Digital Whistleblowing in Restricted Environments

The exposure of an organisation’s illegal or unethical practices is often known as whistleblowing. It is currently a highprofile activity as a consequence of whistleblowing websites such as Wikileaks. However, modern digital fingerprinting technologies allow the identification of the human users associated with a particular copy of a leaked digital file. Fear of such discovery may discourage the public from exposing illegal or unethical practices. This paper therefore introduces the novel whistleblowerdefending problem, a unique variant of the existing documentmarking and traitor-tracing problems. It is addressed here by outlining practical steps that real-world whistleblowers can take to improve their safety, using only standard desktop OS features. ZIP compression is found to be useful for indirect file comparison, in cases where direct file comparison or use of checksums is impossible, inconvenient or easily traceable. The methods of this paper are experimentally evaluated and found to be effective.