[ubuntu-cloud] Wiping an instance snapshot -- possible or necessary?

[Robert Citek]

Is it necessary or even possible to wipe an instance snapshot?

A client of ours created an EC2 instance for some testing work, put
some sensitive data on it, took several snapshots in the course of
doing testing, and now wants to wipe the EBS volume and the snapshots.
 Yes, the "right way" would have been to put the data on an encrypted
volume and then we wouldn't have to worry about wiping.  But since
this was not done (or are snapshots automatically encrypted?), he is
looking into alternatives.

Wiping the EBS volume is relatively straightforward:

- detach the volume from the current instance
- mount the volume in a new instance (e.g. /dev/sdf1)
- shred -n 0 -z /dev/sdf1

But how does one wipe the snapshots?

>From Googling it appears that this may not be possible, or at the
least very non-obvious.  But I'm also wondering if wiping is needed.

Any pointers in the right direction are greatly appreciated.

Regards,
- Robert