Jacob Appelbaum is an American independent computer security researcher and hacker. He was employed by the University of Washington, and is a core member of the Tor project, a free software network designed to provide online anonymity. Appelbaum is known for representing Wikileaks at the 2010 HOPE conference. He has subsequently been repeatedly targeted by US law enforcement agencies, who obtained a court order for his Twitter account data, detained him 12 times at the US border after trips abroad, and seized a laptop and several mobile phones.
In 2005, Appelbaum gave two talks at the 22nd Chaos Communication Congress,Personal Experiences: Bringing Technology and New Media to Disaster Areas, and A Discussion About Modern Disk Encryption Systems. The former covered his travels to Iraq—crossing the border by foot, the installing of Internet satellites in Kurdistan, and his visit of New Orleans post-Hurricane Katrina. The latter talk discussed the legal and technical aspects of full disk encryption. At the 2006 23rd Chaos Communication Congress, he gave a talk with Ralf-Philipp Weinmann titled Unlocking FileVault: An Analysis of Apple's Encrypted Disk Storage System. The duo subsequently released the VileFaultfree software program which broke Apple's FileVault security.
He regards Tor as a "part of an ecosystem of software that helps people regain and reclaim their autonomy. It helps to enable people to have agency of all kinds; it helps others to help each other and it helps you to help yourself. It runs, it is open and it is supported by a large community spread across all walks of life." 
Jacob Appelbaum at a talk at 30C3 in Hamburg (2013).
Appelbaum has been detained at airports and had his electronic equipment seized several times. In 2010, the US Department of Justice obtained a court order compelling Twitter to provide data associated with the user accounts of Appelbaum, as well as several other individuals associated with Wikileaks. While the order was originally sealed, Twitter successfully petitioned the court to unseal it, permitting the company to inform its users that their account information had been requested.
Appelbaum is an atheist of Jewish background and identifies himself as bisexual. He also is an anarchist and enjoys photography. He has moved to Berlin, where he has applied for residence authorization, his stated reasons include that he doesn't want to go back to the USA because he doesn't feel safe and that privacy protections are better in Germany than in the US. However, in December 2013, Appelbaum said he suspected the government of breaking into his Berlin apartment.
^Rich, Nathaniel (1 December 2010). "The American Wikileaks Hacker". Rolling Stone. Retrieved 3 July 2014. "An anarchist street kid raised by a heroin- addict father, he dropped out of high school, taught himself the intricacies of code and developed a healthy paranoia along the way."