How to Safely Store Large Crypto Holdings in a Decentralized Wallet

Posted bymathmath

中文版请见下方 ↓

Your everyday wallet is built for convenience: you connect it to DApps, sign approvals, swap tokens, and keep it on a phone full of other apps. That is fine for spending money. It is not how you should keep savings you cannot afford to lose.

This guide shows a simple way to keep large holdings in MathWallet, a decentralized wallet where only you hold the keys. All you need is a spare iPhone, a pen and paper.

Two principles

Everything below follows from two rules:

  1. A dedicated, always-updated iPhone. The phone is used for nothing except this wallet, and it runs the latest version of iOS every time you use it. This protects you against attacks at the app and operating-system level.
  2. A receive-only wallet. The wallet that holds your assets has never sent a transaction. As soon as it sends one, you move everything left in it to a brand-new wallet that has never sent anything. This protects you against possible future weaknesses in the cryptography behind private keys, including attacks by quantum computers.

Step 1: Prepare a spare iPhone

  • Use an iPhone you no longer need for anything else. It must be new enough to run the latest iOS. Apple lists the supported models for each iOS release. A phone that is not on the list no longer gets security fixes and is not suitable.
  • From now on, this iPhone has one job: storing and managing your large holdings. Don't use it to browse, chat, check email or play games, and don't lend it to anyone.

Step 2: Erase it and set it up clean

  1. Go to Settings > General > Transfer or Reset iPhone > Erase All Content and Settings.
  2. When the phone restarts, set it up as a new iPhone. Do not restore from a backup, because a backup brings back the old apps and data.
  3. Set a strong passcode (six digits or a longer alphanumeric code) and turn on Face ID or Touch ID.
  4. You need an Apple ID to download from the App Store. Ideally, use a separate Apple ID just for this phone, with a strong password and two-factor authentication.
  5. Turn off iCloud Backup on this phone. Your paper copy of the recovery phrase (Step 4) is your backup.
  6. Go to Settings > General > Software Update, install the latest iOS, and turn on Automatic Updates.
  7. Don't install any other apps. You don't need a SIM card either; connect to a trusted Wi-Fi network only when you update or make a transaction.

Every app is software that can have bugs or be malicious, so every extra app is another way in. A phone with nothing on it but the system and the wallet leaves an attacker very little to work with.

Step 3: Install MathWallet from the official website

On the iPhone, open Safari, go to the official MathWallet website https://mathwallet.org/, and follow its link to the App Store to install MathWallet.

Don't search the App Store and install whatever comes up, and don't use download links from chats, ads or strangers. Copycat wallet apps exist, and they are built to steal recovery phrases.

Step 4: Create a brand-new wallet

  • Create a new wallet. Don't import an existing one. A recovery phrase or private key you have used before has passed through other phones and apps, and maybe your clipboard or cloud storage. You can't be sure it was never exposed.
  • Set a strong wallet password that you don't use anywhere else.
  • Write the recovery phrase on paper. No screenshots, photos, notes apps, cloud drives or messages to yourself. Keep the paper (ideally two copies) in safe, separate places. If this iPhone is lost or broken, the paper is the only way to get your assets back.
  • Optional but recommended: before you deposit anything large, check your paper copy. Remove the wallet, restore it from the paper on this same iPhone, and make sure the address is the same as before.

Step 5: Move your assets in

  • Always take the receiving address from MathWallet on this iPhone, not from the transaction history of your other wallet or exchange. Scammers send tiny transfers from look-alike addresses so that a fake one shows up in your history ("address poisoning"). Check the full address, not just the first and last few characters.
  • Send a small test amount first. Once it arrives, send the rest.
  • From now on, this wallet only receives. Don't connect it to DApps, don't sign approvals or messages, and ignore unknown tokens or NFTs that show up in it; they are often phishing bait.

Signing a message reveals your public key just as sending a transaction does, so under Principle 2 a signature counts as "sending".

Step 6: When you need to send assets out

  1. Update iOS first. Connect to Wi-Fi and install any pending iOS update before you open the wallet.
  2. Send the transaction you need.
  3. The wallet now has an outgoing record, so it is no longer receive-only. Create a new wallet (with a new recovery phrase) in MathWallet on the same iPhone, and back up its recovery phrase on paper as in Step 4.
  4. Move everything left in the old wallet to the new one, on every chain. On Ethereum and other EVM chains, fees are paid in the native coin, so move tokens first and the native coin last.
  5. The new wallet is now your vault. Never receive into the old wallet again, and update anywhere its address is saved, such as exchange withdrawal whitelists. Once the old wallet is empty, you can remove it from the app.

If you rarely touch your holdings, this only costs a few extra fees now and then, which is a small price for a vault that stays clean.

Why this works

Principle 1: a clean, updated phone keeps attackers out

Most thefts don't break cryptography; they go around it. A malicious app, a phishing link or an unpatched security hole in the system can be enough to reach a wallet's keys. Apple regularly fixes security holes in iOS, and some of them are already being used by attackers by the time they are fixed. An up-to-date phone with no other apps closes most of these doors.

