Possible Duplicate:
How to encrypt ubuntu filesystems only?
Friends, I have Windows 7 ultimate 64bit and Ubuntu 11.10 64bit version. My laptop comes with 500GB HDD and did 8 partitions. in that 5 are NTFS and 3 partitions for ubuntu as follow swap home and /. i want encrypt my alll my linux partitions only.not on my windows is it possible. plz explain me step by step.. thanks a lot...
It is not that easy to do that and you should know exactly what you are doing. Writing a stepwise instruction set here is nearly impossible, but there are good official How-To's:
https://help.ubuntu.com/community/EncryptedFilesystemHowto#So_How_Do_I_Encrypt_My_Home_Directory.3F
Relatively easy will be to encrypt your home folder, if you get a partition freed, then you can move your data to the new "encrypted partition" and after that mount this new partition using the fstab file. Encrypting the wohle ubuntu installation requires much experience and should be done with care.