If malware has compromised your device, there is nothing you can meaningfully do to improve the security that is already offered by a password manager. This sce

If malware has compromised your device, there is nothing you can meaningfully do to improve the security that is already offered by a password manager. This scenario is right up there with physical access to the machine - you're already screwed. To comment on this specific example - if you add the same set of characters to every item in a password manager, an attacker can deduce that it's a common obfuscation method.