How difficult is it to encrypt the hard drive on your personal computer?

For more than a year, the government has not been able to see what is in drive Z, which is protected by an encryption program that is sold under the name Pretty Good Privacy, according to court records. Pretty Good Privacy, which is more commonly known as PGP, is an industry standard of hard-drive encryption and email encryption, according to experts. Encryption is a complex, password-protected method of keeping information, hard drives, devices — almost anything — private. "If you hand me someone's normal laptop, it is relatively easy to bypass passwords. All you have to do is rip out the hard drive out and put it into a different computer," said Charles Miller, a principal security analyst at Independent Security Evaluators and former employee of the National Security Agency. "PGP is full-disk encryption, which means the entire disk is encrypted and the only way in is to know the password. The program makes a key and that key is a password, without it you can't get into to the drive." Jonathon Giffin, an assistant computer science professor at Georgia Tech, said without the password there was only one way to get into the computer: with "brute force."
"They start trying all possible passwords, hoping that they have passwords that you use," Giffin said. "The expected time it would take is years, decades, unless you have extremely powerful computers."
Even the FBI doesn't have that kind of computing power, according to Giffin.
"The FBI probably does not. The NSA probably does," he speculated. "That's really one of the NSA's jobs — to develop cryptosystems for our military as well as to crack the cryptosystems of other governments."


Links: http://i.abcnews.com/Technology/LegalCenter/story?id=4264587&page=1
http://www.pgp.com/