Openloop Hardware Wallet

White Paper

Version 2.0 ｜ First published December 2025
Haudi Crypto, Inc. — Kazunori Asada, President & CEO

Executive Summary

Crypto assets and blockchain technology have matured into social infrastructure, and AI agents are beginning to participate in economic activity. Against this backdrop, this paper lays out the motivation behind — and the technical positioning of — Openloop, a dedicated hardware wallet and signer.

Four Questions

  1. Why is a hardware wallet / signer indispensable now?
  2. Why do we need a wallet built in Japan, by Japanese engineers?
  3. What value does Openloop deliver?
  4. In the age of AI agents, how do humans keep the power of “final approval”?

Conclusions

Chapter 1 — The Shift in How Society Views Crypto Assets

1.1 From “Shady Speculation” to “Social Infrastructure”

For a long time, crypto assets carried the image of “something speculative and shady,” driven by news of wild price swings, ICO scams, and exchange hacks.

But that reputation reflects events that happened around the technology — not the essence of the technology itself.

The essence of blockchain lies in the following:

Technical element Overview
Blockchain A distributed ledger that is extremely hard to tamper with
Smart contracts “Programmable money and contracts” that execute automatically when conditions are met
Web3 / DAOs A foundation for services and organizations that do not depend on a single administrator
DeFi Decentralized financial services
NFTs / RWAs Tokenization of digital and real-world assets

These technologies are already in real-world use across finance, gaming, payments, identity management, and more, and are increasingly regarded as foundational technology for the next-generation internet. Moreover, from 2025 onward a new phase is emerging in which AI agents autonomously conduct economic activity on the blockchain.

1.2 The “Custody Problem” Exposed by Exchange Failures

In November 2022, FTX — then the world’s second-largest crypto exchange — collapsed1. It came to light that roughly USD 10 billion of the USD 16 billion entrusted by customers had been diverted to affiliated companies, and about one million customers lost access to their assets.

The incident once again threw the fundamental nature of crypto assets into sharp relief:

“Whoever holds the private key owns the asset.”

Depositing assets with an exchange is fundamentally different from a bank deposit. Crypto exchanges have no deposit-insurance scheme, and their structure forces users to bear operational risk directly.

Chapter 2 — The Rise of Stablecoins and the Separation of “Real Demand”

2.1 The Growth of Price-Stable Digital Currencies

The single biggest reason crypto assets looked “shady” was the violence of their price swings. What is now resolving that problem is stablecoins — coins whose value is pegged to fiat currencies.

Market size of major stablecoins (as of December 2025)

Currency Issuer Market cap Market share
USDT Tether ~USD 185 billion ~60%
USDC Circle ~USD 78 billion ~25%
Others Various ~USD 45 billion ~15%

Sources:

USDC’s growth track record

According to Circle, USDC recorded the following growth from 2024 into 20255:

2.2 Separating Speculation from Real Demand

As stablecoins spread, a clear separation is taking hold:

Category Characteristics Representative examples
Speculative assets Held to bet on price moves BTC, ETH, altcoins
Practical currencies Value-stable, used for payments USDT, USDC, JPYC

2.3 Concrete Changes Brought by Stablecoins

Everyday payments and remittances

Business-to-business (B2B) settlement

Smart money (programmable money)

Tokenization of RWAs (Real World Assets)

Automatic settlement by AI agents

Stablecoins, combined with standardized settlement procedures, are an ideal infrastructure for AI agents. A world in which AI compares, selects, orders, and pays for goods on behalf of humans — end to end — is becoming reality.

Yet the more that settlement procedures become standardized and easy for AI to handle, the more a new question arises: “Is it acceptable for the AI to settle on its own? Who gives the final approval?”

3.1 Japan’s Early Lead in Legislation

In Japan, the amended Payment Services Act took effect in June 2023, establishing a legal framework for stablecoins ahead of the rest of the world6.

Under this law, stablecoins are distinguished from “crypto assets” and are defined as “electronic payment instruments” backed by fiat currency.

