OpenSSL::KDF.scrypt

static VALUE
kdf_scrypt(int argc, VALUE *argv, VALUE self)
{
    VALUE pass, salt, opts, kwargs[5], str;
    static ID kwargs_ids[5];
    size_t len;
    uint64_t N, r, p, maxmem;

    if (!kwargs_ids[0]) {
        kwargs_ids[0] = rb_intern_const("salt");
        kwargs_ids[1] = rb_intern_const("N");
        kwargs_ids[2] = rb_intern_const("r");
        kwargs_ids[3] = rb_intern_const("p");
        kwargs_ids[4] = rb_intern_const("length");
    }
    rb_scan_args(argc, argv, "1:", &pass, &opts);
    rb_get_kwargs(opts, kwargs_ids, 5, 0, kwargs);

    StringValue(pass);
    salt = StringValue(kwargs[0]);
    N = NUM2UINT64T(kwargs[1]);
    r = NUM2UINT64T(kwargs[2]);
    p = NUM2UINT64T(kwargs[3]);
    len = NUM2LONG(kwargs[4]);
    /*
     * OpenSSL uses 32MB by default (if zero is specified), which is too small.
     * Let's not limit memory consumption but just let malloc() fail inside
     * OpenSSL. The amount is controllable by other parameters.
     */
    maxmem = SIZE_MAX;

    str = rb_str_new(0, len);
    if (!EVP_PBE_scrypt(RSTRING_PTR(pass), RSTRING_LEN(pass),
                        (unsigned char *)RSTRING_PTR(salt), RSTRING_LEN(salt),
                        N, r, p, maxmem, (unsigned char *)RSTRING_PTR(str), len))
        ossl_raise(eKDF, "EVP_PBE_scrypt");

    return str;
}