EVP_PKEY_CTX_NEW(3ossl) OpenSSL EVP_PKEY_CTX_NEW(3ossl)
NAME
EVP_PKEY_CTX_new, EVP_PKEY_CTX_new_id, EVP_PKEY_CTX_new_from_name,
EVP_PKEY_CTX_new_from_pkey, EVP_PKEY_CTX_dup, EVP_PKEY_CTX_free,
EVP_PKEY_CTX_is_a - public key algorithm context functions
SYNOPSIS
#include <openssl/evp.h>
EVP_PKEY_CTX *EVP_PKEY_CTX_new(EVP_PKEY *pkey, ENGINE *e);
EVP_PKEY_CTX *EVP_PKEY_CTX_new_id(int id, ENGINE *e);
EVP_PKEY_CTX *EVP_PKEY_CTX_new_from_name(OSSL_LIB_CTX *libctx,
const char *name,
const char *propquery);
EVP_PKEY_CTX *EVP_PKEY_CTX_new_from_pkey(OSSL_LIB_CTX *libctx,
EVP_PKEY *pkey,
const char *propquery);
EVP_PKEY_CTX *EVP_PKEY_CTX_dup(const EVP_PKEY_CTX *ctx);
void EVP_PKEY_CTX_free(EVP_PKEY_CTX *ctx);
int EVP_PKEY_CTX_is_a(EVP_PKEY_CTX *ctx, const char *keytype);
DESCRIPTION
The EVP_PKEY_CTX_new(3) function allocates public key algorithm context
using the pkey key type and ENGINE e.
The EVP_PKEY_CTX_new_id() function allocates public key algorithm
context using the key type specified by id and ENGINE e.
The EVP_PKEY_CTX_new_from_name() function allocates a public key
algorithm context using the library context libctx (see
OSSL_LIB_CTX(3)), the key type specified by name and the property query
propquery. None of the arguments are duplicated, so they must remain
unchanged for the lifetime of the returned EVP_PKEY_CTX or of any of
its duplicates. Read further about the possible names in "NOTES"
below.
The EVP_PKEY_CTX_new_from_pkey() function allocates a public key
algorithm context using the library context libctx (see
OSSL_LIB_CTX(3)) and the algorithm specified by pkey and the property
query propquery. None of the arguments are duplicated, so they must
remain unchanged for the lifetime of the returned EVP_PKEY_CTX or any
of its duplicates.
EVP_PKEY_CTX_new_id() and EVP_PKEY_CTX_new_from_name() are normally
used when no EVP_PKEY structure is associated with the operations, for
example during parameter generation or key generation for some
algorithms.
EVP_PKEY_CTX_dup() duplicates the context ctx. It is not supported for
a keygen operation.
EVP_PKEY_CTX_free() frees up the context ctx. If ctx is NULL, nothing
is done.
EVP_PKEY_is_a() checks if the key type associated with ctx is keytype.
NOTES
On EVP_PKEY_CTX
The EVP_PKEY_CTX structure is an opaque public key algorithm context
used by the OpenSSL high-level public key API. Contexts MUST NOT be
shared between threads: that is it is not permissible to use the same
context simultaneously in two threads.
On Key Types
We mention "key type" in this manual, which is the same as "algorithm"
in most cases, allowing either term to be used interchangeably. There
are algorithms where the key type and the algorithm of the operations
that use the keys are not the same, such as EC keys being used for
ECDSA and ECDH operations.
Key types are given in two different manners:
Legacy NID or EVP_PKEY type
This is the id used with EVP_PKEY_CTX_new_id().
These are EVP_PKEY_RSA, EVP_PKEY_RSA_PSS, EVP_PKEY_DSA,
EVP_PKEY_DH, EVP_PKEY_EC, EVP_PKEY_SM2, EVP_PKEY_X25519,
EVP_PKEY_X448, and are used by legacy methods.
Name strings
This is the name used with EVP_PKEY_CTX_new_from_name().
These are names like "RSA", "DSA", and what's available depends on
what providers are currently accessible.
The OpenSSL providers offer a set of key types available this way,
please see OSSL_PROVIDER-FIPS(7) and OSSL_PROVIDER-default(7) and
related documentation for more information.
RETURN VALUES
EVP_PKEY_CTX_new(3), EVP_PKEY_CTX_new_id() and EVP_PKEY_CTX_dup() return
either the newly allocated EVP_PKEY_CTX structure or NULL if an error
occurred.
EVP_PKEY_CTX_free() does not return a value.
EVP_PKEY_CTX_is_a() returns 1 for true and 0 for false.
SEE ALSO
EVP_PKEY_new(3)
HISTORY
The EVP_PKEY_CTX_new(3), EVP_PKEY_CTX_new_id(), EVP_PKEY_CTX_dup() and
EVP_PKEY_CTX_free() functions were added in OpenSSL 1.0.0.
The EVP_PKEY_CTX_new_from_name() and EVP_PKEY_CTX_new_from_pkey()
functions were added in OpenSSL 3.0.
COPYRIGHT
Copyright 2006-2021 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>.
3.3.2 2024-09-04 EVP_PKEY_CTX_NEW(3ossl)
openssl 3.3.2 - Generated Thu Sep 12 14:12:21 CDT 2024