how to test decryption of shared seed for a multisig vault

Question

I used the script from this post

How to derive the private key associated with a Coinbase multi-sig vault address

To get the Master Private Key, Extended Private key at index 14, and WIF format of that key. All those values correspond to the user seed and user public key.
I need to do the same with the shared encrypted seed (and shared public key) but I am not sure I know the correct password used to encrypt the shared seed.
Looking at the coinbase multisig github they specifically state they used the BIP38 library to decrypt the encrypted shared key seeds.

Is there any way I can test passwords to decrypt the shared seed? I assume testing should de done offline, right?

Also, I have no idea what "Extended Private key at index 14" even means in this context. What does that mean?

Thanks in advance.

Answer 1

For anyone who is in the same boat, here is how I was able to test passwords on an encrypted shared seed.

Download the zip from Github Two-factor Bitcoin (BIP38) - Formerly at bit2factor.org; domain expired 4/5/2015 unzip it and open the index.html.
Disconnect from the internet before entering any data into the web page.
Select "Decrypt Private Key" Enter the encrypted private key and password you wish to test and click the blue "Decrypt Private Key" button.
If the Address and Private Key (WIF) display, you have the correct passphrase.