As others have noted, it is partially because Crashplan is a Java based app. Partially, it is also because Crashplan runs as System, not as the user. That way, I can have Crashplan backup my wife's user account and my user account.

Furthermore, you can use the encryption key + a custom password, or your own encryption key with a passphrase. In this case, it is encyrpted locally and the key is not sent to Crashplan[1].

[1] http://support.crashplan.com/doku.php/recipe/change_security...

I'm assuming this because their desktop client is a java app and it it's been made to run on linux, mac and Windows. Is there such a thing as a keychain on Windows? I've only used it on linux and mac.

I see what you mean. I have up voted your original comment.

Right, which is a largely meaningless distinction: if the process runs as you, any successful attacker can simply read it out of the CrashPlan process in memory.

Again, if you're not typing the password in every time, a local compromise is almost certainly game-over. Apple's keychain helps reduce the damage if the data's not actively used but for something like CrashPlan which is always running the attacker is probably going to be lucky.

Then no, it does not worry me. Obscuring password entry in an application that I almost never run is not a problem. Plus, if I do actually run the app and want to enter the password, I don't do it with a bunch of people peering over my shoulder.