1

I'm using 7-zip.

I want to compare a huge backup Zip file (200GB) to the unzipped files. (I'm guessing the files are the same, but want to make sure without unzipping 200 GB)

I've tried using Beyond Compare 3 but it claims the .zip files isn't valid. (It is b/c I can open it in 7-zip.

Will CRC(file.zip) = CRC (unzipped (file.zip))? I can calculate a CRC has on the .zip, but don't know if a CRC of a .zip does the CRC on the contents or the .zip itself. I my very simple test, these CRC values were not equal.

Clay Nichols
  • 5,316

1 Answers1

3

It's definitely the CRC32 of the file, not the archived data:

CRC

And that's how your archive manager determines if your files are corrupted. So, if testing the archive suggested a corrupted file (or set of files) then it means the hash of the file after extraction, doesn't correspond to the stored hash value for the file before archiving.

Community
  • 1
NetwOrchestration
  • 3,285