EVP_PKEY_cmp(3)			    OpenSSL		       EVP_PKEY_cmp(3)



NAME
       EVP_PKEY_copy_parameters, EVP_PKEY_missing_parameters,
       EVP_PKEY_cmp_parameters, EVP_PKEY_cmp - public key parameter and
       comparison functions

SYNOPSIS
	#include <openssl/evp.h>

	int EVP_PKEY_missing_parameters(const EVP_PKEY *pkey);
	int EVP_PKEY_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from);

	int EVP_PKEY_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b);
	int EVP_PKEY_cmp(const EVP_PKEY *a, const EVP_PKEY *b);

DESCRIPTION
       The function EVP_PKEY_missing_parameters() returns 1 if the public key
       parameters of pkey are missing and 0 if they are present or the
       algorithm doesn't use parameters.

       The function EVP_PKEY_copy_parameters() copies the parameters from key
       from to key to. An error is returned if the parameters are missing in
       from or present in both from and to and mismatch. If the parameters in
       from and to are both present and match this function has no effect.

       The function EVP_PKEY_cmp_parameters() compares the parameters of keys
       a and b.

       The function EVP_PKEY_cmp() compares the public key components and
       paramters (if present) of keys a and b.

NOTES
       The main purpose of the functions EVP_PKEY_missing_parameters() and
       EVP_PKEY_copy_parameters() is to handle public keys in certificates
       where the parameters are sometimes omitted from a public key if they
       are inherited from the CA that signed it.

       Since OpenSSL private keys contain public key components too the
       function EVP_PKEY_cmp() can also be used to determine if a private key
       matches a public key.

RETURN VALUES
       The function EVP_PKEY_missing_parameters() returns 1 if the public key
       parameters of pkey are missing and 0 if they are present or the
       algorithm doesn't use parameters.

       These functions EVP_PKEY_copy_parameters() returns 1 for success and 0
       for failure.

       The function EVP_PKEY_cmp_parameters() and EVP_PKEY_cmp() return 1 if
       the keys match, 0 if they don't match, -1 if the key types are
       different and -2 if the operation is not supported.

SEE ALSO
       EVP_PKEY_CTX_new(3), EVP_PKEY_keygen(3)



1.0.2k				  2017-01-26		       EVP_PKEY_cmp(3)