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Nunchuk Bitcoin Wallet

Latest release: 1.9.20 ( 25th October 2022 ) 🔍 Last analysed 15th December 2021 . No source for current release found
4.7 ★★★★★
26 ratings
1 thousand
11th November 2021

Jump to verdict 

Do your own research!

Try out searching for "lost bitcoins", "stole my money" or "scammers" together with the wallet's name, even if you think the wallet is generally trustworthy. For all the bigger wallets you will find accusations. Make sure you understand why they were made and if you are comfortable with the provider's reaction.

If you find something we should include, you can create an issue or edit this analysis yourself and create a merge request for your changes.

The Analysis 

On their description we read:

Compared with normal Bitcoin wallets, Nunchuk’s multi-user multisig wallet gives you two extra levels of protection. First, the use of multisig technology means that losing any one key will not compromise your bitcoin. Second, our multi-user features allow you to co-manage your bitcoin with your trusted ones, effectively reducing the burden of key management.

and

FULL DATA CONTROL

All data is stored on your local devices. With the provided backup, your wallet could be safely recovered anytime, anywhere. You have complete control over your keys, your funds, your data.

HARDWARE KEY COMPATIBILITY

Nunchuk supports all major hardware keys, including but not limited to: Trezor, COLDCARD, Keystone, Ledger, and BitBox02.

so this is a self-custodial Bitcoin wallet supporting multi-signature and it also functions as companion app for all major hardware wallets (or hardware keys as they quite rightfully call them).

Sadly they do have a “code” repository for mobile but use it only for its issue tracker. Without actual source code, this app is not verifiable.

(lw, em)

Verdict Explained

Without public source of the reviewed release available, this product cannot be verified!

As part of our Methodology, we ask:

No Source!

Is the source code publicly available?

If the answer is "no", we mark it as "No source for current release found".

A wallet that claims to not give the provider the means to steal the users’ funds might actually be lying. In the spirit of “Don’t trust - verify!” you don’t want to take the provider at his word, but trust that people hunting for fame and bug bounties could actually find flaws and back-doors in the wallet so the provider doesn’t dare to put these in.

Back-doors and flaws are frequently found in closed source products but some remain hidden for years. And even in open source security software there might be catastrophic flaws undiscovered for years.

An evil wallet provider would certainly prefer not to publish the code, as hiding it makes audits orders of magnitude harder.

For your security, you thus want the code to be available for review.

If the wallet provider doesn’t share up to date code, our analysis stops there as the wallet could steal your funds at any time, and there is no protection except the provider’s word.

“Up to date” strictly means that any instance of the product being updated without the source code being updated counts as closed source. This puts the burden on the provider to always first release the source code before releasing the product’s update. This paragraph is a clarification to our rules following a little poll.

We are not concerned about the license as long as it allows us to perform our analysis. For a security audit, it is not necessary that the provider allows others to use their code for a competing wallet. You should still prefer actual open source licenses as a competing wallet won’t use the code without giving it careful scrutiny.

The product cannot be independently verified. If the provider puts your funds at risk on purpose or by accident, you will probably not know about the issue before people start losing money. If the provider is more criminally inclined he might have collected all the backups of all the wallets, ready to be emptied at the press of a button. The product might have a formidable track record but out of distress or change in management turns out to be evil from some point on, with nobody outside ever knowing before it is too late.