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Software components for data protection, secure storage and transfer

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Also by EldoS: Rethync
The cross-platform framework that simplifies synchronizing data between mobile and desktop applications and servers and cloud storages
#36340
Posted: 03/30/2016 10:40:09
by Steve Jensen (Priority Premium support level)
Joined: 02/16/2016
Posts: 16

Files have been submitted.
#36346
Posted: 03/30/2016 17:23:20
by Steve Jensen (Priority Premium support level)
Joined: 02/16/2016
Posts: 16

Please let me know if you need any other information from me before you can look at this.

Thank you
#36348
Posted: 03/30/2016 17:40:09
by Ken Ivanov (EldoS Corp.)

Thank you for the files Steve - and sorry for not giving you an acknowledgment of receipt. We have actually started looking into the files already. I hope we will be able to tell you something more definite tomorrow.

Ken
#36349
Posted: 03/30/2016 18:36:00
by Steve Jensen (Priority Premium support level)
Joined: 02/16/2016
Posts: 16

Thanks for the update.
#36361
Posted: 03/31/2016 10:15:30
by Ken Ivanov (EldoS Corp.)

Hi Steve,

We've conducted some extensive profiling experiments. As per the outcome of our checks, the primitive that consumes a significant share of CPU time in WinZipEncryption mode is password-to-key conversion routine. This routine is performed once for each protected file, so the more files you compress, the longer takes the compression process. The conversion procedure can hardly be optimised, as it basically consists of a large number of SHA1() operations performed in a row. During the investigation we made some code optimisations here and there, but those will only result in speed increase of up to about 15%.

PKWare's encryption is much quicker than Winzip's as it only performs password-to-key conversion once.

What we can probably do, if you are really looking into faster compressions, is optimise the protection procedure to re-use the same encryption salt value for each file being compressed, thus calling the conversion procedure once per archive. This will reduce the security level of your ZIP files (as all the source files residing in a particular archive will be encrypted with the same AES key), but it will allow to speed up the compression dramatically, effectively making its speed comparable to that of PKWare encryption.

Ken
#36366
Posted: 03/31/2016 15:17:26
by Steve Jensen (Priority Premium support level)
Joined: 02/16/2016
Posts: 16

Thank you for conducting the experiments. Any thoughts on how IPWorks is able to compress the same folder in about 2 seconds? I contacted their support and verified that they are generating a unique salt value for each file as well when using AES-256 encryption. I'm just trying to get my head wrapped around the drastic time differences because that is critical for us. I have a demo program created with their trial that I could upload if it would be helpful? Thank you once again.

Steve
#36367
Posted: 03/31/2016 17:09:27
by Ken Ivanov (EldoS Corp.)

Steve,

Thank you. Yes, that would be quite helpful - we'd really like to have a look into the timing differences. Could you please upload the sample to the same ticket where you uploaded the files yesterday?

Ken
#36368
Posted: 03/31/2016 17:15:17
by Steve Jensen (Priority Premium support level)
Joined: 02/16/2016
Posts: 16

Done. It is a trial so I hope it runs on your machine. I didn't try running it on another computer. Thank you again.
#36369
Posted: 03/31/2016 17:44:19
by Ken Ivanov (EldoS Corp.)

Thank you. We'll have a look and get back to you shortly.
Also by EldoS: BizCrypto
Components for BizTalk® and SQL Server® Integration Services that let you securely store and transfer information in your business automation solutions.

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