How do I identify the valid checksums for bip39 if I generate 11/12 of the word?

[hosseinimr93]

The correct checksum is 0001, so the last word is 11111000001.

The correct checksum is 1001 and the last 11 bits are 11111001001.
I think you made a typo, because the last word is still "Weird" and your final result is correct.

[1715138225]

1715138225

[1715138225]

1715138225

[1715138225]

1715138225

[BitcoinCanSaveUsAll]

Thanks all.  So if I'm getting this right and I wanted to simply create my own independent entropy for a BIP 39 12 word seed, I can do it by performing the following steps:

1)   Take 128 bit entropy (i.e. 11 randomly selected BIP 39 words and identifying their 11 bit codes + 7 random bits - or perhaps just 128 coin flips).
2)   Convert the binary 128 bit string to hexadecimal.
3)   Perform a SHA 256 hash of the hexadecimal.
4)   Convert this SHA 256 hex digest to a binary number and take the first 4 bits of this binary number output as the checksum.
5)   Append the checksum identified in step 4 to the entropy from step 1 and deconstruct the 132 bits into 12 groupings of 11 bits to get the BIP 39 12 word lists.

Alternatively I imagine I could simply roll a16 sided dice to get 32 unique hex values and skip steps 1 and 2 but would need to add a step between 4 and 5 above to convert the hex I rolled into binary to append the checksum.

That all said, can anyone here give me some insight with how I would perform steps 2 and 3 on a windows box (ideally offline)?

[BlackHatCoiner]

2)   Convert the binary 128 bit string to hexadecimal.
3)   Perform a SHA 256 hash of the hexadecimal.

You don't hash the hexadecimal, and that's why you don't need to convert the binaries to hexadecimal. Hash functions take input as bytes. You need to convert your 128-bit string to bytes, and then hash that. It's just that most libraries do this conversion in the background, which brings some confusion.

Alternatively I imagine I could simply roll a16 sided dice to get 32 unique hex values and skip steps 1 and 2

Note that a 16-side dice is likely to be more prone to return less random results than a 6-side dice, and even less than a 2-side coin. You should run a chi-squared test, to check this.

That all said, can anyone here give me some insight with how I would perform steps 2 and 3 on a windows box (ideally offline)?

Windows box? You mean Windows Forms in Visual Studio?

[BitcoinCanSaveUsAll]

Hi BlackHatCoiner,

Thanks for the tips.  When you stated "You need to convert your 128-bit string to bytes, and then hash that. It's just that most libraries do this conversion in the background, which brings some confusion" Do you have any suggestions on the best way to do this in an offline Widows machine?

Also, when you asked "Windows box? You mean Windows Forms in Visual Studio?" I simply meant a Windows PC.  Thanks.

[BlackHatCoiner]

Do you have any suggestions on the best way to do this in an offline Widows machine?

Hash bytes? Sure, but there are programs that let you make a seed yourself completely, not just for this part. That's one I've written: https://github.com/AngeloMetal/CoinFlippedSeed

Also, when you asked "Windows box? You mean Windows Forms in Visual Studio?" I simply meant a Windows PC.  Thanks.

The above program works on Windows.

[BitcoinCanSaveUsAll]

Thanks but the idea here was for me to learn how to do as much as possible myself and to avoid putting trust in any particular software relating to building your own bitcoin wallet offline.  That said, can you give me a walk through on how I would do that step manually on windows?  TY

[BlackHatCoiner]

Thanks but the idea here was for me to learn how to do as much as possible myself

Building the software from scratch requires a certain degree of technical competence. If you don't feel confident with that, I strongly recommend you to either use code that isn't yours and that you've read it, or study software engineering until you do feel confident enough.

That said, can you give me a walk through on how I would do that step manually on windows?  TY

First of all, I want to make it clear that I don't want you to trust me. I want you to verify me. The code isn't difficult to read. Most of it happens in Form1.cs. I make use of the NBitcoin and Bitcoin.Net libraries which are broadly used in other software too.

There are two ways to execute this program. One's to import the source code in Visual Studio 2019, and then have it compiled. The easier way is to download CoinFlippedSeed-v0.3.zip, make sure that the SHA-1 of the zip is 4DA93F3D72A9EB65282650E15D4E3C288A28FD71*, unzip the binaries and run CoinFlippedSeed.exe.

