EVP_PKEY_CMP(3)

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

SYNOPSIS
libcrypto
#include <openssl/evp.h>
int
EVP_PKEY_missing_parameters(const EVP_PKEY *pkey);
int
EVP_PKEY_copy_parameters(EVP_PKEY *destination, const EVP_PKEY *source);
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
EVP_PKEY_missing_parameters() checks whether any public key parameters are missing from pkey.

EVP_PKEY_copy_parameters() copies all public key parameters from the source to the destination. If the algorithm does not use parameters, no action occurs.

EVP_PKEY_cmp_parameters() compares the public key parameters of a and b. This is only supported for algorithms that use parameters.

EVP_PKEY_cmp() compares the public key components of a and b. If the algorithm uses public key parameters, it also compares the parameters.

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

EVP_PKEY_copy_parameters() returns 1 for success or 0 for failure. In particular, it fails if the key types mismatch or if the public key parameters in the source are missing or incomplete.

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), EVP_PKEY_new(3), X509_get_pubkey_parameters(3)

HISTORY
EVP_PKEY_missing_parameters() and EVP_PKEY_copy_parameters() first appeared in SSLeay 0.8.0. EVP_PKEY_cmp_parameters() first appeared in SSLeay 0.9.0. These functions have been available since OpenBSD 2.4.

EVP_PKEY_cmp() first appeared in OpenSSL 0.9.8 and has been available since OpenBSD 4.5.