tcplay is a free (BSD-licensed), pretty much fully featured (including multiple keyfiles, cipher cascades, etc.) and stable TrueCrypt implementation.
Source: github project home
tcplay-git from the AUR.
Encrypting a file as a virtual volume
# losetup -f
to find the first unused loopback device; in this example,
Create a new volume
test.tc, 20M in size for instance, in the working
# dd if=/dev/zero of=test.tc bs=1 count=0 seek=20M # losetup /dev/loop0 test.tc # tcplay -c -d /dev/loop0 -a whirlpool -b AES-256-XTS
Enter a secure password for the volume, and confirm the query to overwrite
test.tc with the new volume. tcplay will then write random data into the
volume. Map the volume and create a filesystem on it in order to mount
# tcplay -m test.tc -d /dev/loop0 # mkfs.ext4 /dev/mapper/test.tc # mount /dev/mapper/test.tc /mnt/truecrypt/
To unset the container,
# umount /mnt/truecrypt # dmsetup remove test.tc # losetup -d /dev/loop0