Encrypted DMG images standard vrs sparse

Apple MACOSX has the means for generating a encrypted  DMG images.  But did you know you have 2 types? Yes the dmg image has the standard and sparse modes.

The difference between the two;  " sparse mode does not pre-built or consume disk space" . As it's used , the disk file space would be consumed.

1st let's used the apple disk-utility to build these to images types for comparison.

( building a std dmg image w/AES128 )

( building a sparse dmg image w/AES128 )

Okay now let's compare the  diskimage final sizes for the regular and sparse 100MB.

 and;

So the advantages with sparse, we still have an encrypted volume but the size is not pre-allocated. Great if you need to encrypted data and then send it to another user.

Opt out of saving the passphrases to your key-chain. If anybody compromised your machine, than will be able to automatically  mount your encrypted volume if the pass phrase is attached to your key-chain.  Password management is great and convenient but weakens security imho.

 As the diskimage is used ( dmg sparse image ) the diskspace will be consumed. Disk space will continuous be consumes as you fill  the volume out & up to the defined sizes that you set during the disk-utility operations.

Ken Felix
NSE ( network security expert) and Route/Switching Engineer
kfelix  -----a----t---- socpuppets ---dot---com
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