Computer Ethics, Summer 2017

Corboy 302, Tuesdays and Thursdays
Class 5

Class 5 Readings

Read Baase chapter 2 on privacy

The main course notes are in the Notes Organized by Topic section on the main web page. Reading assignments, comments on the class discussion and occasional special notices are in these week-by-week notes.

Supreme Court will hear Carpenter v United States

Timothy Carpenter was allegedly the mastermind behind a series of armed cellphone-store robberies. But Carpenter himself was never at the scene. The police arrested one suspect who agreed to turn over his phone. The police then used the contact information to develop a list of suspects; they then obtained a subpoena (but not a warrant) for historical nearest-tower records of those phones and these records placed Carpenter in the vicinity of several of the robberies.

The legal question is whether a subpoena is sufficient for these kinds of records, under the Stored Communications Act, or whether a warrant is necessary.


Note that this is not about GPS: many magistrate judges seem to feel that a subpoena is sufficient for future (but not historical?) nearest-tower records, but that GPS records require a warrant.

Reality Winner caught via printer dots

Reality Winner was arrested recently for leaking documents to The Intercept. Winner printed out the documents and sent them in, and The Intercept then scanned and released them.

The Intercept was founded after the Snowden revelations by Glenn Greenwald, Laura Poitras and Jeremy Scahill for the purpose of writing exposés about government misbehavior that is revealed through leaked disclosures.

Winner's problem was that the printer she used printed tiny yellow dots that served to identify the printer and the time of printing. The dots are (barely) visible in the grey area at the top of the image here: Knowing where and when the document was printed, it was easy for the NSA to tie the printing to Winner. (The NSA may have been able to identify her anyway, simply because she printed the document at work, and the list of NSA workers who did that was pretty short.)

Technical dot details are at
General information is at

What Winner should have done was to send the original pdf files. Maybe those would have been harder to sneak out?