Yes, you are right on that. If the server is compromised a malicious user may change the client-side code to add a backdoor and steal your private key when you

Yes, you are right on that. If the server is compromised a malicious user may change the client-side code to add a backdoor and steal your private key when you unlock it. He'll be able to steal only the keys that are unlocked while the backdoor stays undetected (not all the data). The ideal way to resolve that would be to change the service to an API and offer binaries with a correct signature so the user can check and make sure that they get the correct thing. Actually I tried writing the client binaries using electron (https://github.com/spapas/etsd/tree/master/client https://github.com/spapas/etsd/tree/master/client) but didn't have the time for that :( You are rigth though, I've added a Risks section to warn for that thingie https://github.com/spapas/etsd/blob/master/README.md#risks https://github.com/spapas/etsd/blob/master/README.md#risks