When Apple stops releasing updates for your model, it is time to retire the phone: set up a newer iPhone the same way, create a new wallet on it, and move your assets over.

Principle 2: a wallet that has never sent anything keeps its public key hidden

Your private key controls your assets, and a public key is calculated from it. On many chains, your address is a hash (a kind of fingerprint) of that public key. With today's computers, working back from a public key to the private key is practically impossible. However:

  • Quantum computers. A large enough quantum computer running Shor's algorithm could, in theory, calculate a private key from its public key. No one knows when, or whether, such a machine will exist, but large holdings are often kept for many years.
  • Flaws in signing. Bugs in how signatures are created, such as weak randomness in a faulty implementation, have in the past let attackers recover private keys from signatures published on the blockchain.

Hash functions are not known to be vulnerable to quantum computers in the same way. On many chains, the public key only becomes visible when you sign something, whether a transaction or a message. Until then, all anyone can see is your address, and an address alone gives an attacker nothing to work with. That is why the vault never signs anything, and why it is emptied into a fresh wallet as soon as it does.

Good to know: This protection depends on how a chain creates addresses. It applies to chains where the address is a hash of the public key, such as Bitcoin SegWit (bc1q…) and legacy addresses, Ethereum and other EVM chains, and TRON. On chains where the address is the public key, such as Solana, Polkadot and Bitcoin Taproot (bc1p…) addresses, the public key is visible from the start. For BTC, if you can choose, a SegWit address (bc1q…) is the better choice for long-term storage.

Quick checklist

  • A spare iPhone that supports the latest iOS
  • Erased and set up as a new iPhone; no backup restored; no other apps
  • Latest iOS installed, Automatic Updates on
  • MathWallet installed through https://mathwallet.org/
  • New wallet created (not imported); recovery phrase written on paper and stored safely
  • A small test deposit before the full amount
  • The vault only receives: no DApps, no approvals, no signed messages
  • After any send: create a new wallet, back it up, move everything over

Please remember the only official website of MathWallet: https://mathwallet.org/

如何在去中心化钱包中安全存储大额资产（中文版）

日常使用的钱包追求的是方便：连接 DApp、签署授权、兑换代币，同一台手机上还装着各种应用。用来日常花销没有问题，但不适合存放你输不起的大额资产。

本文介绍一种简单的方法，用 MathWallet（一个私钥完全由你自己掌握的去中心化钱包）来存放大额资产。你只需要一台闲置的 iPhone，再加上纸和笔。

两个原则

下面所有步骤都围绕两个原则：

  1. 专用且始终保持最新的 iPhone。 这台手机除了这个钱包不做任何其他用途，并且每次使用前都升级到最新版 iOS。这是为了防范应用和系统层面的攻击。
  2. 只收款的钱包。 存放资产的钱包从未有过转出记录。一旦转出，就把剩余资产全部转到一个全新的、从未转出过的钱包。这是为了防范未来私钥背后的密码算法可能出现的漏洞，包括量子计算机的攻击。

第一步：准备一台闲置的 iPhone

  • 选一台你不再用于其他用途的 iPhone。它不能太旧，必须能升级到最新版 iOS。 苹果会公布每个 iOS 版本支持的机型；不在列表里的手机已经无法获得安全更新，不适合用来存放资产。
  • 从现在起，这台 iPhone 只做一件事：存储和管理你的大额资产。不要用它上网、聊天、收邮件或玩游戏，也不要借给别人。

第二步：抹掉手机并全新设置

  1. 打开 设置 > 通用 > 传输或还原 iPhone > 抹掉所有内容和设置。
  2. 手机重启后，设置为新 iPhone，不要从备份恢复，否则旧的应用和数据会一起回来。
  3. 设置一个强锁屏密码（6 位数字或更长的字母数字密码），并开启面容 ID 或触控 ID。
  4. 从 App Store 下载应用需要登录 Apple ID。建议为这台手机单独使用一个 Apple ID，设置强密码并开启双重认证。
  5. 关闭这台手机的 iCloud 云备份。你抄在纸上的助记词（第四步）就是你的备份。
  6. 打开 设置 > 通用 > 软件更新，安装最新版 iOS，并开启 自动更新。
  7. 不要安装任何其他应用。也不需要插 SIM 卡，只在更新系统或交易时连接可信的 Wi-Fi。

每个应用都是可能有漏洞、甚至本身就带有恶意的软件，多装一个应用就多一个入口。一台只有系统和钱包的手机，几乎不给攻击者留下可乘之机。

第三步：从官网安装 MathWallet

在这台 iPhone 上打开 Safari，访问 MathWallet 官网 https://mathwallet.org/，通过官网上的链接跳转到 App Store 安装 MathWallet。

