Secure file storage on Linux: dm-crypt

To use dm-crypt, a few modules must be compiled or built into the kernel. You first must enable the device-mapper module that lets you create new logical block devices from portions of existing devices. The block devices then are "mapped" to devices that for our use are treated like normal drive partitions. Once device-mapper is enabled, you then can enable dm-crypt itself; it goes by the name Crypt Target Support in the kernel configuration menu. dm-crypt is the kernel module that we actually use to handle the encryption/decryption using the crypto API available in the 2.6 version kernels.