The Kazaa peer-to-peer software could be designed to block unauthorized file sharing and warn users of copyright infringement, according to a Melbourne professor who will take the witness stand in the Australian Federal Court on Tuesday afternoon.

The record companies' next witness in the trial, Professor Leon Sterling, Adacel chair of software innovation and engineering, University of Melbourne, has filed two affidavits on his examination of Kazaa Media Desktop (KMD) documents.

In the affidavits, filed in court Tuesday morning, Sterling claimed that whether a system was managed centrally or peer-to-peer was only a design detail, not a technically significant characteristic.

Sharman Networks has previously claimed Kazaa and other peer-to-peer systems have limitations as to how they can be controlled.

However, developers have choices in how they design a system, Sterling said: "In my view, there is no conceptual difference between placing a file in the Kazaa "My Shared Folder" and placing it on a single Web site from the point of view of availability to Internet users," he said in the affidavits.

Accordingly, the system could have been designed to gather data on user identities, he said.

"It is certainly possible, in my view, for KMD to have been designed to collect and report the identity and other information about users, if it does not already."

Sterling also claimed in the affidavits that Kazaa's warnings on potential copyright infringement "are not placed in a way that will make users take notice of, or think about, the copyright issue".

He suggested three other measures: one being an authorization step before a Kazaa user uploads a file to My Shared Folder. Sharman could also protect copyright by filtering Kazaa, Sterling said.

Files with the .mp3 extension could be screened, and band names could be blocked, he said.

"(For example) in my view it would be straightforward not to allow any files with "Powderfinger" in the title metadata."

Lawyers for Sharman Networks are expected to cross-examine Sterling later Tuesday.