Bitcoin Q&A: Optional Passphrases (Advanced Security Feature) and Seed Storage

Do optional passphrases protect against leaks or compromises of mnemonic seed words? Why are brain wallets usually insecure? Why should you not "roll your own crypto" and promote creative schemes that deviate from the standards (like BIP39), without at least getting peer review and testing from other developers, cryptographers, or security researchers?

See the documentation and support pages of various hardware wallets for more information:

Chapters
0:00 Is it unsafe to publicly publish on Facebook or Twitter the twenty-four word seed, treating my passphrase as the thing that protects my assets in my hardware wallet?
5:24 Brain wallets
7:50 The most important rule in cryptography is, don't roll your own crypto.
10:45 I took my BIP-39 seed, cut it into twenty-four pieces, mixed them up, encrypted them, put them on Dropbox, then erased it from the web, and I can only access it on the archive.
12:36 Passphrase, does that mean the password on the hardware wallet?

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Andreas M. Antonopoulos is a technologist and serial entrepreneur who has become one of the most well-known and respected figures in bitcoin.

He is the author of two books: “Mastering Bitcoin,” published by O’Reilly Media and considered the best technical guide to bitcoin; “The Internet of Money,” a book about why bitcoin matters.

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[richardpickering]

We need clones of Andreas to replace a lot of the other so called crypto "experts" You are a much needed voice in this space, Thank you Andreas.

[camirov]

We must make it EASIER for common folks to understand and use

[margoomahony]

Aaaaand once again my brain expanded a little because I listened to you. Thank you for remaining a class act in a sector that seems to grow more phonies everyday.

[sys]

Andreas, I like the laid back camera angle. Nice

[edlearned]

Thank you! I've been trying to understand how a passphrase added extra security as many videos alluded to it being wallet centric. Understanding that is used in the generation of the private key now has the pieces falling into place.

[IgorRoztr]

Thank you Andreas for these amazing explanations.

[sansegkh]

Love the foreground and background. Much nicer to watch.

[petera]

Hi Everyone and as mentioned by Andreas, NEVER EVER Publish your seed and passphrase online. When you generate your seed, you should also do it, offline and do not share this seed with anyone. It should only be shared with people you trust (i.e.: the people you intend to pass on your Crypto, such as your next of Kin, etc) and it should be done with caution and indirectly (i.e.: using security strategies to gain the information when you have gone in the after-world).

[pachmann]

Thank you for this.
Question: if you are forced to open your ledger live, won't an attacker be able to see all your regular account's transactions and won't they display the movement of the bulk of your funds somewhere else (in this case, the passphrase account)?

[simonelof]

Oh lovely, some fresh content. Big things happening in crypto over here in Liechtenstein, let me know if you want to visit!

[johngrear]

If splitting 24 seed words in two is not secure, does this mean a wallet with only 12 seed word is not secure?

[compatibilizer]

Andreas, the standard is a piece of art in cryptography, unfortunately it includes some unfortunate wording... Today 90% of software wallets don't support the BIP39 passphrase, when developers read "optional" BIP39 passphrase, they think it is optional to implement into their software. Please, please pretty please, remove the word "optional" in the definition, just write "you can use empty string if you want" and that should be enough to prevent them skipping this very important feature, most fail to understand the value of it.

[davincij]

My question would be if BIP39 is a standard isn't it subjected to the standardized attack vector. So a hacker only needs to break BIP39 and has the ablity to attack all wallets in existance.

[barefootmillionaire]

this goes straight over my head, you are a genius but this is too hectic, lol

[EdwardCraven-sb]

I appreciate your efforts! 🙏 I wanted to ask something unrelated: 🤔 I only have these words 🤔. (behave today finger ski upon boy assault summer exhaust beauty stereo over). What is this? 🤔

[joac]

Would you consider using the same passphrase to create various seeds in different wallets a good practice?

How about using your full name as passphrase. This is just a substitute for the amnomic word and makes your seeds a bit different from all others generated right ?

[johngrear]

A passphrase is not just a brain wallet if you use a random source to generate the words, which of course you should be doing.

[mashtea]

Thank you Andreas, what if you have your 24 seed and added the passphrase but may have mistyped on the small trezor. I wrote down my passphrase and it is not working. So sad about this. Because I believe in the tech and have somehow messed up. From what I have gathered from this video if I have some of the words in my passphrase is there a tech (what is it called) to maybe run different combos of a space or a letter that was mistyped? I can see the funds but can not access them by typing in the passphrase or trying to send or receive using the passphrase.
Thank you inadvanced.

[bitcoinjustin]

Can you tell me lets say I keep my 24 word key secure and add a word for my passphrase. How secure would that second wallet be? Assuming they don't assume a 25th passphase and they dont have the 24 word seed?

[Francesco-cjoi]

In other words, just do some work, get your wallet as secure as possible, and don't worry about it unless you become an ultra millionaire