cryptsetup is used to encypt disk on Linux. I used TrueCrypt before this. After TrueCrypt stopped the project, i started using cryptsetup for my encrypted drive.
To mount an encrypted disk, run
cryptsetup luksOpen /dev/sda3 sda3_crypt
Example
cryptsetup luksOpen /dev/sdb4 enfs1 mount /dev/mapper/enfs1 /mnt/tmp
See mount