How to overcome 'salt must be a byte string error'? - python-3.x

Question

Good morning,
I'm trying to recover my Multibit HD seed words using decrypt_bitcoinj_seed.py I don't know if anyone has used decrypt_bitcoinj_seed.py or not but I'm getting an error after it runs another python script in its arsenal called common.py with an error:
raise TypeError('salt must be a byte string')
There are many opportunities for errors to be thrown is this python script, so if this one is overcome there could be others to follow. (Please see code at the bottom.) The code below shows the salt error.
C:\Python38\decrypt_bitcoinj_seed-master>py decrypt_bitcoinj_seed.py
Traceback (most recent call last):
File "decrypt_bitcoinj_seed.py", line 319, in <module>
wallet = load_wallet(wallet_file, get_password)
File "decrypt_bitcoinj_seed.py", line 132, in load_wallet
key = pylibscrypt.scrypt(password.encode('utf_16_be'), salt, olen=32)
File "C:\Python38\lib\site-packages\pylibscrypt\hashlibscrypt.py", line 49, in scrypt
check_args(password, salt, N, r, p, olen)
File "C:\Python38\lib\site-packages\pylibscrypt\common.py", line 49, in check_args
raise TypeError('salt must be a byte string')
TypeError: salt must be a byte string
Does anyone know how the salt would be edited so it becomes a byte string or is there a better alternative? Also, not that it matters since I have very little programming knowledge, why does the script need all the following to crack the seed words? - password, salt, N, r, p, olen
The good news is the "check args" password script part passed. Here's the code I mentioned earlier about all the possibilities for errors to be thrown:
if not isinstance(password, bytes):
raise TypeError('password must be a byte string')
if not isinstance(salt, bytes):
raise TypeError('salt must be a byte string')
if not isinstance(N, numbers.Integral):
raise TypeError('N must be an integer')
if not isinstance(r, numbers.Integral):
raise TypeError('r must be an integer')
if not isinstance(p, numbers.Integral):
raise TypeError('p must be an integer')
if not isinstance(olen, numbers.Integral):
raise TypeError('length must be an integer')
if N > 2**63:
raise ValueError('N cannot be larger than 2**63')
if (N & (N - 1)) or N < 2:
raise ValueError('N must be a power of two larger than 1')
if r <= 0:
raise ValueError('r must be positive')
if p <= 0:
raise ValueError('p must be positive')
if r * p >= 2**30:
raise ValueError('r * p must be less than 2 ** 30')
if olen <= 0:
raise ValueError('length must be positive')
If other errors arise, I will post them here; but I'm hoping it will just work and return my seed words!

Answer 1

Prelude
I guess I've come up with the solution not to help myself only but to help someone one day. Had the same issue long time ago. As I understood from the question:
the main goal is to recover a seed (12-words phrase) which you will always need in order to restore your wallet and to get a full access to it, in particular sending funds (don't confuse with watch-only wallet mode like if you were using public key / wallet address to recover the wallet);
a solution does not have to be related with use of Python.
I dedicate this answer to all my brothers in misfortune who have wallets in MultibitHD which is no longer supported (Multibit is Deprecated - Do Not Use) and was abandonded with its unresolved issues like:
unconfirmed transactions;
frequent wallet repairing;
synchronization issues;
errors when entering the correct password;
backup failures etc.
Guide
We'll use the special utility which is stored as mbexport in npm (Node package manager) registry. Install mbexport package globally via npm which is installable with Node.js (npm install -g mbexport).
Next, you need to determine the path to the MultibitHD wallet file in your file system.
Generally, for Windows it is:
C:/Users/username/AppData/Roaming/MultiBitHD/wallet-id/mbhd.wallet.aes
For MacOS it is:
~/Library/Application Support/MultiBitHD/wallet-id/mbhd.wallet.aes
Where username is your Windows user, wallet-id is unique wallet identifier (starts with mbhd-)
A little hint: you can find out the path in MultibitHD application, if you can enter the wallet and know the password that you might have set. It's quite convenient especially when you have several wallets. Just navigate to Manage wallet -> Wallet dashboard.
Then you need to open a command prompt and enter the command below. path-to-wallet-file is the previously found path to the wallet.
Please note: I personally did not get the error Error opening wallet file only when I dragged the wallet file from the explorer right into the command prompt so that it became a full valid path. Also I recommend you turning off the Internet while getting the seed. Although I haven't found any issues in the source code of mbexport that dealt with sending sensitive data accross the Internet, it's a simple security matter.
mbexport path-to-wallet-file
Congratulations, you have finally got the seed! Don't share it with anyone and make sure you keep it in safe and wrote it on a physical paper as it is your key to your funds!
Restoring your wallet from the seed
Although it is not part of the question, you will probably want to know how you can restore your wallet with the seed, for example, in Electrum. Follow this guide Restoring your MultibitHD Wallet in Electrum and keep in mind that the seed you got is in obsolete BIP39 format, the derivation path in MultibitHD is m/0' and the type of address is p2pkh.