MojoNation allowed people to break up confidential files into encrypted chunks and distribute those pieces on computers also running the software. If someone wanted to download a copy of this encrypted file, they would have to download it simultaneously from many computers. This concept, Cohen thought, was perfect for a file sharing program, since programs like KaZaA take a long time to download a large file because the file is (usually) coming from one source (or "peer"). Cohen designed BitTorrent to be able to download files from many sources, thus
speeding up the download time, especially for users with faster download than upload speeds. Thus, the more popular a file is, the faster a user will be able to download it, since many people will be downloading it at the same time, and these people will also be uploading the data to other users.
BitTorrent
In April 2001, Cohen quit MojoNation and began work on BitTorrent. Cohen unveiled his ideas at the first CodeCon conference, which he and his roommate Len Sassaman created as a showcase event for novel technology projects after becoming disillusioned with the state of technology conferences.
Cohen wrote the first BitTorrent client implementation in Python, and many other programs have since implemented the protocol.
In the summer of 2002, Cohen collected free pornography to lure beta testers to use the program.[2] BitTorrent gained its fame for its ability to quickly share large music and movie files online. Cohen has claimed he has never violated copyright law using his software.[2] Regardless, he is outspoken in his belief that the current media business was doomed to being outmoded despite the RIAA and MPAA's legal or technical tactics, such as digital rights management. In May 2005, Cohen released a trackerless beta version of BitTorrent.
By 2004, he had left Valve and formed BitTorrent, Inc. with his brother Ross Cohen and business partner Ashwin Navin. In 2012 he announced a beta-version of BitTorrent Live for TV broadcasting through the Internet.[3] Cohen left BitTorrent, Inc. in a day to day capacity to co-found Chia Network in the fall of 2017.[4]
BitTorrent and the MPAA
By mid-2005, BitTorrent, Inc. was funded by venture capitalist David Chao from Doll Capital Management, and in late 2005 Cohen and Navin made a deal with the MPAA to remove links to illegal content on the official BitTorrent website. The deal was with the seven largest studios in America. The agreement means the site will comply with procedures outlined in the Digital Millennium Copyright Act.[5]
Chia Network has raised seed money from investors including Andreessen Horowitz.[7] The use of storage media (hard disk and solid-state drives) as the cryptocurrency's mining medium has raised concerns over potential price surges and shortage of high-capacity storage devices,[8] as well as radically reducing the lifetime of drives.[9]
Personal life
As of 2008, Cohen lived in the San Francisco Bay Area of the United States, with his wife Jenna and their three children.[10]
Cohen's hobbies include original origami and juggling up to five balls, but his main interest is in recreational mathematics. Cohen maintains a blog[12] where he frequently discusses trust metrics with software developer Raph Levien, as well as money systems, games of skill, and other math-related topics. He is also an assembly puzzle enthusiast.[13][14] He has designed several puzzles including some in conjunction with Oskar van Deventer including several gear-based puzzles such as Gear Shift[15] and a multiple Rubik's Cube variant called Bram's Fortress.[16] Some of Cohen's puzzle designs are available for 3-D printing via Shapeways.[17]
Awards
Cohen has received a number of awards for his work on the BitTorrent protocol. These awards include:
^BitTorrent Inc. (2011). "BitTorrent Live JukeBox". BitTorrent Live Beta. BitTorrent Inc. Archived from the original on October 25, 2013. Retrieved September 7, 2012.
^Bram Cohen (May 7, 2012). "TCP Sucks". Bram Cohen's Blog. Bram Cohen. Archived from the original on December 16, 2015. Retrieved September 7, 2012.
^Jason McIntosh (June 21, 2009). "Bram Cohen's puzzle shop". The Gameshelf. Archived from the original on January 11, 2012. Retrieved September 7, 2012.
^Oskar van Deventer (October 9, 2010). "Gear Shift". YouTube. Archived from the original on July 4, 2016. Retrieved May 14, 2013.
^Oskar van Deventer (August 25, 2012). "Bram's Fortress". YouTube. Archived from the original on October 13, 2016. Retrieved May 14, 2013.
^Bram Cohen (August 25, 2012). "Bram Cohen Puzzles". Shapeways. Archived from the original on November 16, 2013. Retrieved May 14, 2013.