Login  
Search All Forums
Dart Home | PowerTCP Zip Compression for Active | Custom Development Reply | PowerTCP Zip Compression for ActiveX Topics | Forums   
AuthorForum: PowerTCP Zip Compression for ActiveX
Topic: CRC missing in ZIP using AES
wmcclure

From: Redmond, WA USA
Posts: 2
Member Since: 01/24/12
posted January 24, 2012 7:20 PM

The CRC is created for all creation options except if AES encryption is chosen (only get 00000000). When will a new release be out?
Using 1.9.2 now.
Jason Farrar (Admin)

From: USA
Posts: 223
Member Since: 07/24/07

Extra Support Options
Custom Application Development

posted January 30, 2012 4:14 PM

According to the WinZip AES specifications here: http://www.winzip.com/aes_info.htm#CRC

The CRC value is supposed to be 0 when using the AE-2 method of encryption which is what we are using in our PowerTCP Zip Compression for ActiveX product.
wmcclure

From: Redmond, WA USA
Posts: 2
Member Since: 01/24/12
posted January 30, 2012 4:33 PM

If you read section IV. Changes in WinZip 11, it states:
WinZip 11 instead uses the AE-1 file format, which does store the CRC, for most files. This provides an extra integrity check against the possibility of hardware or software errors that occur during the actual process of file compression/encryption or decryption/decompression.
It also states:
Other vendors who support WinZip's AES encryption specification may want to consider making a similar change to their own implementations of the specification, to get the benefit of the extra integrity check that it provides.
WinRar and other utilities provide the CRC. I send these files over the internet and need a way to verify the file has successfully transferred.
Would you please consider adding this option?
Thank you.

Jason Farrar (Admin)

From: USA
Posts: 223
Member Since: 07/24/07

Extra Support Options
Custom Application Development

posted February 1, 2012 8:16 AM

Thank you for pointing that out. I've entered it for review in our bug tracking system as Bug #50. You can contact Jamie Powell, jamie.powell@dart.com for information regarding when this issue may be addressed.
Reply | PowerTCP Zip Compression for ActiveX Topics | Forums   
This site is powered by PowerTCP WebServer Tool PowerTCP WebServer for ActiveX