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Old 04-13-2007, 07:15 AM   #1
Registered: Dec 2006
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Space in Bytes on a partition

i want to encrypt a whole partition with truecrypt, and i dont want to waste space. Is there a way to find out what the EXACT Space (so in bytes) on a partition is?

Thank you.

der Maxist
Old 04-13-2007, 07:29 AM   #2
Registered: Feb 2007
Location: Israel
Distribution: openSuSE
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Just type "df"
Old 04-13-2007, 12:17 PM   #3
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You don't need to know the size of a partition to encrypt it with True Crypt. You only need to specify a size if you are creating a hidden volume. First let me say that I am using True Crypt v4.2a so if there are changes with the new version I am unaware of them. Here is what you do.

Encrypt the partition using truecrypt -c.

Map the partition using truecrypt.

Make a file system on the virtual device using mkfs.

Mount the virtual device.

Then when you need to remount the device you just map the partition to a True Crypt virtual device and mount the virtual device. You can do this in one step once the partition has a file system.

This is how to do it for /dev/hda1. First encrypt the partition using truecrypt.
truecrypt -c /dev/hda1
Volume type:
 1) Normal
 2) Hidden
Select [1]: 1

 1) FAT
 2) None
Select [1]: 2

Hash algorithm:
 1) RIPEMD-160
 2) SHA-1
 3) Whirlpool
Select [1]: 1

Encryption algorithm:
 1) AES
 2) Blowfish
 3) CAST5
 4) Serpent
 5) Triple DES
 6) Twofish
 7) AES-Twofish
 8) AES-Twofish-Serpent
 9) Serpent-AES
10) Serpent-Twofish-AES
11) Twofish-Serpent
Select [1]: 1

Enter password for new volume '/dev/hda1':
Re-enter password:

Enter keyfile path [none]:

TrueCrypt will now collect random data.

Is your mouse connected directly to computer where TrueCrypt is running? [Y/n]:

Please move the mouse randomly until the required amount of data is captured...
Mouse data captured: 100%

Done: 8578.22 MB  Speed: 15.12 MB/s  Left: 0:00:00
Volume created.
Then map the partition to a virtual True Crypt device.
truecrypt /dev/hda1
Enter password for '/dev/hda1':
Create a file system on the virtual device. Note that you can use truecrypt -l to list True Crypt virtual devices.
truecrypt -l
/dev/mapper/truecrypt1 /dev/hda1
/dev/mapper/truecrypt0 /dev/hda7

mkfs -t ext3 /dev/mapper/truecrypt1
mke2fs 1.39 (29-May-2006)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
1098880 inodes, 2196880 blocks
109844 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2252341248
68 block groups
32768 blocks per group, 32768 fragments per group
16160 inodes per group
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632

Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 26 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.
Now you can mount the virtual device using the mount command.
mount /dev/mapper/truecrypt1 /mnt/hda1
You don't have to worry about dismounting the True Crypt volume when the system shuts down. If you want to dismount and unmap a True Crypt virtual device you can do this.
umount /mnt/hda1
truecrypt -d /dev/mapper/truecrypt1
Now, since the partition has been set up you can mount it any time with one command.
truecrypt /dev/hda1 /mnt/hda1
Enter password for '/dev/hda1':
You can even tell True Crypt about mount options for the partition using the -M parameter of the truecrypt utility.
truecrypt -M noexec,sync /dev/hda1 /mnt/hda1
Enter password for '/dev/hda1':
I don't know if you wanted that much information but your question suggested that you didn't understand how to use True Crypt.

Last edited by stress_junkie; 04-13-2007 at 12:23 PM.
Old 04-14-2007, 12:58 PM   #4
Registered: Dec 2006
Posts: 36

Original Poster
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Thanks alot! This is, what i needed.

der Maxist

PS.: There is a very good tutorial in german (personally, I have got no idea about truecrypt, but this goes a bit more in detail, so I dont need to find out myself :-D)



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