Abstract
The most common way to implement full-disk encryption (as opposed to encrypted file systems) in the GNU/Linux operating system is using the encrypted loop device, known as CryptoLoop. We demonstrate clear weaknesses in the current CBC-based implementation of CryptoLoop, perhaps the most surprising being a very simple attack which allows specially watermarked files to be identified on an encrypted hard disk without knowledge of the secret encryption key.
We take a look into the practical problems of securely booting, authenticating, and keying full-disk encryption. We propose simple improvements to the current CryptoLoop implementation based on the notions of tweakable encryption algorithms and enciphering modes. We also discuss sector-level authentication codes.
The new methods have been implemented as a set of patches to the Linux Kernel series 2.6 and the relevant system tools.
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Saarinen, MJ.O. (2005). Encrypted Watermarks and Linux Laptop Security. In: Lim, C.H., Yung, M. (eds) Information Security Applications. WISA 2004. Lecture Notes in Computer Science, vol 3325. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-31815-6_3
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DOI: https://doi.org/10.1007/978-3-540-31815-6_3
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