The Skeleton in the Hard Drive: Encryption and the Fifth Amendment

Courts are grappling with the question whether forced decryption of computer files violates the Fifth Amendment privilege against self-incrimination. This paper supplies the background necessary for courts to address this question. It explains how full disk encryption works and discusses the nature of encryption technology from a semantic and information theory perspective. It also compares how similar questions have been addressed in other areas of the law that have dealt with computer code as speech: the First Amendment and Copyright law. The paper argues that disclosure of a password or encryption key is not a testimonial act and therefore is not privileged under the Fifth Amendment.