Zipped Files, Encrypted

For years, computer files compressed with the ubiquitous "Zip" standard have been readable by rival programs, regardless of the software used to make the original archive.

Now there are signs it will no longer be so convenient.

Two leading makers of compression software, PKWare and WinZip, have recently upgraded their products to incorporate encryption for increased security. Problem is, they're not using the same technology.

That means a file encrypted and compressed by PKZip might not be readable by someone who uses a different program, such as WinZip. Compression and archiving is commonly used to combine files and shrink them so they're easier to store or transfer.

Still, it's not expected to be a major problem - at least to those who don't encrypt their compressed computer data. Users who want the extra security will have to ensure any recipients can unscramble the zipped files.

Edwin Siebesma, president of WinZip Computing, said the problem arose when PKWare started offering its new software without publishing the details for the entire Zip community.

"It's very unfortunate," he said.

Steve Crawford, chief marketing officer at PKWare, said the company does not release all the details until its software has been thoroughly tested across all supported operating systems.

PKWare plans to post the details once testing and development are complete.

The Zip format has been a reliable standard since 1989, when the late programmer Phil Katz released his code into the public domain so all programs would interoperate.

By Matthew Fordahl