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利用開始

Ledger入門

PATHWAY 2. 暗号資産を保護する方法

chapter 3/4

シークレットリカバリーフレーズとは?

読む 6 min
Beginner
シークレットリカバリーフレーズは、暗号資産ウォレットに保管されているすべての秘密鍵のバックアップです。
重要なポイント:
— Your Secret Recovery Phrase (or seed phrase) is the backup of all the private keys stored in a given crypto wallet. It allows you to recover all of your blockchain addresses, even without the original crypto wallet.

— This 12-24 word phrase must be kept secure- it’s vital to never enter it into a computer or smartphone and to never share it with anyone as it allows anyone to restore your entire wallet.

— Your seed phrase is the most sensitive piece of data: You must write it down correctly, otherwise you may lose access to your wallet.

暗号資産は、セルフカストディと呼ばれる自己管理が基盤となります。従来の銀行とは異なり、資産の所有権を取得できるのです。 その一方で、個人の責任もより大きくなります。 秘密鍵を保護することと、ウォレットへのアクセスを維持することは別のことです。 現在、無数の休眠中のビットコインウォレットが存在していますが、それらはアカウントにアクセスできなくなった人々が多数存在することを意味しています。

That’s why backing up your crypto wallet is so important. Who knows what challenges your backup may face, from loss or theft to natural disasters?

もっと効率よく暗号資産ウォレットのバックアップを保管しませんか?

Well, the answer lies with something you may be familiar with if you already have a crypto wallet: your Secret Recovery Phrase, also known as a seed phrase.

In short, it lets you restore an entire crypto wallet on a new device or interface—along with all of the accounts associated with it. But there’s a bit more to it than that. Let’s dive in:

What is a Seed Phrase?

A seed phrase, also known as a Secret Recovery Phrase (SRP) or mnemonic, is simply a collection of words that allows you to restore your entire crypto wallet. It’s those 12-24 English words that your wallet presented you with while setting it up. If you followed its instructions correctly you should have recorded these words in order somewhere.

This simple sequence is similar to a master key for your private keys. To explain, your wallet uses it to generate private keys for multiple networks and accounts. This is how you can restore the entire wallet with that single seed phrase.

しかし、正確には何のためにあるのでしょうか?

What is a seed phrase for?

A seed phrase is simply for providing a backup of your wallet should it become unusable via theft or destruction. Perhaps your wallet got stuck in the washing machine. Or perhaps you were relying on a software wallet on a laptop that doesn’t work any longer. Alternatively, you might just want to change which wallet you use.

In these cases, a seed phrase gives you the option to restore the entire wallet on another device or interface. To explain, your crypto is not in your wallet itself, but on the blockchain. The wallet simply protects the private keys connecting you to those blockchain addresses.  As long as your recovery phrase is the same, the calculation of the private keys will always have the same result—giving you access to all of the accounts connected to that mnemonic.

新しいウォレットを設定するときは、新しいウォレットを設定するか、リカバリーフレーズから復元するかを選択できます。 後者を選択した場合、12 ~ 24単語を入力して、そのウォレット全体を新しいデバイスまたはインターフェイスに復元できます。 これは、元のウォレットプロバイダーがもう存在しない場合でも、互換性のある別のウォレットに単語を入力してアクセスを復元できることを意味します。(セキュリティ面の理由から推奨できない場合もあります)。

But before we get there, let’s explore how a seed phrase works, and how it’s able to do this.

How Do Seed Phrases Work?

It’s important to note your recovery phrase doesn’t start off as a set of words. It’s actually just a translated version of a long string of numbers called the entropy. However, the entropy is so long that it’s very impractical to record. To solve this problem, Bitcoin Improvement Proposal 39 (BIP-39) introduced a standardized method to translate that long number into something more easily recorded by a human. Using this method, there are a total of 2048 English words that your seed phrase may use to translate the entropy. 