Issuance requirements

3.2 JPYC: Japan’s First Regulation-Compliant Yen Stablecoin

On October 27, 2025, JPYC Inc. officially launched “JPYC,” Japan’s first yen-denominated stablecoin compliant with the Payment Services Act7.

Characteristics of JPYC

Item Details
Issuance form Type II funds-transfer business (registered August 2025)
Supported chains Ethereum, Polygon, Avalanche
Backing assets Yen-denominated assets and Japanese government bonds (JGB)
Exchange rate 1 JPYC = 1 yen (exactly 1:1)
Transfer cap JPY 1 million per transfer (Type II limit)

Goal

JPYC states that it aims for an outstanding issuance of JPY 10 trillion over the next three years.

3.3 A Joint Stablecoin Initiative by the Megabanks

In 2025, Japan’s three megabanks — MUFG Bank, Sumitomo Mitsui Banking Corporation, and Mizuho Bank — announced a plan to jointly issue a stablecoin8.

Plan overview

3.4 DCJPY: A Tokenized-Deposit Initiative

DCJPY (Digital Currency Japanese Yen) is a digital currency that tokenizes bank deposits on the blockchain9. Full-scale operation began in August 2024.

DCJPY vs. JPYC

Item DCJPY JPYC
Category Tokenized deposit Stablecoin
Backing 1:1 with bank deposits Yen-denominated assets and government bonds
Issuer Banks Funds-transfer providers
Regulation Banking Act Payment Services Act

In September 2025, Japan Post Bank announced its entry into DCJPY, with a decision to launch services from FY2026 that draw on its JPY 190-trillion deposit base.

Chapter 4 — The Custody Problem and the Need for Hardware Wallets

4.1 “Where You Keep It” Is the Biggest Risk

The greatest risk with crypto assets is not price volatility but how the private key is managed.

The risks of exchanges

Risk factor Past cases
System vulnerabilities Mt. Gox (2014), Coincheck (2018)
Weak internal controls FTX (2022), 3Commas (2022)
Insolvency / misappropriation of funds FTX (2022), Voyager (2022)

Important: Exchanges may look like banks, but they have no deposit-insurance scheme, and users bear operational risk directly.

The risks of software wallets

Once a private key is stolen, the assets can never be recovered.

4.2 The State of Security Losses in 2025

According to the security-audit firm Hacken, USD 3.1 billion in crypto assets was stolen in the first half of 2025 alone10 — the worst pace on record, already exceeding the full-year 2024 loss of USD 2.2 billion.

Attacks on individual wallet holders accounted for roughly 23% of the total.

4.3 The Hardware Wallet: A “Vault” for the Digital Age

A hardware wallet is a dedicated security device with the following characteristics:

Characteristic Explanation
Complete isolation of the private key Generates and stores the private key inside the device and never lets it leave
Offline signing Performs all signing operations inside the device
Minimized attack surface Blocks attacks via PC, smartphone, and network
Physical authentication Requires a physical button press to approve a transaction

Main use cases

Chapter 5 — The State of the Hardware Wallet Market

5.1 Market Size and Growth Forecasts

The hardware wallet market is expanding rapidly.

Market size over time

Year Market size Source
2024 ~USD 470–510 million Straits Research, IMARC Group
2025 (forecast) ~USD 580 million Straits Research
2030 (forecast) ~USD 2.0 billion Mordor Intelligence
2033 (forecast) ~USD 2.4 billion IMARC Group

Sources:

Growth rate (CAGR)

CAGR forecasts for 2025–2033 by research firm:

A new factor accelerating this growth is the spread of AI agents. The more AI participates in economic transactions, the greater the demand for a hardware device by which humans grant final approval.

Units shipped

As of 2024, more than 5.8 million hardware wallets had been shipped worldwide.

5.2 Analysis by Segment

Share by connection method (2024)

By end user

By region

5.3 Major Players

The market is currently dominated by companies that are all based overseas.