*You can try to skip the integrity verification part (that is the SHA-1 verification) for the moment, just to try out the software, but it's important to do it regularly on most of the software you install. It makes sure that the binaries aren't compromised. Do it if you're about to create a Bitcoin wallet with funds deposited.

[BitcoinCanSaveUsAll]

Thank you again BlackHatCoiner.  I certainly appreciate all of your replies.  That said however I am not a coder and not presently looking to be one but rather someone who likes to tinker with bitcoin and is trying to get to the point where I can create my own entropy and generate my own BIP 39 seed word without any reliance on the available software that does it. The idea is that as a non coder that can't verify code independently (and even if I could, I am not an encryption expert to fully understand all the intricacies there).

That all said, I feel I'm right on the cusp of knowing how to build my own BIP 39 seed word list for use an offline wallet that uses this standard and PSBT files that is compatible with Bitcoin core.  In my mind this is probably one of the safest ways to transact with sovereignty and that's what I'd like to be able to achieve here.   I'm just getting stuck in a few areas being a non coder windows user.  I can easily create my own entropy and understand that I need to be able to figure out how to perform some of the steps that yo mentioned here:

"You don't hash the hexadecimal, and that's why you don't need to convert the binaries to hexadecimal. Hash functions take input as bytes. You need to convert your 128-bit string to bytes, and then hash that. It's just that most libraries do this conversion in the background, which brings some confusion."

As far as how to convert my 128 bit entropy to bytes, I understand that would mean just simply deconstructing it to 8 bit chunks.  However specifically how to structure those bytes into a file format that I can use a built in Windows tool. I think my method of execution is off as I was apparently wrong in saving the ones and zeros in a notepad.txt file format.  So if I understand you right, then what I need to do is somehow create a binary file of my entropy.  I'm wondering how I would go about that and that once it's done, how I would then structure the binary file to contain the bytes to be digestible by the SHA 256 hash function that I'm hoping is possible with a build in windows tool.

Thanks.

[o_e_l_e_o]

i.e. 11 randomly selected BIP 39 words

Again, please don't do this. It isn't secure, like, at all.

Alternatively I imagine I could simply roll a16 sided dice to get 32 unique hex values

I wouldn't use dice at all. Dice are more prone to bias than coins, the bias takes longer to detect, and is also harder to detect. All of these things become more true the more faces your dice has. It would take hundreds of rolls to be relatively sure of detecting even a fairly large bias on a 16 sided dice. It will be simpler, quicker, and more secure to flip a coin 128 times.

[BlackHatCoiner]

That said however I am not a coder and not presently looking to be one but rather someone who likes to tinker with bitcoin and is trying to get to the point where I can create my own entropy and generate my own BIP 39 seed word without any reliance on the available software that does it.

Okay, but note that you do rely on lots of things that I'm not sure you're aware of. First of all, you rely on Microsoft. There's absolutely no way to prove that your OS won't betray you, unless Microsoft released the source code and let developers across the world confirm they haven't inserted a backdoor. Secondly, there's a higher chance that your OS has a 0-day, compared to Linux, because it isn't so broadly reviewed. Thirdly, you rely on software developers, cryptographers, and mathematicians.

But, yes. You do avoid the firmware RNG.

However specifically how to structure those bytes into a file format that I can use a built in Windows tool

With coding. But since that's not your field, I recommend you to use my software. Otherwise, tell me exactly what you want to do. You might be a victim of an XY problem.

[BitcoinCanSaveUsAll]

Hi BlackHatCoiner / all,

I agree there are several software items I am trusting.  The trick I'm trying to pull off is minimizing my sphere of trust to only encompass the essentials and of course as you said avoid the RNG.  That said I'm only interested in performing the OS stuff relating to generating the BIP 39 in an offline machine that will never see the internet which should help reduce that trust further. 

As to what I'm ultimately trying to do is figure out exactly how best to take my own derived entropy that I create offline and then create a 12 word BIP 39.  To me it sounds like flipping a coin 128x or rolling dice is the way to go (at least for testing).  Where I get confused is once I have that 128 bits (ones and zeros) what exactly do I do in Windows to:

1) identify the Hex value for the 1s and 0s of the entropy (offline), and then

2) once I have the Hex value, how do I perform a SHA256 hash for this Hex value in windows (offline) in the hex value of the entropy so I can then convert the first value of this SHA256 digest value back to binary (first 4 bits) to get the checksum that I would need to append to the 128 bits of entropy.

