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Zumo: Buy Bitcoin & Ether

Latest release: 4.5.2 ( 25th January 2023 ) 🔍 Last analysed 12th October 2020 . No source for current release found
10 thousand
28th October 2019

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

As part of our Methodology, we ask:

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.

Help spread awareness for build reproducibility

Please help us spread the word discussing transparency with Zumo: Buy Bitcoin & Ether  via their Twitter!

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 

💰 Provides full ownership of funds - your crypto is only owned by you!

sounds like non-custodial but

👮 Accounts are activated after an ID check!

doesn’t. Then again

📵 Lost your device? Reinstall, Login, & use your Backup Phrase to regain access

says something about “Backup Phrase” but if you have to “Login” first, we wonder if that backup phrase is shared with a server or if it is a BIP39 mnemonic at all.

Your Private Keys are managed on device, crypto currency is stored securely on the blockchain, and all of our codebase is developed in-house.

Again, this does not say anything about the keys being exclusively being on the device. Also what is that claim about the codebase? Well, let’s see …

As a non-custodial wallet, all your crypto is stored on the Blockchain.

Now that is explicit. Let’s see if there is public source code available …

… but we can’t find anything on Google Play or their website. The verdict is thus: not verifiable.