How do I know if 7zip used AES256?

zip aes 7zip
Jai picture Jai · Mar 9, 2011 · Viewed 7.4k times · Source

I originally was using WinZip15 to create .ZIP files with AES256 which we later package into .EXE files using WinZip's self extracting tool (since we can't be sure the people we are giving the archives to will have a zip utility that can handle AES-256 ZIP archives).

I started using 7Zip's command line utility to package the ZIP files using

7za a -y -tzip -ptestabc123 -mem=AES256 C:\helloworld.zip C:\test\

Is there anyway to tell if it actually used AES256 to encrypt the archive? It clearly has a password, but other than that it seems difficult to determine. When I created AES256 archives using WinZip15 "View in explorer" did not work, which I presume is normal. When I create archives using 7za (with the -mem=AES256 switch), windows explorer CAN open the zip archive which I find strange.

Answer

Cheeso picture Cheeso · Mar 23, 2011

I don't know about 7zip, but you can create a self-extracting EXE that uses AES56, using DotNetZip's command line tools.

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