TIA

[BlackHatCoiner]

Have you tried out my software? You're not going to mess with hex values, hash functions and mnemonic standards at all. That's technical stuff that happens on the background. You'll just flip a coin, and submit the results. Once done, it'll return you your BIP39 seed phrase, as well as some addresses of every type (legacy, nested segwit, native segwit) with their responsive private keys.

Alternative to my software (and more reviewed): https://iancoleman.io/bip39/

[BitcoinCanSaveUsAll]

Hey, no not yet. However the whole thing for me here is that I want to understand what's occurring in the background and how it happens so that I can learn for myself and be comfortable with what's going on and why.

If anyone out there can help me out with suggestions on what programs / commands I can use built in Windows offline that will allow me to convert my 128 bit entropy to a hexadecimal number and then also perform a SHA 256 on the hexadecimal output it would be very helpful. Thank you.

[pooya87]

Windows is very limited in using commands and stuff like that to compute hashes, etc. Linux is better. But in any case it is a lot better if you learn and use a programming language instead of trying to make it work with commands. Something like Python is easy to learn and you can use it for such purposes, not to mention there are many open source projects on github.com in python you can use.

[o_e_l_e_o]

I also don't use Windows, but a quick internet search seems that there is no obvious way to use Windows Powershell to compute the hash you need. If you were running Linux, then you just open terminal and enter the following very simple command:

Code:

echo -n "11110010101100010111001111000101110101011010101011111111111010111011100000000100001001011111111101011111111000100000010101111100" | shasum -a 256 -0

Which will return the following output:

Code:

931258d717865a310cfc24a9161b21f4c0d02e0bb4cf12894516170a10e72339

And then you take the fist character (9) and convert it to 1001 and append as your checksum.

Here's another open source tool you can use to input your coin flips and generate your seed phrase: https://bitcointalk.org/index.php?topic=5373505.0

[BitcoinCanSaveUsAll]

Hmm you all may end up forcing me into the world of Linux and python after all.  Either way I'm going to first try to enable to turning on Windows Subsystem for Linux just so I can try to run those commands as you mentioned.  I'll give this a try and report back.  Thanks!

[BitcoinCanSaveUsAll]

Update:  I've installed both Debian and Kali for Windows and upgraded both distros.  That said when entering your command it seems as though the windows version of linux does not recognize shasum as the output states the following:

└─$ echo -n "hello world" | shasum -a 256 -0
-bash: shasum: command not found

Perhaps these versions don't include the shasum command?  Or perhaps the Windows versions don't?

Either way any suggestions on this issue or also any recommendations on any specific Linux distributions that can let me perform the above would be appreciated.  Thanks.

[BlackHatCoiner]

-bash: shasum: command not found

I've had problems with shasum in the past. Try sha256sum:

Code:

echo -n "hello world" | sha256sum

This will return you the SHA256 hash of the bytes of "hello world":

Code:

b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9  -

I'm not sure what o_e_l_e_o's command does. To me, echo -n "hello world" | shasum -a 256 -0 is executed normally, but it gives another result:

Code:

$ echo -n "hello world" | shasum -a 256 -0
e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 ^-

Edit: -0 means that it reads in bits mode. So, I presume that it treats the input as binary, and converts it later to bytes to hash it.

[o_e_l_e_o]

Perhaps these versions don't include the shasum command?  Or perhaps the Windows versions don't?

Again, I have absolutely no idea about Windows, but on a pure Linux machine you could try the following command to install the necessary packages. It may or may not work on your Linux for Windows:

Code:

apt-get install libdigest-sha-perl

I've had problems with shasum in the past. Try sha256sum

sha256sum won't work in this case, because it does not have an option to treat the input as bits.

I'm not sure what o_e_l_e_o's command does. To me, echo -n "hello world" | shasum -a 256 -0 is executed normally, but it gives another result

-a selects an algorithm, in this case 256. -0 tells it to read the input as bits, which is necessary when computing a checksum as above.

[BlackHatCoiner]

sha256sum won't work in this case, because it does not have an option to treat the input as bits.

My bad. I'm thinking in terms of hexadecimal. You can append the 128 bit number with a "9" and then convert the 132 bit number to ones and zeroes, can't you?