NOTES
|
|
|
|
After the call to EVP_PKEY_derive_init(), algorithm
|
|
specific control operations can be performed to set any appropriate parameters
|
|
for the operation.
|
|
|
|
The function EVP_PKEY_derive() can be called more than once on the same
|
|
context if several operations are performed using the same parameters.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
EVP_PKEY_derive_init() and EVP_PKEY_derive() 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.
|
|
|
|
=head1 EXAMPLES
|
|
|
|
Derive shared secret (for example DH or EC keys):
|
|
|
|
#include <openssl/evp.h>
|
|
#include <openssl/rsa.h>
|
|
|
|
EVP_PKEY_CTX *ctx;
|
|
ENGINE *eng;
|
|
unsigned char *skey;
|
|
size_t skeylen;
|
|
EVP_PKEY *pkey, *peerkey;
|
|
/* NB: assumes pkey, eng, peerkey have been already set up */
|
|
|
|
ctx = EVP_PKEY_CTX_new(pkey, eng);
|
|
if (!ctx)
|
|
/* Error occurred */
|
|
if (EVP_PKEY_derive_init(ctx) <= 0)
|
|
/* Error */
|
|
if (EVP_PKEY_derive_set_peer(ctx, peerkey) <= 0)
|
|
/* Error */
|
|
|
|
/* Determine buffer length */
|
|
if (EVP_PKEY_derive(ctx, NULL, &skeylen) <= 0)
|
|
/* Error */
|
|
|
|
skey = OPENSSL_malloc(skeylen);
|
|
|
|
if (!skey)
|
|
/* malloc failure */
|
|
|
|
if (EVP_PKEY_derive(ctx, skey, &skeylen) <= 0)
|
|
/* Error */
|
|
|
|
/* Shared secret is skey bytes written to buffer skey */
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<EVP_PKEY_CTX_new(3)>,
|
|
L<EVP_PKEY_encrypt(3)>,
|
|
L<EVP_PKEY_decrypt(3)>,
|
|
L<EVP_PKEY_sign(3)>,
|
|
L<EVP_PKEY_verify(3)>,
|
|
L<EVP_PKEY_verify_recover(3)>,
|
|
L<EVP_KEYEXCH_fetch(3)>
|
|
|
|
=head1 HISTORY
|
|
|
|
These functions were added in OpenSSL 1.0.0.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2006-2018 The OpenSSL Project Authors. All Rights Reserved.
|
|
|
|
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
|
|
L<https://www.openssl.org/source/license.html>.
|
|
|
|
=cut
|