the existence and location of files that may contain incriminating information." In another case, a district court judge ordered a Colorado woman to decrypt her laptop so prosecutors can use the files against her in a criminal case: "I conclude that the Fifth Amendment is not implicated by requiring production of the unencrypted contents of the Toshiba Satellite M305 laptop computer," Colorado U.S. District Judge Robert Blackburn ruled on January 23, 2012. In Commonwealth v. Gelfgatt, the court ordered a suspect to decrypt his computer, citing exception to Fifth Amendment can be invoked because "an act of production does not involve testimonial communication where the facts conveyed already are known to the government...". However, in United States v. Doe, the United States Court of Appeals for the Eleventh Circuit ruled on 24 February 2012 that forcing the decryption of one's laptop violates the Fifth Amendment. The Federal Bureau of Investigation may also issue national security letters that require the disclosure of keys for investigative purposes. One company, Lavabit, chose to shut down rather than surrender its master private keys due to the government wanting to spy on Edward Snowden's emails. Since the summer of 2015, cases have been fought between major tech companies such as Apple over the regulation of encryption with government agencies asking for access to private encrypted information for law enforcement purposes. A technical report was written and published by MIT Computer Science and Artificial Intelligence Laboratory, where Ronald Rivest, an inventor of RSA, and Harold Abelson, a computer science professor at MIT with others, explain the technical difficulties, including security issues that arise from the regulation of encryption or by making a key available to a third party for purposes of decrypting any possible encrypted information. The report lists scenarios and raises questions for policy makers. It also asks for more technical details if the request for regulating encryption is to be pursued further. In 2019, the Pennsylvania Supreme Court, in a ruling that only controls for that state's law, held that a suspect in a child pornography case could not be compelled to reveal his password, despite telling the police "We both know what's on there." See also Deniable encryption FBI–Apple encryption dispute Secret sharing Rubber-hose cryptanalysis Crypto Wars References Further reading Bert-Jaap Koops. Bert-Jaap Koops homepage: Crypto Law Survey: Overview per country. Version 26.0. Universiteit van Tilburg. July 2010. Stephen Mason, gen ed, Electronic