This app was first launched on 25th September 2017 and currently has more than 100000 downloads, a 4.1 stars rating from 1323 users and the latest APK (version 2.6.1) was from 21st January 2020 and is newer than the below reviewed version of the app.
We found these ways of contacting the developers:
Help spread awareness for build verifiability
Please help us spread the word, asking Eidoo: Bitcoin and Ethereum Wallet and Exchange to support verifiable builds via their Twitter!
The following Analysis is not a full code review! We plan to make code reviews available in the future but even then it will never be a stamp of approval but rather a list of incidents and bad coding practice. We cannot find and tell you all the dark secrets the wallet providers might have.
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.
The app’s description sounds non-custodial as it mentions an HD backup:
Eidoo is a multicurrency wallet and a crypto exchange with a single backup passphrase and HD security level.
The website is more explicit:
Your private key is encrypted on the app and only you can decrypt it as Eidoo is NOT a custodian wallet. You can use the wallet without providing any personal information
Unfortunately we can’t find any source code. No such link on their website and
neither can we find any relevant hit searching for their appId
When restoring a wallet from the 12 words mnemonic, the wallet uses the currently active keyboard which might be less than trustworthy. More secure wallets have their custom keyboards for backup entry.
The wallet also is limited to 12 words + passphrase and does not support 24 words as some wallets use by default, so you won’t be able to use this wallet to restore a backup from such wallets.
Not verifiable: No Open Source Code found
This verdict means that we could not find any source to compile the app from. Internally the company might do everything right but as we can't verify it, there is nothing protecting the user from an exit-scam where the provider releases an app that leaks the keys to the servers.
The app 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 app 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.