Learn in the textbookMalware Distribution Routes and Extortion Tactics
DefinitionDouble extortion (ダブルエクストーション) is the English name, written in katakana, for the tactic known in Japanese as 二重脅迫 (double extortion); both refer to exactly the same thing.
ExplanationIn Japanese the term is just the English phrase written in katakana, and it likewise combines encryption with the threat of publication. Security news and reports use both the Japanese name and the English-derived one.
Memory hookExtortion means obtaining money through threats; add double and you get two threats at once.