NAME

       EVP_PKEY_new, EVP_PKEY_up_ref, EVP_PKEY_free, EVP_PKEY_new_raw_private_key,
       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

SYNOPSIS

        #include <openssl/evp.h>

        EVP_PKEY *EVP_PKEY_new(void);
        int EVP_PKEY_up_ref(EVP_PKEY *key);
        void EVP_PKEY_free(EVP_PKEY *key);

        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(int type, ENGINE *e,
                                              const unsigned char *key, size_t keylen);
        EVP_PKEY *EVP_PKEY_new_CMAC_key(ENGINE *e, const unsigned char *priv,
                                        size_t len, const EVP_CIPHER *cipher);
        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);

DESCRIPTION

       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_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() allocates a new EVP_PKEY. 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_HMAC, EVP_PKEY_POLY1305, EVP_PKEY_SIPHASH,
       EVP_PKEY_X25519, EVP_PKEY_ED25519, EVP_PKEY_X448 or EVP_PKEY_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_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_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.

       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.

NOTES

       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, EVP_PKEY_set1_DH or EVP_PKEY_set1_EC_KEY.

RETURN VALUES

       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_up_ref(), EVP_PKEY_get_raw_private_key() and EVP_PKEY_get_raw_public_key() return
       1 for success and 0 for failure.

SEE ALSO

       EVP_PKEY_set1_RSA(3), EVP_PKEY_set1_DSA, EVP_PKEY_set1_DH or EVP_PKEY_set1_EC_KEY

HISTORY

       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.

COPYRIGHT

       Copyright 2002-2020 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (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>.