EVP_PKEY_CMP(3)            Library Functions Manual            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
     #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_asn1_set_public(3), 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.

Linux 6.8.2-arch2-1              March 5, 2024             Linux 6.8.2-arch2-1