Company Headquarters Flagship products Notes
Ledger France Nano S/X/Gen5 The world’s largest; protects ~USD 100 billion in assets14
Trezor Czech Republic Model T/Safe Open-source pioneer
Keystone China Keystone 3 Pro Air-gap specialist
SafePal Singapore S1 Focused on cost performance

Ledger’s 2025 developments

Chapter 6 — Why a “Made-in-Japan” Wallet Is Needed

6.1 The Shortcomings of Foreign-Made Wallets

For Japanese users, foreign-made hardware wallets present the following issues:

Issue Details
Language support Incomplete Japanese UI; manuals sometimes in English only
Technical support Concerns about the quality and speed of Japanese-language support
Legal alignment No consideration of consistency with Japan’s Payment Services Act or tax system
Transparency Difficulty in verifying the code or hardware design
Adoption by enterprises and government A high bar for adoption in domestic projects

6.2 A Bottleneck for the Growth of Web3 in Japan

The fact that a hardware wallet / signer industry has not grown in Japan is a fundamental bottleneck for the country’s future Web3 development.

Chapter 7 — Openloop: A Hardware Wallet and Signer Made in Japan

7.1 About the Developer

Kazunori Asada (developer)

7.2 Openloop’s Design Philosophy

Openloop is designed not as “an alternative to foreign products” but as a wallet and signer that will bear the foundation of Japan’s Web3 infrastructure.

Core principles

Principle Implementation
SE050 secure element Signing is completed inside an EAL6+ certified chip (ECDSA/EdDSA/RSA-2048); the private key is designed never to leave RAM
Air-gap support QR-code-based offline signing
Hybrid connectivity USB / Bluetooth / WalletConnect
Multi-currency Bitcoin, Ethereum, XRP, Solana, TRON, ERC-20, and stablecoins
FIDO2 security key CTAP2 passkeys (ES256/EdDSA) for passwordless authentication to web services
PIV/PKCS#11 signer SSH authentication, PDF signing, GPG signing, TLS client authentication (P-256/Ed25519/RSA-2048)
Japanese-first Fully Japanese UI and Japanese documentation
Transparency Detailed technical specifications and documented security design
An approval device for the AI age Realizes human final approval of AI-agent execution through a cryptographic signature

Openloop conforms to industry-standard specifications (BIP-32/39/44/174, EIP-155/191/712/1559, Ed25519, SLIP-0010, and others), ensuring compatibility with existing major wallet apps. For technical details, see the “Openloop Product Specification.”

7.3 Supported Currencies and Networks

Category Currencies/tokens Networks Notes
Bitcoin 1 (BTC) 2 Mainnet + Testnet
Solana 1 (SOL) 3 Mainnet + Devnet + Testnet
TRON 1 (TRX) 3 Mainnet + Shasta + Nile
XRP Ledger 1 (XRP) 2 Mainnet + Testnet
EVM 2,599 (ERC-20) 215 129 Mainnet + 86 Testnet
Total 2,603 225

Openloop supports signing for every EVM network and every ERC-20 token. Built-in currencies, tokens, and networks are shown by name on the device screen; those not built in can still be identified by Chain ID or contract address and signed.

7.4 dApp and WalletConnect Support

dApps (decentralized applications) are the next-generation applications that run on the blockchain. A wide range of services is emerging — DeFi (decentralized finance), NFT marketplaces, DAO governance, cross-chain bridges, and more.

Openloop supports WalletConnect v2 and can connect to hundreds of dApps through the desktop/mobile app Openloop Connect. Four chain families are supported — Ethereum/EVM, Bitcoin, Solana, and TRON — with transaction signing, message signing, batch signing, and sign-and-broadcast.

Using Openloop as a hardware signer lets you use these dApps safely:

Conventional software wallet Openloop + dApp
Private key stored on the PC/smartphone Private key protected inside the SE050 chip
Theft risk from malware Theft prevented by offline signing
Harm from phishing sites Signing content confirmed on the device screen

7.5 Compatible Wallets and Services

Openloop implements a Ledger-compatible protocol and integrates seamlessly with existing wallet apps and services.

