Encrypting data in place with TrueCrypt: how long does it really take?

Discussion in 'privacy technology' started by blainefry, Jun 18, 2014.

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  1. blainefry

    blainefry Registered Member

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    I'm curious if anyone has experience with this.

    Basically I've got a pretty decent amount of data (~1TB) on an unencrypted drive, but it's all backed up. I'm curious if it would be more efficient to just create an encrypted volume and format it, and then just copy the files back to the encrypted volume from the backup...as opposed to encrypting everything in place.

    Has anyone bothered doing an encryption-in-place on a large drive before?
     
  2. Syobon

    Syobon Registered Member

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    with default options, about 24 hours.
     
  3. bobbybackster

    bobbybackster Registered Member

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    It's all gonna depend on your hardware. I've seen TC do clean format at

    ~20MB/s on a Pentium P6200 @ 2.13GHz
    ~121MB/s on a Core i5-3317U @ 1.7 GHz

    That might give you a ballpark. (But also as you can see that's quite a range.) One note though, I also noticed the speed tends to progressively slow as time goes on. Not by a lot, but it can become quite a drop if the format takes a while. I remember a 3TB I did a full (i.e. not "Quick") format on and it started at 117-120MB/s but was running 92.6MB/s by the time it was done. That's around a 23% difference, but of course that happened slowly over the course of the whole format. Took maybe 8 hours total.

    The CPU will also of course determine how quickly the data can be encrypted in-place.

    So when comparing whether it would be faster to encrypt in-place or do a clean format and just copy back over, again, it's a question of hardware. It'll depend on what kind (i.e. speed) of drive you're reading/writing, and what your method of transfer is (e.g. FireWire, USB 2.0, USB 3.0, Thunderbolt, etc.)

    So you're looking at the speed of encryption in-place (which will be mostly determined by CPU) vs. speed of a full format (CPU) + speed of transfer (aka: drive read/write speed + bus speed + CPU for OTFE).

    I actually haven't ever had an opportunity or thought to benchmark it, but that would be an interesting exercise.

    My guess:
    I imagine if your CPU is good enough, encryption in-place may be faster, because you're cutting out the whole transfer step.
    But if your CPU is on the lower end, which means your format time will be slower, you might be able to make up some time through a fast transfer (e.g. USB 3.0).

    Something else to keep in mind is that USB transmission is shared among all attached devices on each controller...meaning if you're transferring from one USB drive to another, your max throughput will be divided between those two devices and any others that are attached to the computer (although to overcome this, some machines will feature multiple controllers.) Also of course you'll need to bear in mind the bottleneck caused by the drive read/write speed. USB 3.0 has a theoretical max speed of 5Gbit/s and USB 3.1 & Thunderbolt have 10Gbit/s...but you won't see anything near that in the real world currently...

    http://www.macworld.com/article/2039427/how-fast-is-usb-3-0-really-.html
     
    Last edited: Jul 12, 2014
  4. DesuMaiden

    DesuMaiden Registered Member

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    That's an unreasonably long amount of time.

    Choose this option.

    Do this

    if it would be more efficient to just create an encrypted volume and format it, and then just copy the files back to the encrypted volume from the backup
     
  5. blainefry

    blainefry Registered Member

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