FileVault foibles

A little over a month ago I was having some font issues with LaTeX, and I wasn’t sure why. In fact, I never really figured out why. But basically I was getting some ugly bitmap fonts, and I wasn’t going to accept that. So I tried a bunch of things, including trying to re-install tetex. Eventually, I decided to totally re-install fink. In the process, I thought I could maybe just copy the whole /sw directory from my external hard-drive backup. I made one big mistake here though. Instead of copying backup/sw/* to /sw, I copied backup/sw/* to /, meaning that I unintentionally overwrote some important files. So I ended up reinstalling the whole OS. This took some time, but since pretty much everything was backed up, I was not too worried, and it seems like a fresh install is good every now and then anyways.

After, I reinstalled, I decided to try FileVault, which is a neat idea in theory. It encrypts your entire home directory as a sparse disk image, and when you log in, decrypts it on the fly. While you are logged in, it looks like a normal home directory. When you are logged out, it is one large password-protected and encrypted file. So, if you lose your laptop, your data is safe. Even if someone takes the hard-drive out of your computer. Your data is 128-bit AES encrypted, and unless they guess your password, it is very hard to crack.

Great in theory. In practice, after a month of testing it out, I decided to give up. Here were my problems:

  • slow
    While reading was not affected much, writing was severely slowed down. For my dissertation work I have some huge (9000+ rows) Excel files, and every time I went to save, it would take about 10 seconds. I read up some online about it, and found similar complaints from others. I also found suggestions to not store your pictures or music in your home directory. So I ended up moving a bunch of stuff around
  • Office crashing
    Although I generally hate Microsoft Office, I am not yet free from its reins. I noticed that while I had FileVault turned on, if I started to open a document from any Office program, and clicked on the dropdown list of recently used folders, the program would crash. Turned FileVault off, and voila! — problem solved
  • Graphic converter crippled
    Graphic Converter is an excellent Mac program that convert just about any image type into just about any other. It is shareware, but pretty good shareware. Without paying you get almost full functionality except customizing batch processing. I finally ponied up the $30 about a year ago, and it has definitely been worth it. So, batch processing. For batch processing Graphic Converter does not use the native file chooser, but uses its own. It would not recognize my home directory using FileVault. How crappy.

Finally, I decided that I didn’t really have that much sensitive data. I do store my bank statements on my computer, which I do not want to get stolen. So finally I decided to take the same approach that filevault does, but with only a very small subset of my hard drive. I found some great hints on the web to do this Mac OSX hints
It is also possible to use Apple’s Disk Utility, but that is obviously not as fun as the command line. So here are the two commands you need:

create an image

hdiutil create -size thesize -encryption -type SPARSE -fs HFS+ thename

shrink the image

hdiutil compact /some_path/your.sparseimage

There you have it. If you do have a bunch of sensitive data (on a laptop especially), I would nevertheless recommend using FileVault, in spite of the problems. If you recall, the last few major cases of personal data theft has been by stealing hard drives and laptops, not by hacking into computer systems. We need both physical and virtual security. Encrypting your data helps on both fronts.

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