The key is optionally protected by passphrase. configargs can be used to fine-tune the export process by specifying and / or overriding options for the openssl configuration file.
openssl_pkey_export() exports key as a PEM encoded string and stores it into out (which is passed by reference). The key is optionally protected by passphrase. configargs can be used to fine-tune the export process by specifying and/or overriding options for the openssl configuration file. See openssl_csr_new() for more information about configargs. Returns TRUE on success or FALSE on failure.