"Don't worry about mnemonic phrase leaks" ? Understand how to use wallet Passphrase in one article

Summary: Passphrase can ensure that assets remain secure even if the mnemonic phrase is “leaked.”

In most users’ understanding, the mnemonic phrase is the “ultimate key” to an encrypted wallet: whoever has the mnemonic phrase controls everything in the wallet.

This statement is correct in most cases, but it is not complete. Because beyond the mnemonic phrase, there is actually an even more “extremely secure” layer of design—the Passphrase.

If we were to summarize its role in one sentence, it would be: Passphrase = “brain wallet” + “mnemonic wallet” double buff.

It is not meant to replace the mnemonic phrase but to add an extra lock that exists only in your mind, providing an additional layer of security when facing “real-world risks.”

Starting with an intuitive analogy: why is relying solely on the mnemonic phrase not enough?

The security model of the mnemonic phrase essentially states: whoever controls the mnemonic controls the assets.

This model is very effective against online attacks and remote hackers, but it has a natural shortcoming in the real world: the mnemonic phrase is “something that can be physically obtained”—written on paper, engraved on steel, or taken out and photographed.

This is why, in security circles, an extreme but real scenario is often discussed: when an attack does not happen on-chain but in real life, the mnemonic phrase itself becomes vulnerable.

Passphrase exists precisely for this scenario. It is not a feature exclusive to a particular type of wallet but a universal security mechanism built on top of the mnemonic phrase. Whether used with software wallets or hardware devices, the underlying logic of Passphrase remains the same; the only difference is the level of security boundary. In practical use, this mechanism is often first encountered in “software wallet” form. For example, with the SafePal App, you can enable Passphrase when creating a new wallet:

Core logic of Passphrase: adding a “memory lock” on top of the mnemonic phrase.

Technically, the role of Passphrase is very simple, but its effect is extremely “counterintuitive.” The same set of mnemonic phrases, when entered with or without the Passphrase, will generate completely different, independent wallet accounts.

You can understand it this way:

Only mnemonic → a “default wallet”

Mnemonic + Passphrase → a completely new “hidden wallet”

Moreover, as long as the Passphrase is different—even just one character—the generated accounts are entirely different.

Once you understand this, it becomes more intuitive to see how it performs in higher-security scenarios. When combined with hardware wallets, this security model’s boundary is further expanded. This is also why Passphrase is most often used for long-term holdings or high-value asset management. For example: you generate a mnemonic offline with the SafePal X1 and securely store it on a hardware device; then, you set a Passphrase known only to yourself, such as SFLRW,HKJZ (“The heroes of the times still look to today”), entering a completely different account space.

(Address without Passphrase, address with Passphrase)

Additionally, this string itself does not need to look “good” or be understood by anyone; as long as it exists only in your memory, the wallet derived from it can only be accessed by you.

Why is it called a “double buff” of “brain wallet + mnemonic wallet”?

If we look at the previous discussion from the same security mainline, hardware wallets solve one problem: private keys and mnemonics do not contact the online environment, reducing the risk of remote attacks.

Passphrase addresses a completely different dimension: even if the physical carrier is taken away, assets remain inaccessible.

When combined, the security model undergoes a qualitative change:

Hardware wallets provide physical isolation

Passphrase provides memory (mental) isolation

Passphrase does not exist on the device, on paper, or in any mnemonic backup. It only participates in the derivation process briefly at the moment of input.

This means a very critical result: even if someone obtains your hardware wallet and knows your PIN, without the Passphrase, they cannot access the hidden account.

Where does Passphrase’s value in the real world show?

Understanding the value of Passphrase often starts not from “technical principles” but from usage scenarios.

For long-term holdings or high-value assets, it at least solves three practical problems.

First, hedging against the risk of mnemonic leakage. Even if the physical backup of the mnemonic is photographed or stolen, the truly important assets can still be stored in the Passphrase wallet, not exposed at the same risk level as the “original account.”

Second, privacy and boundary control. Even if family or friends legally access the device itself, without the Passphrase, they cannot see or operate the hidden account.

Third, flexibility in asset management. With different Passphrases, you can create multiple logically independent accounts under the same mnemonic, suitable for long-term storage, daily use, or isolating assets of different risk levels.

From this perspective, Passphrase is not about making wallets “more complicated,” but about making the storage of high-value assets more akin to real-world safes.

But one point must be clarified: Passphrase is not suitable for everyone.

Many people might be tempted to think: “Should I immediately add a Passphrase to my wallet?”

The answer is: not necessarily, and many beginners are not suitable.

The reason is simple and harsh—if you forget the Passphrase, there is no way to recover it.

It is not stored by Web3 wallets, nor can it be “retrieved” or “reset.” Entering the wrong Passphrase will not prompt an error but will create a completely new, empty wallet. In the real world, many users have lost assets permanently not because of hacking but because they forgot the Passphrase.

Therefore, Passphrase is more like a “high-risk, high-reward” tool:

It can greatly increase security limits

But at the same time, it also maximizes the cost of operational mistakes

Final note: The right mindset for Passphrase

To sum up its role in one sentence: it is not a “standard” feature of encrypted wallets but an “advanced option” for a very small minority.

Before deciding to use it, you should ask yourself: three or five years from now, without any hints, can I still remember it accurately?

If the answer is no, then perhaps avoiding the Passphrase is actually the most responsible choice for your assets.