Moxie Marlinspike

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Moxie Marlinspike
Moxie Marlinspike TC.jpg
Marlinspike in 2017
Known for
Scientific career
Computer security,
Software architecture Edit this at Wikidata

Matthew Rosenfeld,[1] known as Moxie Marlinspike,[2] is an American entrepreneur, cryptographer, and computer security researcher. Marlinspike is the creator of Signal, co-founder of the Signal Foundation, and currently serves as the CEO of Signal Messenger LLC. He is also a co-author of the Signal Protocol encryption used by Signal, WhatsApp,[3][4] Facebook Messenger,[5] and Skype.[6]

Marlinspike is a former head of the security team at Twitter[7] and the author of a proposed SSL authentication system replacement called Convergence.[8] He previously maintained a cloud-based WPA cracking service[9] and a targeted anonymity service called GoogleSharing.[10]


Originally from the state of Georgia,[3] at 18, Marlinspike moved to San Francisco in the late 1990s.[11][12] He then worked for several technology companies, including enterprise infrastructure software maker BEA Systems Inc.[3][12] In 2004, Marlinspike bought a derelict sailboat and, along with three friends, refurbished it and sailed around the Bahamas while making a "video zine" about their journey called Hold Fast.[11][3][12]

In 2010, Marlinspike was the chief technology officer and co-founder of Whisper Systems,[13] an enterprise mobile security startup company. In May 2010, Whisper Systems launched TextSecure and RedPhone. These were applications that provided end-to-end encrypted SMS messaging and voice calling, respectively. The company was acquired by the social-media firm Twitter for an undisclosed amount in late 2011.[14] The acquisition was done "primarily so that Mr. Marlinspike could help the then-startup improve its security".[12] During his time as head of cybersecurity at Twitter,[15] the firm made Whisper Systems' apps open source.[16][17]

Marlinspike left Twitter in early 2013 and founded Open Whisper Systems as a collaborative open source project for the continued development of TextSecure and RedPhone.[18][19][20] At the time, Marlinspike and Trevor Perrin started developing the Signal Protocol, an early version of which was first introduced in the TextSecure app in February 2014.[21] In November 2015, Open Whisper Systems unified the TextSecure and RedPhone applications as Signal.[22] Between 2014 and 2016, Marlinspike worked with WhatsApp, Facebook, and Google to integrate the Signal Protocol into their messaging services.[23][24][25]

On February 21, 2018, Marlinspike and WhatsApp co-founder Brian Acton announced the formation of the Signal Foundation.[26][11]


SSL stripping[edit]

In a 2009 paper, Marlinspike introduced the concept of SSL stripping, a man-in-the-middle attack in which a network attacker could prevent a web browser from upgrading to an SSL connection in a subtle way that would likely go unnoticed by a user. He also announced the release of a tool, sslstrip,[27] which would automatically perform these types of man-in-the-middle attacks.[28][29] The HTTP Strict Transport Security (HSTS) specification was subsequently developed to combat these attacks.[citation needed]

SSL implementation attacks[edit]

Marlinspike has discovered a number of different vulnerabilities in popular SSL implementations. Notably, Marlinspike published a 2002 paper[30] on exploiting SSL/TLS implementations that did not correctly verify the X.509 v3 "BasicConstraints" extension in public key certificate chains. This allowed anyone with a valid CA-signed certificate for any domain name to create what appeared to be valid CA-signed certificates for any other domain. The vulnerable SSL/TLS implementations included the Microsoft CryptoAPI, making Internet Explorer and all other Windows software that relied on SSL/TLS connections vulnerable to a man-in-the-middle attack. In 2011, the same vulnerability was discovered to have remained present in the SSL/TLS implementation on Apple Inc.'s iOS.[31][32] Also notably, Marlinspike presented a 2009 paper,[33] in which he introduced the concept of a null-prefix attack on SSL certificates. He revealed that all major SSL implementations failed to properly verify the Common Name value of a certificate, so that they could be tricked into accepting forged certificates by embedding null characters into the CN field.[34][35]

Solutions to the CA problem[edit]

In 2011, Marlinspike presented a talk titled SSL And The Future Of Authenticity[36] at the Black Hat security conference in Las Vegas. He outlined many of the current problems with certificate authorities, and announced the release of a software project called Convergence to replace Certificate Authorities.[37][38] In 2012, Marlinspike and Trevor Perrin submitted an Internet Draft for TACK,[39] which is designed to provide SSL certificate pinning and help solve the CA problem, to the Internet Engineering Task Force.[40]

Cracking MS-CHAPv2[edit]

