pub unsafe extern "C" fn PKCS5_PBKDF2_HMAC(
    password: *const c_char,
    password_len: usize,
    salt: *const u8,
    salt_len: usize,
    iterations: u32,
    digest: *const EVP_MD,
    key_len: usize,
    out_key: *mut u8
) -> c_int