The resumes of over 27,000 people working in the US intelligence community were revealed on Thursday in a searchable database created by mining LinkedIn.
Transparency Toolkit said the database, called ICWatch, includes the public resumes of people working for intelligence contractors, the military, and intelligence agencies.
The group said the resumes frequently mention secret codewords and surveillance programs.
"These resumes include many details about the names and functions of secret surveillance programs, including previously unknown secret codewords," Transparency Toolkit said.
"We are releasing these resumes in searchable form with the hopes that people can use them to better understand mass surveillance programs and research trends in the intelligence community."
The data was collected from LinkedIn public profiles using search terms like known codewords, intelligence agencies and departments, intelligence contractors, and industry terms, the group said.
To create the database, Transparency Toolkit built search software called LookingGlass to make it easy to browse the data. Both Looking Glass and the ICWatch data have been released on Github.
"Transparency Toolkit uses open data to watch the watchers and hold the powerful to account." the group's website says.
"We build free software to collect and analyze open data from a variety of sources. Then we work with investigative journalists and human rights organizations to turn that into useful, actionable knowledge. Currently, our primary focuses are investigating surveillance and human rights abuses."
The trio behind Transparency Toolkit are listed as: Brennan Novak, co-founder and designer of the open-source encrypted email project Mailpile; Kevin Gallagher, a writer, activist, and researcher of the private intelligence contracting industry; and MC McGrath, founder and director of the project, who is also a Thiel Fellow and former researcher at the MIT Media Lab.