EVP_PKEY, EVP_PKEY_new, EVP_PKEY_up_ref, EVP_PKEY_dup, EVP_PKEY_free,
EVP_PKEY_new_raw_private_key_ex, EVP_PKEY_new_raw_private_key,
EVP_PKEY_new_raw_public_key_ex, EVP_PKEY_new_raw_public_key,
EVP_PKEY_new_CMAC_key, EVP_PKEY_new_mac_key, EVP_PKEY_get_raw_private_key,
EVP_PKEY_get_raw_public_key - public/private key allocation and raw key
handling functions
#include <openssl/evp.h>
typedef evp_pkey_st EVP_PKEY;
EVP_PKEY *EVP_PKEY_new(void);
int EVP_PKEY_up_ref(EVP_PKEY *key);
EVP_PKEY *EVP_PKEY_dup(EVP_PKEY *key);
void EVP_PKEY_free(EVP_PKEY *key);
EVP_PKEY *EVP_PKEY_new_raw_private_key_ex(OSSL_LIB_CTX *libctx,
const char *keytype,
const char *propq,
const unsigned char *key,
size_t keylen);
EVP_PKEY *EVP_PKEY_new_raw_private_key(int type, ENGINE *e,
const unsigned char *key, size_t keylen);
EVP_PKEY *EVP_PKEY_new_raw_public_key_ex(OSSL_LIB_CTX *libctx,
const char *keytype,
const char *propq,
const unsigned char *key,
size_t keylen);
EVP_PKEY *EVP_PKEY_new_raw_public_key(int type, ENGINE *e,
const unsigned char *key, size_t keylen);
EVP_PKEY *EVP_PKEY_new_mac_key(int type, ENGINE *e, const unsigned char *key,
int keylen);
int EVP_PKEY_get_raw_private_key(const EVP_PKEY *pkey, unsigned char *priv,
size_t *len);
int EVP_PKEY_get_raw_public_key(const EVP_PKEY *pkey, unsigned char *pub,
size_t *len);
The following function has been deprecated since OpenSSL 3.0, and can be hidden
entirely by defining
OPENSSL_API_COMPAT with a suitable version value,
see
openssl_user_macros(7):
EVP_PKEY *EVP_PKEY_new_CMAC_key(ENGINE *e, const unsigned char *priv,
size_t len, const EVP_CIPHER *cipher);
EVP_PKEY is a generic structure to hold diverse types of asymmetric keys
(also known as "key pairs"), and can be used for diverse operations,
like signing, verifying signatures, key derivation, etc. The asymmetric keys
themselves are often referred to as the "internal key", and are
handled by backends, such as providers (through
EVP_KEYMGMT(3)) or
ENGINEs.
Conceptually, an
EVP_PKEY internal key may hold a private key, a public
key, or both (a keypair), and along with those, key parameters if the key type
requires them. The presence of these components determine what operations can
be made; for example, signing normally requires the presence of a private key,
and verifying normally requires the presence of a public key.
EVP_PKEY has also been used for MAC algorithm that were conceived as
producing signatures, although not being public key algorithms;
"POLY1305", "SIPHASH", "HMAC", "CMAC".
This usage is considered legacy and is discouraged in favor of the
EVP_MAC(3) API.
The
EVP_PKEY_new() function allocates an empty
EVP_PKEY structure
which is used by OpenSSL to store public and private keys. The reference count
is set to
1.
EVP_PKEY_up_ref() increments the reference count of
key.
EVP_PKEY_dup() duplicates the
key. The
key must not be
ENGINE based or a raw key, otherwise the duplication will fail.
EVP_PKEY_free() decrements the reference count of
key and, if the
reference count is zero, frees it up. If
key is NULL, nothing is done.
EVP_PKEY_new_raw_private_key_ex() allocates a new
EVP_PKEY. Unless
an engine should be used for the key type, a provider for the key is found
using the library context
libctx and the property query string
propq. The
keytype argument indicates what kind of key this is.
The value should be a string for a public key algorithm that supports raw
private keys, i.e one of "X25519", "ED25519",
"X448" or "ED448".
key points to the raw private
key data for this
EVP_PKEY which should be of length
keylen. The
length should be appropriate for the type of the key. The public key data will
be automatically derived from the given private key data (if appropriate for
the algorithm type).
EVP_PKEY_new_raw_private_key() does the same as
EVP_PKEY_new_raw_private_key_ex() except that the default library
context and default property query are used instead. If
e is non-NULL
then the new
EVP_PKEY structure is associated with the engine
e.
The
type argument indicates what kind of key this is. The value should
be a NID for a public key algorithm that supports raw private keys, i.e. one
of
EVP_PKEY_X25519,
EVP_PKEY_ED25519,
EVP_PKEY_X448 or
EVP_PKEY_ED448.
EVP_PKEY_new_raw_private_key_ex() and
EVP_PKEY_new_raw_private_key() may also be used with most MACs
implemented as public key algorithms, so key types such as "HMAC",
"POLY1305", "SIPHASH", or their NID form
EVP_PKEY_POLY1305,
EVP_PKEY_SIPHASH,
EVP_PKEY_HMAC are
also accepted. This usage is, as mentioned above, discouraged in favor of the
EVP_MAC(3) API.
