pub unsafe extern "C" fn gcm_auth_decrypt( ctx: *mut gcm_context, length: size_t, iv: *const c_uchar, iv_len: size_t, add: *const c_uchar, add_len: size_t, tag: *const c_uchar, tag_len: size_t, input: *const c_uchar, output: *mut c_uchar) -> c_int
