I'm assigning all my MongoDB documents a GUID using uuid.uuid1(). I want a way I can derive an 11 character, unique, case-sensitive YouTube-like ID, such as 

```
1_XmY09uRJ4 

```

from uuid's resulting hex string which looks like

```
ae0a0c98-f1e5-11e1-9t2b-1231381dac60

```

I want to be able to match the shortened ID to the hex and vice-versa, dynamically without having to store another string in the database. Does anyone have some sample code or can point me in the direction of the module or formula that can do this?