Storing your Seed Phrase by "memorizing" it instead of "writing it down": Is it really safe, or does it just feel safe?

For those who use a Hardware Wallet, one of the most important things is storing the Seed Phrase, because the Seed Phrase is the information used to recover the Wallet and can be used to create the keys to access our digital assets.

The method most people prefer is to write the Seed Phrase on paper or a long-lasting material and store it in a safe place. But there is another idea that sounds interesting: "Don't write it down, but memorize the Seed Phrase."

The question is, is this method really safer than writing it down?

The short answer is no, it doesn't necessarily have to be safer, because memorizing a Seed Phrase doesn't eliminate risk, but rather changes the type of risk from "someone steals the backup" to "we might forget it or be unable to access the memory."

First, a Brain Wallet is not the same as memorizing a Seed Phrase

These two things are often mentioned together, but they are actually very different.

A Brain Wallet is the idea of using a message, word, or code chosen by a human as the initial information for creating Cryptocurrency keys.

The major problem is that humans often choose words or phrases with predictable patterns, such as names, birthdays, easy-to-remember phrases, or meaningful messages, allowing attackers to try a large number of possible messages.

In contrast, a Seed Phrase generated by a Hardware Wallet according to a standard like BIP-39 is created from cryptographically strong random data, not from a phrase created by the user.

Therefore, "memorizing a properly generated Seed Phrase" is not a Brain Wallet.

Why do people think memorizing a Seed Phrase is better than writing it down?

The reason is very easy to understand, because if the Seed Phrase is only in your head, there is no piece of paper or metal plate for someone to find and use to recover the Wallet.

Imagine someone breaks into your house to steal your belongings. If the Seed Phrase is written on paper and the perpetrator finds that backup, they can use that information to recover the Wallet on another device.

From this perspective, memorizing seems safer because there is no physical item to steal.

But the problem is that a Seed Phrase is not only at risk of being stolen.

The truth is, no method is risk-free

Memorizing a Seed Phrase reduces some risks, but introduces another type of risk.

If we write down a Seed Phrase, the main risk is that someone else might access the backup.

But if we choose to memorize it all, the main risks become forgetting it, misremembering it, mixing up the order, or being unable to access the memory in the future.

What many people overlook is that we have no guarantee that 10, 20, or 30 years from now, we will still be able to correctly remember all 12 or 24 words.

Accidents, age-related changes, or even stress and not using the information for a long time can make it more likely that we will misremember information we rarely use.

Is it really safe to memorize all 12–24 words of a Seed Phrase?

Technically, it is possible to memorize an entire Seed Phrase, and if you remember it correctly, you do not need to rely on a physical backup.

But the problem is that a Seed Phrase is not a password that you can press "Forgot Password" and reset.

If you misremember a word, the order, or are unsure which word is in which position, you may not be able to recover the original Wallet.

Importantly, the words you remember may seem correct, but when combined, they may not form the correct Mnemonic, or they may lead to a different set of Wallets than the one you want.

Therefore, relying on memory alone means placing all your security in human memory.

What if you only memorize part of it?

Another method some people use is to split the Seed Phrase into two parts, such as writing some words on a backup and memorizing the rest.

For example, suppose a Seed Phrase has 24 words. A user might store part of the words in a safe place and memorize the rest.

The advantage of this idea is that if someone finds only one part of the backup, they will not be able to use that information to recover the Wallet immediately.

But this method should not be considered "unpredictably safe."

If an attacker knows which words are stored and where the missing words are located, they can still try to generate possible word combinations, even though the number of possibilities is so high that a Brute Force attack is extremely difficult in practice.

In addition, the security of this method still depends on details the attacker already knows, such as the number of words, the positions of the missing words, and information about the Wallet being used.

Therefore, splitting a Seed Phrase and memorizing part of it should be viewed as "adding a layer of protection," not creating a risk-free system.

And another risk is forgetting the part you memorized

This is a very important point. Suppose we store 16 words of a Seed Phrase and memorize another 8 words.

If one day we can no longer remember those 8 words, the 16-word backup we stored may not be sufficient to recover the Wallet.

This means that this method does not eliminate risk, but rather splits the risk into two parts, and we must be sure we can maintain both throughout the lifespan of the Wallet.

What about a Passphrase, or the "25th word"?

Another method popular among Hardware Wallet users is to use a Passphrase in addition to a Seed Phrase.