それが長い数値の単なる直訳である場合、どうしてシークレットリカバリーフレーズを安全と言えるのでしょうか? 実際には、エントロピーの生成方法が大きく関わっています。 エントロピーは非常に長くてランダムでなければなりません。誰かがそれを推測できる可能性があるためです。 エントロピーがランダムに選択され、128ビット以上で構成されている限り、十分に安全であり、人やコンピューターがそれを解読することはできません。

Ledger Secret Recovery Phrases (Seed Phrases) Explained

Ledgerデバイスは乱数ジェネレーター (RNG) を使用してエントロピーを生成するため、極めてランダムな組み合わせとなります。 さらに、すべてのLedgerデバイスは、24単語のリカバリーフレーズを使用しており、これは256ビットのエントロピーに変換されます。これは十分な長さを持ち、組み合わせを推測することは不可能です。

Ledgerでの生成プロセスは次のように行われます。

  1. Ledgerデバイスの電源を入れる。
  2. Set a personal PIN code
  3. デバイスはランダムな長い数値、別名を生成します。エントロピー
  4. The entropy is translated into your Secret Recovery Phrase (seed phrase) using BIP-39
  5. The Secret Recovery Phrase (seed phrase) is displayed on your Trusted Display

If you ever receive a device containing a pre-completed Secret Recovery Phrase or PIN code, do not use the device! It may mean that the device is pre-owned, or possibly even tampered with. Under these circumstances, contact Ledger customer support for more information.

How Can I Keep My Seed Phrase Safe?

So, now you know that your seed phrase is a backup to all of your crypto wallet. This also means that if anyone else can get their hands on your set of 24 words, they can access your cryptocurrencies. As such, it’s extremely important to keep your seed phrase secure. So what can you do to protect it?

必ず正しく記録する

Firstly, you want to make sure you write down or record your seed phrase correctly. Any error in spelling or word order would cause a different set of addresses to be generated. To lend a hand with this, Ledger has developed a dedicated application. The Recovery Check app lets you check if the recovery phrase you wrote down matches the one protecting your device. Easy!

オフラインで保護

Next, you should never store your SRP on cloud-based services. If the server is hacked, your seed phrase—and therefore your wallet—could become compromised. Similarly, you should never transact while using software wallets on devices using shared wifi networks. You wouldn’t want to share your seed phrase with everyone on the airport wifi, would you? Well, keeping a copy of your seed phrase on an internet-connected device is asking for exactly that. 

Recording your seed phrase on something physical— be that a hardware wallet or a piece of paper—is a much better option.

At this point, it’s important to mention that you should never restore your hardware wallet’s seed phrase into a software wallet. To explain, the entire point of a hardware wallet is that it generates your seed phrase completely offline. This means not even the most sophisticated digital spyware could see those words. If you enter that same secure recovery phrase into a wallet that doesn’t have those same qualities, you risk exposing it. In short, if you import your hardware wallet into a software wallet, your secret recovery phrase might be vulnerable to online threats.

盗難、事故、自然災害から保護してください。

To follow, you should also bear in mind where you store your SRP physically. If someone steals your SRP sheet, they can easily access your wallet. Thus, no one should know your secret hiding place—not your mom, not your wife, and certainly not your housemates. In the cases where you have no safe place to store your seed phrase, you may be interested in Ledger Recover. The paid optional service allows users to back up their seed phrases by fragmenting and distributing them to custodians. In short, this removes the burden of protecting your seed phrase at home.

Then, of course, sometimes losing your seed phrase is more of an accident. For example, what happens if your house burns down and your seed phrase is stored on a piece of paper inside it? To protect against these types of disasters, a great option is the BillFODL. This type of physical storage is very resistant to potential damage—and sleek at the same time.

Never Share Your Seed Phrase With Anyone

And of course, the final piece of advice is never to share your 24-word recovery phrase with anyone – not even with Ledger. We will never ask for it, nor should anyone else. Remember: you are the final barrier to your assets. Don’t let your guard down, as bad actors will try to socially engineer you into revealing your seed phrase. Not your keys, not your coins: if someone has access to your SRP they have all of your keys.

Your Seed Phrase: A Necessary Wallet Backup Tool

So, now you know all about seed phrases; from what they are to how they work, to how to protect yours effectively. But that’s not the end of your security journey. The ultimate guardian of your Secret Recovery Phrase is you.

Luckily, the Ledger ecosystem offers plenty of options to keep your seed phrase safe. Whether you want to check you’ve recorded the correct mnemonic, find a more permanent storage solution, or even use Ledger Recover, Ledger offers an option that works for you—without losing custody of your assets.

セルフカストディに妥協するなら、なぜ暗号資産を使う必要があるのでしょうか?


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