Question: How do I check if a partition is encrypted? In particular I would like to know how I check if `/home` and swap is encrypted.

Answer: 
Regarding the standard home encryption provided by Ubuntu, you can 

```
sudo ls -lA /home/username/

```

and if you get something like

```
totale 0
lrwxrwxrwx 1 username username 56 2011-05-08 18:12 Access-Your-Private-Data.desktop -> /usr/share/ecryptfs-utils/ecryptfs-mount-private.desktop
lrwxrwxrwx 1 username username 38 2011-05-08 18:12 .ecryptfs -> /home/.ecryptfs/username/.ecryptfs
lrwxrwxrwx 1 username username 37 2011-05-08 18:12 .Private -> /home/.ecryptfs/username/.Private
lrwxrwxrwx 1 username username 52 2011-05-08 18:12 README.txt -> /usr/share/ecryptfs-utils/ecryptfs-mount-private.txt

```

then the username's home directory is encrypted. This works when username is not logged in, so the partition is not mounted. Otherwise you can look at `mount` output.

About the swap, do

```
sudo blkid | grep swap

```

and should check for an output similar to

```
/dev/mapper/cryptswap1: UUID="95f3d64d-6c46-411f-92f7-867e92991fd0" TYPE="swap" 

```
In addition to the answer provided by enzotib, there's the possibility of full disk encryption as provided by the alternate installer. (Also called LUKS-crypt.)

You can use `sudo dmsetup status` to check if there are any LUKS-encrypted partitions. The output should look something like:

```
ubuntu-home: 0 195305472 linear 
ubuntu-swap_1: 0 8364032 linear 
sda5_crypt: 0 624637944 crypt 
ubuntu-root: 0 48824320 linear

```

The line marked "crypt" shows that sda5 has been encrypted. You can see which filesystems are on that via the lvm tools.

In the case of LUKS encryption, the Disk Utility in Ubuntu will also show the encryption layer and the configuration in a graphical manner.