What is the Purpose of passwd.log and CNG Key Isolation in Windows 11?

CNG key isolation, also known as KeyIso, is a system service in Windows that helps protect your private encryption keys. It's an important feature and totally safe to have running. As for the passwd.log file, it’s located in `C:Windowsdebug` and doesn’t store any actual passwords; it's mainly for logging login-related messages. You can generally ignore it, just leave it as is.

Thanks for the info! But why does it show a last modified date of 12/12? I haven’t changed any passwords, nor have I typed any in incorrectly. I even tried testing it, but the modified date didn't change.

That date could be from when the Windows service was last updated or modified. The log file updates aren't necessarily tied to your password changes, so it's normal for it to show dates that don’t match your activities. If the CNG service is working fine, don’t worry about it too much!