In many encryption schemes in [Charm](http://charm-crypto.com/) the random group message is used instead of a text-message:

```
msg = group.random(GT)

```

For example, in CP-ABE scheme, random message is used:

```
cpabe = CPabe_BSW07(group)
msg = group.random(GT)  
attributes = ['ONE', 'TWO', 'THREE']

```

See link for scheme details: <http://jhuisi.github.io/charm/charm/schemes/abenc/abenc_bsw07.html>

Can anyone clarify for me whether I can use my own text-message instead of random ID here. I tried with a encoded byte-array but no luck. What is `group.random(GT)`? Can I use a custom message?