不要直接在 App Store 里搜索后随手安装，也不要使用聊天、广告或陌生人发来的下载链接。仿冒的钱包应用确实存在，目的就是骗取助记词。

第四步：创建一个全新的钱包

  • 创建新钱包，不要导入以前的钱包。 用过的助记词或私钥经过了别的手机和应用，可能还进过剪贴板或云存储，你无法确定它从未泄露。
  • 设置一个强钱包密码，不要和其他任何地方的密码相同。
  • 把助记词抄在纸上。 不要截图、拍照，不要存进备忘录或网盘，也不要发给自己。把纸（最好抄两份）分别存放在安全的地方。如果这台 iPhone 丢失或损坏，这张纸是找回资产的唯一途径。
  • 可选但推荐：在转入大额资产之前，先验证纸上的助记词。在这台 iPhone 上删除钱包，再用纸上的助记词恢复，确认地址和之前一致。

第五步：转入资产

  • 收款地址一定要从这台 iPhone 的 MathWallet 中获取，不要从其他钱包或交易所的交易记录里复制。骗子会用外观相似的地址给你转一笔小额，让假地址混进你的交易记录（"地址投毒"）。核对完整地址，而不只是开头和结尾几位。
  • 先转一笔小额测试，到账后再转入其余资产。
  • 从现在起，这个钱包只收款。不要用它连接 DApp，不要签署任何授权或消息，也不要理会钱包里突然出现的陌生代币或 NFT，它们往往是钓鱼诱饵。

签名一条消息和发送一笔交易一样会暴露你的公钥，所以按照第二个原则，签名也算"转出"。

第六步：需要转出资产时

  1. 先升级 iOS。 连上 Wi-Fi，安装所有待更新的系统版本后，再打开钱包。
  2. 完成你需要的转出交易。
  3. 这个钱包已经有了转出记录，不再是"只收款"的钱包。在同一台 iPhone 的 MathWallet 中创建一个新钱包（使用新的助记词），并按第四步的方法把助记词抄在纸上备份。
  4. 把旧钱包里剩余的全部资产转到新钱包，每条链都要转。在以太坊及其他 EVM 链上，手续费用原生币支付，所以先转代币，最后转原生币。
  5. 新钱包就是你今后的"金库"。旧钱包不要再收款，之前保存过旧地址的地方（如交易所提币白名单）都要更新。确认旧钱包已清空后，可以把它从应用中删除。

如果你很少动用这些资产，这样做只是偶尔多付几笔手续费，换来一个始终干净的"金库"，很值得。

为什么这样做有效

原则一：干净且最新的手机，把攻击者挡在门外

大多数资产被盗并不是因为密码学被破解，而是被绕了过去：一个恶意应用、一个钓鱼链接，或一个尚未修补的系统漏洞，就可能拿到钱包的密钥。苹果会定期修复 iOS 的安全漏洞，其中一些在修复之前就已经被攻击者利用。一台保持最新、不装其他应用的手机，能关上绝大多数这样的门。

当苹果不再为你的机型提供更新时，就该让这台手机"退休"了：按同样的步骤准备一台更新的 iPhone，在上面创建新钱包，再把资产转过去。

原则二：从未转出的钱包，公钥始终不公开

私钥控制着你的资产，公钥由私钥计算得出。在很多链上，你的地址是公钥的哈希值（相当于公钥的"指纹"）。用今天的计算机，从公钥反推私钥实际上不可能做到。但是：

  • 量子计算机。 足够强大的量子计算机运行 Shor 算法，理论上可以从公钥算出私钥。没人知道这样的机器何时、甚至是否会出现，但大额资产往往一存就是很多年。
  • 签名实现的缺陷。 签名过程中的漏洞，比如有缺陷的实现中随机数不够随机，过去就曾让攻击者从链上公开的签名中恢复出私钥。

目前没有已知的方法能让量子计算机以同样的方式破解哈希函数。在很多链上，公钥只有在你签名时（无论是交易还是消息）才会公开。在此之前，别人能看到的只有你的地址，仅凭地址，攻击者无从下手。这就是为什么"金库"钱包从不签名，而一旦签了名，就要立刻清空到一个新钱包。

补充说明： 这层保护取决于链的地址生成方式。它适用于地址是公钥哈希的链，例如比特币 SegWit（bc1q…）和传统地址、以太坊及其他 EVM 链、TRON。在地址本身就是公钥的链上，例如 Solana、Polkadot 以及比特币 Taproot（bc1p…）地址，公钥从一开始就是公开的。存放 BTC 时，如果可以选择，长期存储更推荐使用 SegWit 地址（bc1q…）。

快速检查清单

  • 一台支持最新版 iOS 的闲置 iPhone
  • 已抹掉并设置为新 iPhone；未从备份恢复；没有安装其他应用
  • 已安装最新版 iOS，已开启自动更新
  • 通过 https://mathwallet.org/ 安装 MathWallet
  • 新建钱包（不是导入）；助记词已抄在纸上并妥善保管
  • 先小额测试，再转入全部资产
  • "金库"钱包只收款：不连 DApp、不签授权、不签消息
  • 每次转出后：新建钱包、备份助记词、转移全部资产

请记住 MathWallet 唯一官网：https://mathwallet.org/