EVP_PKEY_cmp(3SSL)

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.

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

The funcion 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)