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GCN : October 2015
30 GCN OCTOBER 2015 • GCN.COM prietary methods to manage forensic data, he said. In addition, the group became aware that police officers worldwide were duplicating their efforts by examining the same images over and over. To categorize the data, Project Vic originally relied on binary hash sets — MD5 digital signatures generated by algorithms — to identify whether seized evidence matched existing library files and datasets. The hashes were maintained in a database police could check to see which images had already been identified. Early versions of the tool were effective in scoring matches, but they tended to support a focus on offenders. “What we’re not doing is finding new victims within that data,” said James Cole, national program man- ager for victim identification at the Department of Homeland Security. “Instead, we were doing the equiva- lent of shoving that victim in the evidence room.” “The mantra of Project Vic is: ‘That’s not where you should be fo- cusing your efforts,’” Cole said. “ What you should be focusing your efforts on is the stuff that didn’t hit. It’s the stuff that’s new to our system because that’s where new victims will be.” TOOLS OF THE TRADE Project Vic’s leaders are working on ways to give investigators more than binary-level tools to process forensic data. Instead, they want to foster a net- work of collaborators who can contrib- ute open standards-based tools to help analyze new child exploitation cases. Recently, the project adopted an open-data exchange format called ODa- ta, which allows vendors to pass data between different forensic tools more easily “instead of being in proprietary boxes,” said Cole, who calls it “one of the huge tenets of our project.” Using OData, Project Vic also de- veloped a protocol called the Video, Image Classification System that sup- ports querying and exchanging hashes without the need to manipulate files directly. VICS was developed to help police agencies focus on victims and other never-before-seen materials. In December 2014, Microsoft donated its PhotoDNA Cloud Service to Project Vic and offered it as a cloud service to other organizations through the Microsoft Azure marketplace. Pho- toDNA can help identify exact copies of an image or video that might have appeared on various websites. The tool is especially useful to investigators try- ing to identify whether a photo taken by a mobile phone is identical to a copy of the photo generated by social media sites, for example. “When the next person uses those hashes, it’s not only going to pick up on the exact match but it’s going to pick up on visually duplicative matches,” Brown said. AT A GLANCE PROJECT: National Child Victim Identification Program ORGANIZATION: Department of Homeland Security Binary hash sets and an open-data exchange format help investigators match images and analyze new child exploitation cases. 1015gcn_020-038.indd 30 10/5/15 12:46 PM
January and February 2016