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~ Bitcoin Seed Phrases ~
Did you know you can store bitcoin in your brain?
All it takes is memorizing some words
In this thread I'll cover bitcoin mnemonic seed phrases and how they work
Did you know you can store bitcoin in your brain?
All it takes is memorizing some words
In this thread I'll cover bitcoin mnemonic seed phrases and how they work
2/ In bitcoin you control your coins by keeping a secret, called a private key
This is really just a large secret number, and you use it to authorize the transfer of funds
For more background on the details of private keys , check out my previous thread https://twitter.com/dannydiekroeger/status/1283928379201212416?s=20
This is really just a large secret number, and you use it to authorize the transfer of funds
For more background on the details of private keys , check out my previous thread https://twitter.com/dannydiekroeger/status/1283928379201212416?s=20
3/ If you've ever set up your own wallet, you've probably been prompted to write down some words and keep them secret, often 12 or 24 words
What are these words?
What are these words?
4/ These words are your private key!
Well, kind of... If you remember, your private key is a really large number, so how are these words also a number?
The trick is that these words encode your private key, using a process outlined in Bitcoin Improvement Proposal 39
Well, kind of... If you remember, your private key is a really large number, so how are these words also a number?
The trick is that these words encode your private key, using a process outlined in Bitcoin Improvement Proposal 39
5/ BIP39 was introduced in 2013, and it provides a strategy for representing private keys as a list of words
There are 2048 possible words in these lists, and each one maps to a number
You can see the English list here https://github.com/bitcoin/bips/blob/master/bip-0039/english.txt
There are 2048 possible words in these lists, and each one maps to a number
You can see the English list here https://github.com/bitcoin/bips/blob/master/bip-0039/english.txt
6/ The words were chosen such that no two words in the list are similar, and they are all basic words that are easy to remember
Each word maps to its position in the list, starting. at 0. For example:
abandon = 0
ability = 1
able = 2
about = 3
...
zone = 2046
zoo = 2047
Each word maps to its position in the list, starting. at 0. For example:
abandon = 0
ability = 1
able = 2
about = 3
...
zone = 2046
zoo = 2047
7/ Since each word maps to a number, you can look up each word in the word list to find it's number
Then by combining all those number together, you get a bigger number
Finally that number gets run through some rounds of hashing to produce your private key
Then by combining all those number together, you get a bigger number
Finally that number gets run through some rounds of hashing to produce your private key
8/ I won't cover the full details of the hashing cycles in that last step, but you can find them neatly outlined here: https://github.com/bitcoin/bips/blob/master/bip-0039/bip-0039-wordlists.md
9/ An interesting thing to note is that the last word in the list encodes what's called a Checksum
A Checksum is the first few bits of a Hash of the data and it's used to make sure you didn't type in the words wrong
Background on hashes: https://twitter.com/dannydiekroeger/status/1281100866871648256?s=20
A Checksum is the first few bits of a Hash of the data and it's used to make sure you didn't type in the words wrong
Background on hashes: https://twitter.com/dannydiekroeger/status/1281100866871648256?s=20
10/ In other words, if you type a word wrong or get them out of order, your software will detect it because it will invalidate the Checksum
That might sound a little bit complicated, but it will make more sense after we finish with this little demo...
That might sound a little bit complicated, but it will make more sense after we finish with this little demo...
11/ Check out this awesome website by Ian Coleman that helps you generate these seed phrases and breaks down the details
We're going to dive into the details
https://iancoleman.io/bip39/
We're going to dive into the details
https://iancoleman.io/bip39/
12/ Go ahead and select "12 words" and Generate, and you'll see some words show up
Your browser just generated a valid mnemonic seed phrase for you!
Your browser just generated a valid mnemonic seed phrase for you!
13/ Now lets go a little deeper.. Click the "Show entropy details" box and you'll see some crazy data pop up
Now take the first word in your list, and the first word in the "Word Indexes" section
Then search for your word in the word list at this link:
https://github.com/bitcoin/bips/blob/master/bip-0039/english.txt
Now take the first word in your list, and the first word in the "Word Indexes" section
Then search for your word in the word list at this link:
https://github.com/bitcoin/bips/blob/master/bip-0039/english.txt
14/ You'll notice they match! (almost.. they are off by one, because that number on the word list is the line number of the file, which starts from 1, whereas the word list indexes start from 0).
But you get the idea! You can check your other word indexes against the list too!
But you get the idea! You can check your other word indexes against the list too!
15/ Now I want to show you one more thing. Uncheck the "Show entropy details" box, and try swapping the order of the first two words in the list...
You'll see the software detects the error and says "Invalid Mnemonic" at the top
You'll see the software detects the error and says "Invalid Mnemonic" at the top
16/ This is the Checksum I mentioned earlier working to protect you
When you swap the order around, you change the number that your list encodes, which invalidates the Checksum at the end
Don't worry if that's too complicated - it's just a nice feature to help prevent mistakes
When you swap the order around, you change the number that your list encodes, which invalidates the Checksum at the end
Don't worry if that's too complicated - it's just a nice feature to help prevent mistakes
17/ Finally if you put your words back in order, you can then scroll down to find your private key.
The field is called Bip39 Seed - this is the outcome of that hashing I described earlier, and can be used as the private key for a new wallet
The field is called Bip39 Seed - this is the outcome of that hashing I described earlier, and can be used as the private key for a new wallet
18/ You might notice the seed is 512 bits, but a private key is supposed to be 256 bits..
The first 256 bits are your private key, and the second 256 bits can be used as something called a "chain code" for an HD wallet
But I'll save those details for a separate thread
The first 256 bits are your private key, and the second 256 bits can be used as something called a "chain code" for an HD wallet
But I'll save those details for a separate thread
19/ So let's summarize:
A mnemonic seed phrase encodes a private key, so that you can store bitcoin in your head!
Pretty neat, but why is this useful?
A mnemonic seed phrase encodes a private key, so that you can store bitcoin in your head!
Pretty neat, but why is this useful?
20/ Say your hardware wallet gets destroyed, or you need to flee your country and can't bring a hardware wallet with you
By storing and/or memorizing just a simple seed phrase, you are able to fully restore your wallet on a completely new hardware device!
By storing and/or memorizing just a simple seed phrase, you are able to fully restore your wallet on a completely new hardware device!
21/ But these seed phrases are a double-edged sword and must be protected diligently
If somebody finds your seed phrase, they can access your wallet and steal all your funds
So protect them and keep them secret!!!
If somebody finds your seed phrase, they can access your wallet and steal all your funds
So protect them and keep them secret!!!
22/ Finally, this Bip39 website is great, but you really should NOT be generating real private keys in your web browser if you intend to use them
When generating keys, you never want your device connected to the Internet, and you want to use a really good source of randomness
When generating keys, you never want your device connected to the Internet, and you want to use a really good source of randomness
23/23 We can dive into more strategies for proper key generation in another thread, so I'll end this thread here
Hope this was interesting. As always, please ask questions in the comments!
Hope this was interesting. As always, please ask questions in the comments!
And if you liked this thread, I have a bunch more!
Here's a link to a mega-thread with all my other educational threads: https://twitter.com/dannydiekroeger/status/1282000262782042117?s=20
Here's a link to a mega-thread with all my other educational threads: https://twitter.com/dannydiekroeger/status/1282000262782042117?s=20
