EVP_PKEY_gettable_params, EVP_PKEY_get_int_param, EVP_PKEY_get_size_t_param, EVP_PKEY_get_bn_param, EVP_PKEY_get_utf8_string_param, EVP_PKEY_get_octet_string_param - retrieve key parameters from a key
#include <openssl/evp.h>
const OSSL_PARAM *EVP_PKEY_gettable_params(EVP_PKEY *pkey);
int EVP_PKEY_get_int_param(EVP_PKEY *pkey, const char *key_name, int *out);
int EVP_PKEY_get_size_t_param(EVP_PKEY *pkey, const char *key_name, size_t *out);
int EVP_PKEY_get_bn_param(EVP_PKEY *pkey, const char *key_name, BIGNUM **bn);
int EVP_PKEY_get_utf8_string_param(EVP_PKEY *pkey, const char *key_name,
char *str, size_t max_buf_sz, size_t *out_sz);
int EVP_PKEY_get_octet_string_param(EVP_PKEY *pkey, const char *key_name,
unsigned char *buf, size_t max_buf_sz,
size_t *out_sz);EVP_PKEY_gettable_params() returns a constant list of params indicating the names and types of key parameters that can be retrieved. See NOTES
These functions only work for EVP_PKEYs that contain a provider side key. EVP_PKEY_gettable_params() returns NULL on error or if it is not supported, All other methods return 1 if a value associated with the key's key_name was successfully returned, or 0 if there was an error. An error may be returned by methods EVP_PKEY_get_utf8_string_param() and EVP_PKEY_get_octet_string_param() if max_buf_sz is not big enough to hold the value. provider-keymgmt(7), HISTORY
These functions were added in OpenSSL 3.0. Copyright 2020 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 https://www.openssl.org/source/license.html.RETURN VALUES
EXAMPLES
#include <openssl/evp.h>
char *curve_name[64];
unsigned char pub[256];
BIGNUM *bn_priv = NULL;
/*
* NB: assumes 'key' is set up before the next step. In this example the key
* is an EC key.
*/
if (!EVP_PKEY_get_utf8_string_param(key, OSSL_PKEY_PARAM_EC_NAME,
curve_name, sizeof(curve_name), &len)) {
/* Error */
}
if (!EVP_PKEY_get_octet_string_param(key, OSSL_PKEY_PARAM_PUB_KEY,
pub, sizeof(pub), &len)) {
/* Error */
}
if (!EVP_PKEY_get_bn_param(key, OSSL_PKEY_PARAM_PRIV_KEY, &bn_priv)) {
/* Error */
}
BN_clear_free(bn_priv);SEE ALSO
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