I would double check your values you think you will gain by compression.
Most encryption increases entropy (randomness) into the data, making compression less effective.
I suggest try a few and see what it takes to encrypt and compress, and see how much you gain in disk space for the time it takes to compress. Ex. if it is 10% less of original, but it takes 12 hours, does it worth it?
On a different point -
I highly suggest you take the previous suggestion of take a live, decrypted image, through network or otherwise.
if you do not have a "root" or "administrative" key to decrypt any and all of the SafeBoot drive, your implementation is seriously wrong.
This is what will happen -
You will make a backup of the encrypted image.
You may compress it.
You will store it.
The IT staff will change.
The user will leave.
The original machine will be re-provisioned.
The software vendor will change the encryption product.
Five years down the road you will be looking to read the data because the courts are demanding it.
You will have no way of decrypting because you lost the password, or no longer have the software to do it.
I have seen this repeatedly in large firms.
↧