7.6 Proof of Operation

From the development stage, Openloop has been validated on real blockchain networks. Across all currencies — Bitcoin, Ethereum, XRP, Solana, and TRON — it has successfully signed, transferred, and broadcast via every communication method: USB, BLE, QR (air-gap), and WalletConnect.

It has also successfully carried out a real transfer of the Japanese-yen stablecoin JPYC, demonstrating compatibility with a stablecoin compliant with Japanese law.

For details of the verified transactions, see the “Openloop Product Specification.”

Chapter 8 — The Future Openloop Opens Up

8.1 Use Cases for Individuals

Scene Openloop’s role
Overseas remittance Instant transfer to family (seconds to minutes)
Freelance income Same-day receipt of cross-border payments
Everyday payments Connecting as the backend of a smartphone app
Investment One-tap investment in tokenized securities
DAO participation Voting in local communities and neighborhood associations

8.2 Use Cases for Enterprises and Organizations

Enterprise use is projected to be several to several dozen times the market size of individual use.

Scene Openloop’s role
Transfers between overseas subsidiaries Zero fees, made instant
Supply-chain settlement Automated by smart contracts
Accounting Automated, tamper-proof invoice processing
Department-level fund management Separation of authority via multisig
Treasury Safe custody at the scale of billions of yen
Government services Turning subsidies and benefits into smart money

8.3 As a Foundation for Japan’s Digital Economy

Openloop is not merely a product; it functions as part of the following ecosystem:

Japan’s Web3 infrastructure

Layer Components
Stablecoin layer JPYC, DCJPY, megabank coins
Application layer DeFi, gaming, RWAs, government services
Wallet layer [Openloop]
Blockchain layer Ethereum, L2s, domestic chains

8.4 An Approval Device for the Age of AI Agents

The problem of “permission” between AI and humans

An era is arriving in which AI agents handle humans’ everyday work on their behalf. Scheduling, information gathering, document drafting — the domains AI can process autonomously are expanding rapidly.

However, the mechanism by which we grant an AI permission to “go ahead and execute” has a fundamental vulnerability.

In today’s AI agents, whether an action is permitted is decided by “a response to a prompt.” If a human answers “OK” on the screen, it runs; if they answer “No,” it stops. But this is nothing more than an arrangement based on trust between human and AI — there is no cryptographic guarantee that the arrangement is honored.

The risks of assets held in software

PCs and smartphones store credit-card details, bank accounts, and the private keys to crypto assets. These are constantly exposed to the following risks:

Risk Explanation
External hacking Malware, phishing, zero-day attacks
AI malfunction Misinterpretation of instructions, hallucination
Abuse of AI Prompt injection, supply-chain attacks

In February 2026, the combination of “Moltbook” — an SNS built exclusively for AI agents — and the skill-execution platform “OpenClaw” made this problem concrete. On a platform where 1.5 million AI agents participated, a database vulnerability leaked the API keys of every agent, leading to unauthorized access to crypto wallets via those agents and to private keys being stolen by fake trading tools laced with malware15. It is an early real-world example of what happens when AI is given broad access rights in software.

An approval system composed of software alone cannot fundamentally eliminate these risks.

Cryptographic approval — the hardware signer

The only way for a human to prove cryptographically to an AI that “you may execute this” is a signature made by a physically independent hardware device.

What an AI can do autonomously (gather information, analyze, propose) and what requires explicit human approval (payments, contracts, asset transfers) should be clearly separated. The latter calls not for an “OK” button in software but for a cryptographic signature on an independent device.

This is exactly the same principle by which digital certificates and hardware tokens are used for a company’s banking transactions.

The “global standard approval procedure” that blockchain makes possible

With the spread of stablecoins and smart contracts, the procedures for payments, contracts, and asset transfers are being standardized on a global scale. Cross-border remittances and complex conditional contracts alike are all executed with a single signature on the blockchain.

