Target Disk Mode & Security

You can bypass an account password by enabling "Automatic login" in System Preferences > Accounts > Login Options.

 

Which is a very bad idea, especially that most people have their main account with admin privileges.

Vote NO to Automatic Login!

 

Before you go the route of using open firmware password protection, you might want to consider this:

Well, I thought you might wanted to know.

 

Which is not a problem if you have a firmware password enabled.

 

You might want to read this article: Link

Based on my interpretation, it completely blocks the use of those features.

 

A firmware password is not going to "fully secure the data" on your machine. The data would remain unencrypted.

To encrypt your data, simply enable FileVault for your home folder.

 

Anyone could unhook the hard drive from your Mac and mount it if they wanted to (assuming you had valuable data on it and it got nicked).

File vault I don't know too much about - it caused slowdowns in previous versions of OSX, and I've never used it myself.

 

Maybe there is a totally different to accomplish your goal. How much of your data is that sensitive? Maybe you could put it all in a sparseimage. I don't think there is any way to break into a sparse image without the password. I'm sure someone will correct me if I am wrong.

 

An AES-256 sparse image uses the same encryption that Filevault does, so yes, it's generally just as secure for data inside it. You just have to make sure nothing you consider sensitive is stored outside, e.g. in your library folder (caches, etc). If security is a legitimate issue (HIPAA, legal concerns, etc), Filevault plus the other related security options (secure VM, etc) are the best option.

 

Whatever encryption you use, don't forget to keep your private keys safe.

 

I keep passwords and in a spread sheet and put them inside a sparseimage. That might work for you as well, OP

 

For my bank password, I have a few small letters about the wall of my room, left to right in random places.

Lot of effort, but no one could even see them unless they knew where to look. And there is like 15 of them!

 

Umm ... Keychain might be what you are looking for.

I use FileVault, while I am sure it adds some overhead, my system is still running fine, and I feel better that if it gets lost/stolen, my passwords/quicken/etc. won't be easy reading for anybody.

There is a balance between security and convenience, and you have to find the balance that makes you happy. MacWorld had a whole security article a few months back, they went into details about all this stuff.