mirror of
https://github.com/openssl/openssl.git
synced 2024-12-27 06:21:43 +08:00
112 lines
3.6 KiB
Plaintext
112 lines
3.6 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
EVP_PKEY_decapsulate_init, EVP_PKEY_auth_decapsulate_init, EVP_PKEY_decapsulate
|
|
- Key decapsulation using a KEM algorithm with a private key
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/evp.h>
|
|
|
|
int EVP_PKEY_decapsulate_init(EVP_PKEY_CTX *ctx, const OSSL_PARAM params[]);
|
|
int EVP_PKEY_auth_decapsulate_init(EVP_PKEY_CTX *ctx, EVP_PKEY *authpub,
|
|
const OSSL_PARAM params[]);
|
|
int EVP_PKEY_decapsulate(EVP_PKEY_CTX *ctx,
|
|
unsigned char *unwrapped, size_t *unwrappedlen,
|
|
const unsigned char *wrapped, size_t wrappedlen);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
The EVP_PKEY_decapsulate_init() function initializes a private key algorithm
|
|
context I<ctx> for a decapsulation operation and then sets the I<params>
|
|
on the context in the same way as calling L<EVP_PKEY_CTX_set_params(3)>.
|
|
Note that I<ctx> usually is produced using L<EVP_PKEY_CTX_new_from_pkey(3)>,
|
|
specifying the private key to use.
|
|
|
|
The EVP_PKEY_auth_decapsulate_init() function is similar to
|
|
EVP_PKEY_decapsulate_init() but also passes an I<authpub> authentication public
|
|
key that is used during decapsulation.
|
|
|
|
The EVP_PKEY_decapsulate() function performs a private key decapsulation
|
|
operation using I<ctx>. The data to be decapsulated is specified using the
|
|
I<wrapped> and I<wrappedlen> parameters.
|
|
If I<unwrapped> is NULL then the maximum size of the output secret buffer
|
|
is written to I<*unwrappedlen>. If I<unwrapped> is not NULL and the
|
|
call is successful then the decapsulated secret data is written to I<unwrapped>
|
|
and the amount of data written to I<*unwrappedlen>.
|
|
|
|
=head1 NOTES
|
|
|
|
After the call to EVP_PKEY_decapsulate_init() algorithm-specific parameters
|
|
for the operation may be set or modified using L<EVP_PKEY_CTX_set_params(3)>.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
EVP_PKEY_decapsulate_init(), EVP_PKEY_auth_decapsulate_init() and
|
|
EVP_PKEY_decapsulate() 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 private key algorithm.
|
|
|
|
=head1 EXAMPLES
|
|
|
|
Decapsulate data using RSA:
|
|
|
|
#include <openssl/evp.h>
|
|
|
|
/*
|
|
* NB: assumes rsa_priv_key is an RSA private key,
|
|
* and that in, inlen are already set up to contain encapsulated data.
|
|
*/
|
|
|
|
EVP_PKEY_CTX *ctx = NULL;
|
|
size_t secretlen = 0;
|
|
unsigned char *secret = NULL;;
|
|
|
|
ctx = EVP_PKEY_CTX_new_from_pkey(libctx, rsa_priv_key, NULL);
|
|
if (ctx = NULL)
|
|
/* Error */
|
|
if (EVP_PKEY_decapsulate_init(ctx, NULL) <= 0)
|
|
/* Error */
|
|
|
|
/* Set the mode - only 'RSASVE' is currently supported */
|
|
if (EVP_PKEY_CTX_set_kem_op(ctx, "RSASVE") <= 0)
|
|
/* Error */
|
|
|
|
/* Determine buffer length */
|
|
if (EVP_PKEY_decapsulate(ctx, NULL, &secretlen, in, inlen) <= 0)
|
|
/* Error */
|
|
|
|
secret = OPENSSL_malloc(secretlen);
|
|
if (secret == NULL)
|
|
/* malloc failure */
|
|
|
|
/* Decapsulated secret data is secretlen bytes long */
|
|
if (EVP_PKEY_decapsulate(ctx, secret, &secretlen, in, inlen) <= 0)
|
|
/* Error */
|
|
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<EVP_PKEY_CTX_new_from_pkey(3)>,
|
|
L<EVP_PKEY_encapsulate(3)>,
|
|
L<EVP_KEM-RSA(7)>, L<EVP_KEM-X25519(7)>, L<EVP_KEM-EC(7)>
|
|
|
|
=head1 HISTORY
|
|
|
|
The functions EVP_PKEY_decapsulate_init() and EVP_PKEY_decapsulate() were added
|
|
in OpenSSL 3.0.
|
|
|
|
The function EVP_PKEY_auth_decapsulate_init() was added in OpenSSL 3.2.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2020-2023 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
|