 the returned key is <b>not</b> incremented and so the key must not be freed after use. These functions are deprecated. Applications should instead use the EVP_PKEY directly where possible. If access to the low level key parameters is required then applications should use <a href="../man3/EVP_PKEY_get_params.html">EVP_PKEY_get_params(3)</a> and other similar functions. To write an EVP_PKEY out use the OSSL_ENCODER APIs (see <a href="../man3/OSSL_ENCODER_CTX_new_for_pkey.html">OSSL_ENCODER_CTX_new_for_pkey(3