better tests and error handling

What if one party sends a bad key event? Should test that it correctly sends a cancel event of invalid_message

I don't think we want to do this. The benefits of keeping Crypto a value type isn't great. For example, it delays saving of the crypto state, which can cause problems in the case of a crash / kill of the process. A solution might be to make Crypto a dependency of the store instead.

mmore tests and error handling

Move state into VerificationProcess

more error handling

In D282#5560, @nannanko wrote:

When I enter a wrong password, then open the input box again, the old password will still be retained. Especially when I click the "show password", the input box will retain this setting. This is obviously inconsistent with the behavior of most similar software and may lead to unexpected occurrences.

Clear password before showing dialog

Open file when cache success

When I enter a wrong password, then open the input box again, the old password will still be retained. Especially when I click the "show password", the input box will retain this setting. This is obviously inconsistent with the behavior of most similar software and may lead to unexpected occurrences.