NAME

       EVP_PKEY_CTX_new, EVP_PKEY_CTX_new_id, EVP_PKEY_CTX_dup, EVP_PKEY_CTX_free - public key
       algorithm context functions.

SYNOPSIS

        #include <openssl/evp.h>

        EVP_PKEY_CTX *EVP_PKEY_CTX_new(EVP_PKEY *pkey, ENGINE *e);
        EVP_PKEY_CTX *EVP_PKEY_CTX_new_id(int id, ENGINE *e);
        EVP_PKEY_CTX *EVP_PKEY_CTX_dup(EVP_PKEY_CTX *ctx);
        void EVP_PKEY_CTX_free(EVP_PKEY_CTX *ctx);

DESCRIPTION

       The EVP_PKEY_CTX_new() function allocates public key algorithm context using the algorithm
       specified in pkey and ENGINE e.

       The EVP_PKEY_CTX_new_id() function allocates public key algorithm context using the
       algorithm specified by id and ENGINE e. It is normally used when no EVP_PKEY structure is
       associated with the operations, for example during parameter generation of key genration
       for some algorithms.

       EVP_PKEY_CTX_dup() duplicates the context ctx.

       EVP_PKEY_CTX_free() frees up the context ctx.

NOTES

       The EVP_PKEY_CTX structure is an opaque public key algorithm context used by the OpenSSL
       high level public key API. Contexts MUST NOT be shared between threads: that is it is not
       permissible to use the same context simultaneously in two threads.

RETURN VALUES

       EVP_PKEY_CTX_new(), EVP_PKEY_CTX_new_id(), EVP_PKEY_CTX_dup() returns either the newly
       allocated EVP_PKEY_CTX structure of NULL if an error occurred.

       EVP_PKEY_CTX_free() does not return a value.

SEE ALSO

       EVP_PKEY_new(3)

HISTORY

       These functions were first added to OpenSSL 1.0.0.