Bram Cohen

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Bram Cohen
Cohen in 2015
Born (1975-10-12) October 12, 1975 (age 48)
Alma materUniversity at Buffalo
Occupation(s)Chief executive officer, Chia Network
Known forBitTorrent protocol
SpouseJenna Cohen
RelativesRoss Cohen (brother)
Time 100

Bram Cohen is an American computer programmer, best known as the author of the peer-to-peer (P2P) BitTorrent protocol in 2001, as well as the first file sharing program to use the protocol, also known as BitTorrent. He is also the co-founder of CodeCon and organizer of the San Francisco Bay Area P2P-hackers meeting, was the co-author of Codeville and creator of the Chia cryptocurrency which implements the proof of space-time consensus algorithm.

Early life and career[edit]

Cohen grew up in the Upper West Side of Manhattan, New York City, as the son of a teacher and computer scientist. He claims he learned the BASIC programming language at the age of 5 on his family's Timex Sinclair computer. Cohen passed the American Invitational Mathematics Examination to qualify for the United States of America Mathematical Olympiad while he attended Stuyvesant High School in New York City. He graduated from Stuyvesant in 1993[1] and attended SUNY Buffalo. He later dropped out of college to work for several dot com companies throughout the mid to late 1990s, the last being MojoNation, an ambitious but ill-fated project he worked on with Jim McCoy.

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.

Cohen says that he has Asperger syndrome[2] based on a self diagnosis.[3]


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.

In late 2003, Cohen had a short career at Valve, working on Steam, their digital distribution system introduced for Half-Life 2. [citation needed]

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.[4] Cohen left BitTorrent, Inc. in a day to day capacity to co-found Chia Network in the fall of 2017.[5]

BitTorrent and the MPAA[edit]

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.[6]

Chia Network[edit]

Chia Network is a company founded by Cohen in 2017[7] that has implemented a proof of space-time cryptocurrency called Chia. Chia is intended to avoid the waste of energy involved in proof-of-work-based cryptocurrencies such as Bitcoin,[8] and the vulnerability to state actors of proof-of-stake systems.

Chia Network has raised seed money from investors including Andreessen Horowitz.[8] 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,[9] as well as radically reducing the lifetime of drives.[10]

Personal life[edit]

As of 2008, Cohen lived in the San Francisco Bay Area of the United States, with his wife Jenna and their three children.[11]

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]


Cohen has received a number of awards for his work on the BitTorrent protocol. These awards include:


  1. ^ Cohen, Bram. "Resume". Archived from the original on July 8, 2011. Retrieved April 3, 2014.
  2. ^ a b c Thompson, Clive (January 2005). "The BitTorrent Effect". Wired. Archived from the original on March 26, 2006. Retrieved March 18, 2006.
  3. ^ Roth, Daniel (November 14, 2005). "Torrential Reign". Fortune. pp. 91–96. Archived from the original on April 8, 2006. Retrieved November 6, 2006.
  4. ^ BitTorrent Inc. (2011). "BitTorrent Live JukeBox". BitTorrent Live Beta. BitTorrent Inc. Archived from the original on October 25, 2013. Retrieved September 7, 2012.
  5. ^ Constine, Josh (November 8, 2017). "BitTorrent inventor announces eco-friendly bitcoin competitor Chia". TechCrunch. Archived from the original on January 26, 2018. Retrieved January 18, 2018.
  6. ^ Gentile, Gary (November 23, 2005). "Hollywood Hopes BitTorrent Deal Will Reduce Illegal Movie Downloads". Information Week.[permanent dead link]
  7. ^ Constine, Josh (November 8, 2017). "BitTorrent inventor announces eco-friendly bitcoin competitor". TechCrunch. Archived from the original on January 26, 2018. Retrieved November 12, 2021.
  8. ^ a b "Energy-saving Bitcoin rival Chia raises from A16Z, plans mini-IPO". TechCrunch. March 28, 2018. Archived from the original on February 13, 2021. Retrieved February 15, 2021.
  9. ^ Humphries, Matthew (April 19, 2021). "Chia Cryptocurrency Expected to Cause Hard Drive and SSD Shortages". PC Magazine. Archived from the original on May 10, 2021. Retrieved May 10, 2021.
  10. ^ Lilly, Paul (May 11, 2021). "Chia mining can wreck a 512GB SSD in as little as 6 weeks". PC Gamer. Archived from the original on May 17, 2021. Retrieved May 19, 2021.
  11. ^ Susan Berfield (October 15, 2008). "BitTorrent's Bram Cohen Isn't Limited by Asperger's". Bloomberg Businessweek. Bloomberg L.P. Archived from the original on May 22, 2017. Retrieved March 22, 2016.
  12. ^ "Bram Cohen's Journal". Retrieved September 24, 2022.
  13. ^ 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.
  14. ^ Jason McIntosh (June 21, 2009). "Bram Cohen's puzzle shop". The Gameshelf. Archived from the original on January 11, 2012. Retrieved September 7, 2012.
  15. ^ Oskar van Deventer (October 9, 2010). "Gear Shift". YouTube. Archived from the original on July 4, 2016. Retrieved May 14, 2013.
  16. ^ Oskar van Deventer (August 25, 2012). "Bram's Fortress". YouTube. Archived from the original on October 13, 2016. Retrieved May 14, 2013.
  17. ^ Bram Cohen (August 25, 2012). "Bram Cohen Puzzles". Shapeways. Archived from the original on November 16, 2013. Retrieved May 14, 2013.
  18. ^ "Wired 12.04: The 2004 Wired Rave Awards". Wired. January 4, 2009. Archived from the original on May 27, 2012. Retrieved November 11, 2011.
  19. ^ "2005 Young Innovators Under 35: Bram Cohen, 29". MIT Technology Review. 2005. Archived from the original on January 28, 2012. Retrieved August 14, 2011.
  20. ^ "Special Issue: The Time 100". Time. April 10, 2005. Archived from the original on November 5, 2012. Retrieved July 14, 2010.
  21. ^ "Usenix Stug Award". USENIX. Archived from the original on January 11, 2012. Retrieved November 11, 2011.
  22. ^ "The Big Report – The Internet Evolution 100". Internet Evolution. Archived from the original on August 31, 2013. Retrieved November 11, 2011.

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