EVP_PKEY_new_raw_public_key_ex() works in the same way as
EVP_PKEY_new_raw_private_key_ex() except that
key points to the
raw public key data. The
EVP_PKEY structure will be initialised without
any private key information. Algorithm types that support raw public keys are
"X25519", "ED25519", "X448" or
"ED448".
EVP_PKEY_new_raw_public_key() works in the same way as
EVP_PKEY_new_raw_private_key() except that
key points to the raw
public key data. The
EVP_PKEY structure will be initialised without any
private key information. Algorithm types that support raw public keys are
EVP_PKEY_X25519,
EVP_PKEY_ED25519,
EVP_PKEY_X448 or
EVP_PKEY_ED448.
EVP_PKEY_new_mac_key() works in the same way as
EVP_PKEY_new_raw_private_key(). New applications should use
EVP_PKEY_new_raw_private_key() instead.
EVP_PKEY_get_raw_private_key() fills the buffer provided by
priv
with raw private key data. The size of the
priv buffer should be in
*len on entry to the function, and on exit
*len is updated with
the number of bytes actually written. If the buffer
priv is NULL then
*len is populated with the number of bytes required to hold the key.
The calling application is responsible for ensuring that the buffer is large
enough to receive the private key data. This function only works for
algorithms that support raw private keys. Currently this is:
EVP_PKEY_HMAC,
EVP_PKEY_POLY1305,
EVP_PKEY_SIPHASH,
EVP_PKEY_X25519,
EVP_PKEY_ED25519,
EVP_PKEY_X448 or
EVP_PKEY_ED448.
EVP_PKEY_get_raw_public_key() fills the buffer provided by
pub
with raw public key data. The size of the
pub buffer should be in
*len on entry to the function, and on exit
*len is updated with
the number of bytes actually written. If the buffer
pub is NULL then
*len is populated with the number of bytes required to hold the key.
The calling application is responsible for ensuring that the buffer is large
enough to receive the public key data. This function only works for algorithms
that support raw public keys. Currently this is:
EVP_PKEY_X25519,
EVP_PKEY_ED25519,
EVP_PKEY_X448 or
EVP_PKEY_ED448.
EVP_PKEY_new_CMAC_key() works in the same way as
EVP_PKEY_new_raw_private_key() except it is only for the
EVP_PKEY_CMAC algorithm type. In addition to the raw private key data,
it also takes a cipher algorithm to be used during creation of a CMAC in the
cipher argument. The cipher should be a standard encryption-only
cipher. For example AEAD and XTS ciphers should not be used.
Applications should use the
EVP_MAC(3) API instead and set the
OSSL_MAC_PARAM_CIPHER parameter on the
EVP_MAC_CTX object with
the name of the cipher being used.
The
EVP_PKEY structure is used by various OpenSSL functions which require
a general private key without reference to any particular algorithm.
The structure returned by
EVP_PKEY_new() is empty. To add a private or
public key to this empty structure use the appropriate functions described in
EVP_PKEY_set1_RSA(3),
EVP_PKEY_set1_DSA(3),
EVP_PKEY_set1_DH(3) or
EVP_PKEY_set1_EC_KEY(3).
EVP_PKEY_new(),
EVP_PKEY_new_raw_private_key(),
EVP_PKEY_new_raw_public_key(),
EVP_PKEY_new_CMAC_key() and
EVP_PKEY_new_mac_key() return either the newly allocated
EVP_PKEY structure or NULL if an error occurred.
EVP_PKEY_dup() returns the key duplicate or NULL if an error occurred.
EVP_PKEY_up_ref(),
EVP_PKEY_get_raw_private_key() and
EVP_PKEY_get_raw_public_key() return 1 for success and 0 for failure.
EVP_PKEY_set1_RSA(3),
EVP_PKEY_set1_DSA(3),
EVP_PKEY_set1_DH(3) or
EVP_PKEY_set1_EC_KEY(3)
The
EVP_PKEY_new() and
EVP_PKEY_free() functions exist in all
versions of OpenSSL.
The
EVP_PKEY_up_ref() function was added in OpenSSL 1.1.0.
The
EVP_PKEY_new_raw_private_key(),
EVP_PKEY_new_raw_public_key(),
EVP_PKEY_new_CMAC_key(),
EVP_PKEY_new_raw_private_key() and
EVP_PKEY_get_raw_public_key() functions were added in OpenSSL 1.1.1.
The
EVP_PKEY_dup(),
EVP_PKEY_new_raw_private_key_ex(), and
EVP_PKEY_new_raw_public_key_ex() functions were added in OpenSSL 3.0.
The
EVP_PKEY_new_CMAC_key() was deprecated in OpenSSL 3.0.
The documentation of
EVP_PKEY was amended in OpenSSL 3.0 to allow there
to be the private part of the keypair without the public part, where this was
previously implied to be disallowed.
Copyright 2002-2023 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
<
https://www.openssl.org/source/license.html>.