GNU wannabee and Happy Hacking

StarPro64 (in Japanese)

NIIBE Yutaka — Wed, 20 Aug 2025 00:00:00 +0900

StarPro64 を普段使いの Desktop として使う(使えるか?)

今年の初夏に RISC-V のシングルボードコンピュータ StarPro64 が入手可能だったので購 …

Reliably Reproducible Only-One Keyboard Kit

NIIBE Yutaka — Wed, 19 Feb 2025 00:00:00 +0900

In 2025, I start a hardware/firmware project to build my own keyboard.

60% Keyboard Kit

I have been using 60% keyboard. For some years, it was my practice buying a kit (of GH60 variant) around end of year (with Aliexpress or Taobao) and building it in new year.

Basically …

On the edge of Curve25519 (safegcd256 for 32-bit machine)

NIIBE Yutaka — Fri, 08 Dec 2023 00:00:00 +0900

19 x 31 = 589 >= 587

I implemented safegcd256 for Gnuk. It uses signed 31-bit integers, and it does 19 iterations for p = 2**255 - 19.

Modular inversion

In the computation of X25519, we need to compute the modular inversion at the last step to get the value of x in …

Installing Debian Bookworm

NIIBE Yutaka — Fri, 19 May 2023 00:00:00 +0900

Second-hand PC, Dell Optilex

I installed Debian Bookworm to this machine. It took a half of day.

I use USB Bloutooth Dongle of 0a12:0001 for the machine.

Comments on Bookworm

Mostly, the installation procedure and the configuration for Bookworm was as same as my installation of Buster.

In the …

Experiments with Gomti

NIIBE Yutaka — Mon, 20 Mar 2023 00:00:00 +0900

Running the RNG to evaluate the output

In the Gomti collection, there are a few Verilog implementations for multiple targets. Currently, those implementations are under evaluation.

The RNG is "bare" version, with no conditioning component. That is, in the actual use case, it is assumed that adding conditioning component after …

Gomti, the collection of rational numbers (continued)

NIIBE Yutaka — Mon, 20 Mar 2023 00:00:00 +0900

Asynchronous RNG output

The first and the second entries are designed in a way that all components are clocked by CLK. These ones are straightforward. However, the parameter Kd can be even, which results sensitivity to jitter bad.

Another variant is possible, to allow Kd can be odd. It is …

Gomti, the collection of rational numbers (more)

NIIBE Yutaka — Tue, 07 Feb 2023 00:00:00 +0900

Use of XOR accumulator

I draw another schematics, the main part is like following.

Instead of a shift register and a set of xor gates, it only uses an accumulator and a single xor gate.

The shift register was used because I had an idea of changing the shift register …

Gomti, the collection of rational numbers

NIIBE Yutaka — Sat, 28 Jan 2023 00:00:00 +0900

I start a project, named Gomti. It's a collection of configurations and implementations to build a PLL-based true random number generater (TRNG). The central part of Gomti is actually, curated rational numbers to build PLL RNG.

The name

The name "gomti" is an acronym to remember the first part of …

SOS in OpenPGP

NIIBE Yutaka — Mon, 29 Mar 2021 00:00:00 +0900

I was not able to describe SOS itself accurately in ECC in OpenPGP by SOS.

So, this article is to augument the explanation.

SOS is a suggestion to OpenPGP implementations to address the zero removal/recovery problem. I know that implementations already handle it by adding zero recovary for Ed25519 …

ECC in OpenPGP by SOS

NIIBE Yutaka — Wed, 10 Mar 2021 00:00:00 +0900

In this article, I try to explain a specific way to improve current (as of March 2021) situation of OpenPGP with regards to EdDSA and ECDH with modern curves.

Specifically, I suggest a way to introduce SOS. But even if you won't introduce SOS methodology into your implementation of OpenPGP …

ECC in OpenPGP (as of March 2021)

NIIBE Yutaka — Tue, 09 Mar 2021 00:00:00 +0900

In this bug report, I describe how we can improve OpenPGP specification for ECC, so that different implementations can inter-operate well, and an implementation can avoid a bug. Here, my focus is ECC.

Firstly, I point out the single issue: Opaque Data Element should be available in OpenPGP. I name …

著作権について

NIIBE Yutaka — Tue, 09 Mar 2021 00:00:00 +0900

このサイトの文書について、わたくしの書いた部分は下記の許諾で利用できます。

CC-BY International 4.0: https://creativecommons.org/licenses/by/4.0/

コードの …

Flash Memory Read-Out Protection

NIIBE Yutaka — Mon, 01 Feb 2021 00:00:00 +0900

MCU usually supports a feature to disable reading out its content of flash memory for external use.

Such a feature is useful when we build a device like Gnuk Token, because we can make sure that secret data on a device cannot be read out.

Historically, this feature was implemented …

micro-SD card which contains the copy of git.gniibe.org

NIIBE Yutaka — Thu, 01 Oct 2020 00:00:00 +0900

micro-SD card

For those who need source code by physical media, Flying Stone Technology sells a microSD card (with SD card adapter) which contains all repositories at git.gniibe.org.

It includes the hardware designs of FST-01/G/SZ, FSM-55, thread library Chopstx, the firmware implementation of Gnuk, NeuG and …

Porting Chopstx to RISC-V MCU

NIIBE Yutaka — Wed, 15 Jan 2020 00:00:00 +0900

For GD32VF103 (Note: it's not GD32 F 103, but GD32 VF 103), I ported Chopstx in master. It will be released in Chopstx 2.0.

It was in 2018, when I ported Chopstx to GD32F103 in Chopstx 1.9. GD32F103 uses ARM Cortex-M3 core and peripherals are compatible to STM32F103 …

Distributing Flying Stone Tiny 01SZ as a kit

NIIBE Yutaka — Fri, 24 May 2019 00:00:00 +0900

I have started to distribute FST-01SZ as a kit.

What's in a bag?

On the FST-01SZ from factory, the firmware installed is: NeuG, the random number generator, version 1.0.9.

As shown in the photo above, the FST-01SZ Kit consists of an …

Tian Tian Xiang Shang - Another Hardware

NIIBE Yutaka — Thu, 25 Apr 2019 00:00:00 +0900

Now, initial TTXS is working well.

I'm porting TTXS to the board named Nucleo-32 L432, which is smaller. There used to be a single Nucleo board, which was STM32 Nucleo F103. It seemed that when the smaller one came, now, there are two different series, smaller Nucleo-32 and larger Nucleo-64 …

Tian Tian Xiang Shang - Hardware

NIIBE Yutaka — Mon, 04 Mar 2019 00:00:00 +0900

I start developing our own firmware implementation of smartcard reader.

Smartcard reader is a small computer which interfaces smartcard and host computer.

Although it is obvious to abuse it for MITM attack (since it is the device in the middle, by its definition), some people have tendency excluding such a …

Installing Debian Buster

NIIBE Yutaka — Tue, 19 Feb 2019 00:00:00 +0900

New Notebook PC from ShenZhen, China

Because keyboard of Acer C720 Chromebook became broken (perhaps due to my bringing it for travels), I bought Jumper EZbook 3 Pro this week in 2019. My choice was more physically-robust computer.

I installed Debian Buster (now "testing") to this machine. It took a …

Flying Stone Tiny 01SZ Test Plan

NIIBE Yutaka — Tue, 04 Dec 2018 00:00:00 +0900

We need to specify a test plan to manufacture a board. In order to encourage designing and manufacturing by yourselves, we show our test plan for Flying Stone Tiny 01SZ here.

This makes the reproducibility better, I suppose.

In my opinion, free hardware design should have a test plan to …