As confusing as encrypting a computer file may sound, it actually isn't that complex. The simplest way to think about encrypting a computer file is to imagine making a riddle: taking a sentence and then jumbling up all the letters and words, for example. As the creator of the riddle, you know the answer. You know how to make the encrypted message make sense. But other people will have to figure it out, and they may struggle to do so.
Encryption is the same thing. You take a computer file and make it unreadable by encrypting it. Decrypting a file would be the equivalent of figuring out the riddle.
Now, you may be asking "why are we talking about computer encryption and decryption on a criminal defense blog?" Well funny you should ask, because there happens to be an ongoing criminal case dealing with this exact computer element.
A man accused of running a mortgage fraud scheme has some encrypted files on his computer. Federal law enforcement officials failed to decrypt the files on their own -- so they have compelled the accused man to decrypt the files for them.
Understandably, the man and his defense team took exception to this request and argued that it was a violation of his Fifth Amendment rights to not self-incriminate. A lower court agreed with this interpretation, denying the request of federal officials to have the accused man decrypt his own files. They have appealed, and the case will soon be heard in a superior court.
Source: Courthouse News Service, "Forced Decryption Fought as Self-Incrimination," Jack Bouboushian, Nov. 1, 2013