Many people call a Passphrase the "25th word," but this term is just colloquial because a Passphrase is not actually the 25th BIP-39 word.

A Passphrase is additional information used with a Seed Phrase to create another set of Wallets or Accounts.

Therefore, the same Seed Phrase used with a different Passphrase can lead to a different set of Wallets.

For example, if you use the same Seed Phrase but change the Passphrase from "Example123" to "Example124," the result will not be the same Wallet.

This makes a Passphrase useful for those who want to add an extra layer of protection to their backup.

But a Passphrase also has drawbacks you need to know

The most important drawback is that a forgotten or misremembered Passphrase cannot be recovered like a password for a general service.

Even if the Seed Phrase is correct, if you use the wrong Passphrase, the device may open to another Wallet that appears to be empty.

Therefore, a Passphrase must be stored securely, and you should make sure you can actually recover the Wallet before storing a large amount of assets in a Wallet that uses a Passphrase.

Another important thing is that a Passphrase does not automatically protect assets in a Standard Wallet.

If the assets are still in a Wallet created from a Seed Phrase without a Passphrase, adding a Passphrase later will create another Wallet; it will not move the original assets into that Wallet.

If you really want to use a Passphrase to protect assets, you must store the assets in an Account or Wallet created from that Passphrase.

Should you write down or memorize a Passphrase?

The same principle as with a Seed Phrase still applies: there is no single answer that is right for everyone. If you choose to memorize the entire Passphrase, the risk is forgetting or misremembering it.

If you write down a Passphrase, the risk is that someone else might find that information. A better way is to store the Passphrase separately from the Seed Phrase and keep it in a place with appropriate access control.

Importantly, you should not take a photo of the Seed Phrase or Passphrase and store it on your phone, in email, Cloud Storage, or on an internet-connected computer, because making a digital copy creates additional ways for sensitive information to leak.

So, what is a better way to store a Seed Phrase?

For most people, a better approach is often not choosing "memorizing" or "writing it down" alone, but creating a backup system that reduces both the risk of theft and the risk of data loss.

A Seed Phrase should be stored offline and not connected to the internet. Use a more durable material, such as a Metal Backup, to protect against damage from fire, water, or the aging of paper.

If you make more than one copy, you should store them in safe and separate places as appropriate, rather than keeping all copies in one place.

But you must be careful about one important thing: "having multiple backups" does not mean we should let multiple people know the Seed Phrase, because everyone who knows the Seed Phrase has the opportunity to access the Wallet.

Don't forget about asset succession

Another question you should ask yourself is, if an event occurs where we can no longer access the Wallet, who will be able to recover the assets?

If we are the only one who knows the Seed Phrase and remember everything in our head, the system may be safe from theft today, but it will create problems in the future if we cannot pass the information on to the person who needs to use it.

Therefore, backup planning should consider both Security and Recovery, including the transfer of assets in case of emergency or inheritance.

Can Multisig help?

Multisig is another approach for those who hold a large amount of assets and want to reduce reliance on a single set of backups or keys.

The basic idea is to require multiple sets of keys to be used together to approve a transaction, such as a 2-of-3 system requiring 2 out of 3 keys to spend funds.

The advantage is that losing one set of keys does not immediately result in the loss of assets, and an attacker obtaining only one set of keys may still not be enough to steal the funds.

However, Multisig is more complex than a regular Wallet and requires proper planning for Backup, Key Management, and Recovery, making it suitable for users who understand the system and are ready to manage it seriously.

In summary, is memorizing or writing it down safer?

Memorizing a Seed Phrase may help reduce the risk of someone finding a physical backup, but it does not mean it is safer in every situation.

In contrast, writing down a Seed Phrase and storing it in a safe place may carry the risk of discovery, but it can reduce the risk of forgetting or misremembering.

For most users, a better approach is to store an Offline Backup in a safe place and design a system that can actually be recovered in the long term.

If you want to add Security, you can consider a Passphrase, or in cases of extreme complexity and very high value, you may consider Multisig, but every method has a Trade-off, and you must understand your own Recovery method before actually using it.

Ultimately, the more important question than "memorize or write it down?" is "If something unexpected happens today, will we still be able to properly recover the wallet?"

Because the most secure system is not one that no one can steal, but one that can prevent unauthorized access while still allowing the owner to recover their own assets when necessary.