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Encrypted Zip Extremely Slow

Also by EldoS: CallbackProcess
A component to control process creation and termination in Windows and .NET applications.
#19672
Posted: 04/05/2012 11:58:38
by Steven Koegler (Standard support level)
Joined: 04/05/2012
Posts: 6

My company bought a license for the SecureBlackbox.Zip library. On our device encrypting/decrypting zip files using WinZipAES128 is about 35 times slower than no encryption.

Is there an auto slow down built in to our license similar to the evaluation license or is encryption/decryption just that slow?
#19673
Posted: 04/05/2012 12:02:08
by Steven Koegler (Standard support level)
Joined: 04/05/2012
Posts: 6

Should add we are using the .Net compact framework.
#19674
Posted: 04/05/2012 12:04:26
by Vsevolod Ievgiienko (EldoS Corp.)

Thank you for contacting us.

First of all you should check if SBUtils.Unit.SetLicenseKey is called only once with a correct license key but not with an evaluation one.
#19675
Posted: 04/05/2012 12:13:16
by Eugene Mayevski (EldoS Corp.)

Do I understand right that it's AES encryption (not compression) that is slow?

AES was optimized for desktop where it performs at the same speed (or even faster) as RijndaelManaged class (.NET AES implementation). On devices, where CLR is different, it's possible that CLR does something not in optimal way.


Sincerely yours
Eugene Mayevski
#19676
Posted: 04/05/2012 12:17:45
by Steven Koegler (Standard support level)
Joined: 04/05/2012
Posts: 6

Yes I am using the correct license key and it is called once at startup. I'm assuming that since we only bought a license for the zip portion of the library that there are some restrictions placed on it since the main SecureBlackBox.dll must still be referenced.
#19677
Posted: 04/05/2012 12:35:13
by Eugene Mayevski (EldoS Corp.)

No, there are no artificial restrictions present. I assume the problem is with the CLR. We will check it of course.


Sincerely yours
Eugene Mayevski
#19678
Posted: 04/05/2012 12:35:34
by Steven Koegler (Standard support level)
Joined: 04/05/2012
Posts: 6

Quote
Do I understand right that it's AES encryption (not compression) that is slow?


Yes the encryp\decrypt is slow. I am going to try encrypting/decrypting normal zip files with the RijndaelManaged class that comes with compact framework and see how it compares time wise. I just wanted to be sure I'm not running into an automatic slow down due to restrictions on our license key. Much like how zipping/unzipping is extremely slow when using the evaluation key.
#19679
Posted: 04/05/2012 14:21:02
by Steven Koegler (Standard support level)
Joined: 04/05/2012
Posts: 6

Just to give you an idea of how drastic the difference is, I zipped 126 files then encrypted them using RijndaelManaged and it took about 30 seconds. Using the WinZipAes128 option the same 126 files took about 13 minutes.
#19680
Posted: 04/05/2012 14:29:49
by Steven Koegler (Standard support level)
Joined: 04/05/2012
Posts: 6

Just tried using PKWare Strong Encryption using Aes and it is fine speed wise. So it looks like it is only the WinZipAes that has the problem.
#19684
Posted: 04/06/2012 05:33:03
by Mykola Olshevsky (Basic support level)
Joined: 07/07/2005
Posts: 450

Hi. What if compress large file - the time difference is the same? The lag can be in key derivation code.
Also, I assume that you are using the latest build of SBB?
Also by EldoS: CallbackProcess
A component to control process creation and termination in Windows and .NET applications.

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