Paul Calder Le Roux (born 24 December 1972) is a former programmer, former criminal cartel boss, and informant to the US Drug Enforcement Administration (DEA).
In 1999, he created E4M, a free and open-source disk encryption software program for Microsoft Windows, and is sometimes credited for open-source TrueCrypt, which is based on E4M's code, though he denies involvement with TrueCrypt.
Le Roux was arrested on 26 September 2012 for conspiracy to import narcotics into the United States, and agreed to cooperate with authorities in exchange for a lesser sentence and immunity to any crimes he might admit to later. He subsequently admitted to arranging or participating in seven murders, carried out as part of an extensive illegal business empire.