This book provides information about common attacks on hard disk encryption and the modes of operation used. Little information is available on this topic, which has lead to a confused and misinformed general public. The Institute of Electrical and Electronic Engineers (IEEE) suggests using Tweaked CodeBook Mode (TCB) with CipherText Stealing (CTS) (short XTS) as the new standard for block cipher modes. Special attention is given to that area. Information is also given about attacks on hard disk encryption. Furthermore, relevant cryptology topics are discussed, namely block ciphers, block cipher modes, password authentication and biometrics. We also take a look at the points that must be considered when choosing a hard disk encryption system as well as how to increase usability and integrity. Finally, the use of passwords and biometric systems for authentication in a way to improve security is outlined.