While this standardization dramatically increases convenience, it makes the question “who gives the final approval, and how?” all the more pressing. The more the procedures are unified, the more the approval mechanism matters.

The essence of Openloop

Openloop is a crypto-asset wallet and, at the same time, a device that plays a larger role.

Conventional positioning The positioning going forward
A vault for crypto assets An approval device that connects humans and AI
A Web3 signing device The standard signer for the age of AI agents
A transfer tool for specific currencies A global-standard interface for approving payments and contracts

However smart AI becomes, the final decision to move assets stays in human hands. A device that proves that intent cryptographically — that is the essence of Openloop.

Chapter 9 — Closing

An Irreversible Trend

Crypto assets, Web3, stablecoins, RWAs — these have already become an irreversible trend as the new foundation of the world economy.

In 2025 the market cap of stablecoins surpassed USD 230 billion; the three megabanks are moving to issue a yen stablecoin; and Japan Post Bank is entering tokenized deposits at the scale of JPY 190 trillion. The age has begun in which AI agents take part in economic activity, making decisions and executing them on behalf of humans.

This is no longer a story about “the crypto industry.” It is a fundamental transformation of financial infrastructure and of the relationship between humans and AI.

Japan’s Choice

A world in which every gateway wallet is foreign-made is, for Japan, both a major risk and a lost opportunity.

Openloop is built to help support one corner of Japan’s Web3 infrastructure and to safeguard the human right of final approval in the age of AI agents — the first step for a domestically made signer.

From Japan, we will build a society in which anyone can safely enter and leave the Web3 world.

This white paper explains the background, market, and design philosophy of the product. For technical details, please refer to the following documents.

Document list

Document Overview Availability
Openloop White Paper This document. Development background, market, design philosophy, and vision Public
Openloop Product Specification Technical specifications, supported standards, hardware configuration, proof of operation Public
Openloop User Manual How to operate, feature descriptions, troubleshooting Public
Openloop Security Architecture Encryption design, key management, SE050 integration specification NDA signatories only
Reader Recommended documents
Investors and business partners White Paper
General users User Manual
Developers and engineers Product Specification + User Manual
Security auditors Product Specification + Security Architecture (NDA required)

References

Market data and statistics

  1. CoinMarketCap - Tether (USDT)
    https://coinmarketcap.com/currencies/tether/
  2. CoinMarketCap - USD Coin (USDC)
    https://coinmarketcap.com/currencies/usd-coin/
  3. Circle, “State of the USDC Economy 2025”
    https://www.circle.com/reports/state-of-the-usdc-economy
  4. CoinLaw, “Tether Statistics 2025”
    https://coinlaw.io/tether-statistics/
  5. CoinLaw, “USD Coin Statistics 2025”
    https://coinlaw.io/usd-coin-statistics/

Market research reports

  1. Straits Research, “Hardware Wallet Market Report 2033”
    https://straitsresearch.com/report/hardware-wallet-market
  2. IMARC Group, “Hardware Wallet Market 2025-2033”
    https://www.imarcgroup.com/hardware-wallet-market
  3. Mordor Intelligence, “Hardware Wallet Market”
    https://www.mordorintelligence.com/industry-reports/hardware-wallet-market

Japan’s regulations and stablecoins

  1. Nomura Research Institute, “Japan’s first yen-denominated stablecoin to be issued” (September 2025)
    https://www.nri.com/jp/media/column/kiuchi/20250905_2.html
  2. Nomura Research Institute, “The three megabanks to issue a stablecoin” (October 2025)
    https://www.nri.com/jp/media/column/kiuchi/20251020.html
  3. JPYC Inc. press release
    https://prtimes.jp/main/html/rd/p/000000283.000054018.html
  4. Nikkei, “Three megabanks to jointly issue a stablecoin”
    https://www.nikkei.com/article/DGXZQOUB144IX0U5A011C2000000/

