"Guccifer 2.0" is a person or persona stating they were the hacker(s) that hacked into the Democratic National Committee (DNC) computer network and then leaked its documents to the media, the website , and a conference event. Some of the documents they say they released appear to be forgeries cobbled together from public information and previous hacks, which they then salted with disinformation.
On June 21, 2016, in an interview with Vice "Guccifer 2.0" stated that he is Romanian. On June 30, 2016 and January 12, 2017, "Guccifer 2.0" stated that he is not Russian. However, despite stating that he was unable to read or understand Russian, metadata of emails sent from Guccifer 2.0 to The Hill showed that a predominantly-Russian-language VPN was used. When pressed to use the Romanian language in an interview with Motherboard via online chat, "he used such clunky grammar and terminology that experts believed he was using an online translator."
Some Cybersecurity experts have concluded that "Guccifer 2.0" is likely a creation of the Russian state-sponsored hacking groups thought to have executed the attack, invented to cover up Russian responsibility. The cybersecurity firm CrowdStrike, which was hired by the DNC to analyze the data breach, "posits that Guccifer 2.0 could be 'part of a Russian Intelligence disinformation campaign'," i.e., a creation to deflect blame for the theft. Russia has made use of the invention of "a lone hacker or an hacktivist to deflect blame" in the past, deploying this strategy in previous cyberattacks on the German government and the French network TV5Monde. Thomas Rid of King's College London, a cybersecurity expert, states that it is "'more likely than not' that the whole operation, including the Guccifer 2.0 part, was orchestrated by Russian spies." The hackers responsible for the DNC email leak (a group called Fancy Bear by CrowdStrike) seem to have not been working on the DNC's servers on April 15 which in Russia is a holiday in honor of the Russian military's electronic warfare services.