Security and exchange failures

  1. Nomura Research Institute, “The bankruptcy of FTX” (November 2022)
    https://www.nri.com/jp/knowledge/blog/lst/2022/fis/kiuchi/1114
  2. Finance Magnates, “Ledger Weighs IPO” (November 2025)
    https://www.financemagnates.com/cryptocurrency/ledger-weighs-new-york-ipo-as-crypto-security-breaches-hit-22-billion/

AI-agent security

  1. Wiz, “Hacking Moltbook: AI Social Network Reveals 1.5M API Keys” (February 2026)
    https://www.wiz.io/blog/exposed-moltbook-database-reveals-millions-of-api-keys
  2. MIT Technology Review, “Moltbook was peak AI theater” (February 2026)
    https://www.technologyreview.com/2026/02/06/1132448/moltbook-was-peak-ai-theater/

Hardware wallet makers

  1. Ledger official site
    https://www.ledger.com/
  2. CoinLaw, “Ledger and Trezor Launch 2025 Wallets”
    https://coinlaw.io/ledger-trezor-2025-wallets/

Revision History

Version Date Changes
1.0 December 2025 Initial version
1.1 January 2026 Reflected the SE050 secure-element design; added proof of operation (successful JPYC transfer); updated the documentation set to four documents
1.2 January 2026 Added details of supported standards, networks, and tokens; expanded the dApp-support section; added compatible wallet software
1.3 January 2026 Added an explanation of the display of built-in / non-built-in tokens and networks; updated the JPYC v2 address
1.4 January 2026 Added WalletConnect BIP122 (Bitcoin) support; added BTC message signing
1.5 February 2026 Added TRON support; brought supported standards, signing methods, and proof of operation up to date
2.0 February 2026 Fully revised as a statement of purpose; added the positioning as an approval device for the age of AI agents; migrated technical details to the Product Specification

The contents of this document are based on information as of February 19, 2026. Market data and the regulatory situation are subject to change.

© 2026 Haudi Crypto, Inc. All rights reserved.

  1. Nomura Research Institute, “The bankruptcy of the crypto exchange FTX and the spreading turmoil” (November 2022) https://www.nri.com/jp/knowledge/blog/lst/2022/fis/kiuchi/1114↩︎

  2. https://coinmarketcap.com/currencies/tether/↩︎

  3. https://coinmarketcap.com/currencies/usd-coin/↩︎

  4. https://straitsresearch.com/report/hardware-wallet-market↩︎

  5. Circle, “State of the USDC Economy 2025” https://www.circle.com/reports/state-of-the-usdc-economy↩︎

  6. Nomura Research Institute, “Japan’s first yen-denominated stablecoin to be issued” (September 2025) https://www.nri.com/jp/media/column/kiuchi/20250905_2.html↩︎

  7. JPYC Inc. press release, “Japan’s first Japanese-yen stablecoin ‘JPYC’ officially launched” (October 2025) https://prtimes.jp/main/html/rd/p/000000283.000054018.html↩︎

  8. Nikkei, “Three megabanks to jointly issue a stablecoin” (October 2025) https://www.nikkei.com/article/DGXZQOUB144IX0U5A011C2000000/↩︎

  9. CoinChoice, “Complete guide to the digital currency DCJPY, 2025 edition” https://coinchoice.net/dcjpy-complete-2025/↩︎

  10. Finance Magnates, “Ledger Weighs New York IPO as Crypto Security Breaches Hit $2.2 Billion” (November 2025) https://www.financemagnates.com/cryptocurrency/ledger-weighs-new-york-ipo-as-crypto-security-breaches-hit-22-billion/↩︎

  11. https://straitsresearch.com/report/hardware-wallet-market↩︎

  12. https://www.imarcgroup.com/hardware-wallet-market↩︎

  13. https://www.mordorintelligence.com/industry-reports/hardware-wallet-market↩︎

  14. Finance Magnates (see above)↩︎

  15. Wiz, “Hacking Moltbook: AI Social Network Reveals 1.5M API Keys” (February 2026) https://www.wiz.io/blog/exposed-moltbook-database-reveals-millions-of-api-keys↩︎