In 2012, Marlinspike and David Hulton presented research that makes it possible to reduce the security of MS-CHAPv2 handshakes to a single DES encryption. Hulton built hardware capable of cracking the remaining DES encryption in less than 24 hours, and the two made the hardware available for anyone to use as an Internet service.[41]


Marlinspike says that when flying within the United States he is unable to print his own boarding pass, is required to have airline ticketing agents make a phone call in order to issue one, and is subjected to secondary screening at TSA security checkpoints.[42]

While entering the United States via a flight from the Dominican Republic in 2010, Marlinspike was detained by federal agents for nearly five hours, all his electronic devices were confiscated, and at first agents claimed he would only get them back if he provided his passwords so they could decrypt the data. Marlinspike refused to do this, and the devices were eventually returned, though he noted that he could no longer trust them, saying, "They could have modified the hardware or installed new keyboard firmware."[43]

Speaking engagements[edit]

  • DEF CON 17: "More Tricks for Defeating SSL"[44]
  • DEF CON 18 and Black Hat 2010: "Changing Threats to Privacy"[45]
  • DEF CON 19 and Black Hat 2011: "SSL and the Future of Authenticity"[46]
  • DEF CON 20: "Defeating PPTP VPNs and WPA2 with MS-CHAPv2"[47]
  • Webstock '15: "Making private communication simple"[48]
  • 36C3: "The ecosystem is moving"[49]


  • In 2013 and 2014, the Shuttleworth Foundation provided Marlinspike with a total of $289,487.18 in funding for Open Whisper Systems.[50]
  • In 2016, Fortune magazine named Marlinspike among its 40 under 40 for being the founder of Open Whisper Systems and "[encrypting] the communications of more than a billion people worldwide".[51] Wired also named Marlinspike to its "Next List 2016," as one of "25 Geniuses Who Are Creating the Future of Business."[52]
  • In 2017, Moxie Marlinspike along with Trevor Perrin were awarded the Levchin Prize for Real World Cryptography "for the development and wide deployment of the Signal protocol".[53][54]


  1. ^ Smith, Matt (15 May 2013). "Saudi's Mobily denies asking for help to spy on customers". Reuters. Retrieved 21 February 2018.
  2. ^ Rosenblum, Andrew (26 April 2016). "Moxie Marlinspike Makes Encryption for Everyone". Popular Science. Bonnier Corporation. Retrieved 9 July 2016.
  3. ^ a b c d Greenberg, Andy (31 July 2016). "Meet Moxie Marlinspike, the Anarchist Bringing Encryption to All of Us". Wired. Condé Nast. Retrieved 31 July 2016.
  4. ^ Wiener, Anna. "Taking Back Our Privacy". The New Yorker. Retrieved 2020-10-28.
  5. ^ Greenberg, Andy (4 October 2016). "You can finally encrypt Facebook Messenger, so do it". Wired.
  6. ^ Newman, Lily Hay (11 January 2018). "Skype Finally Starts Rolling Out End-to-End Encryption". Wired.
  7. ^ Hern, Alex (17 October 2014). "Twitter's former security head condemns Whisper's privacy flaws". The Guardian. Retrieved 22 January 2015.
  8. ^ Messmer, Ellen (12 October 2011). "The SSL certificate industry can and should be replaced". Network World. IDG. Archived from the original on 1 March 2014. Retrieved 25 September 2016.
  9. ^ "New Cloud-Based Service Steals Wi-fi Passwords". PC World. Retrieved 2013-12-09.
  10. ^ "A Better Way To Hide From Google". Forbes. 2013-11-25. Archived from the original on 12 October 2013. Retrieved 2013-12-09.
  11. ^ a b c Wiener, Anna (19 October 2020). "Taking Back Our Privacy : Moxie Marlinspike, the founder of the end-to-end encrypted messaging service Signal, is "trying to bring normality to the Internet."". The New Yorker. Retrieved 27 October 2020.
  12. ^ a b c d Yadron, Danny (9 July 2015). "Moxie Marlinspike: The Coder Who Encrypted Your Texts". The Wall Street Journal. Archived from the original on 10 July 2015. Retrieved 27 September 2016.
  13. ^ Mills, Elinor (2011-03-15). "CNet: WhisperCore App Encrypts All Data For Android". Retrieved 2013-12-09.
  14. ^ "Twitter Acquires Moxie Marlinspike's Encryption Startup Whisper Systems". Forbes. Retrieved 2013-10-04.
  15. ^ Powers, Shawn M.; Jablonski, Michael (February 2015). The Real Cyber War: The Political Economy of Internet Freedom. University of Illinois Press. p. 198. ISBN 978-0-252-09710-2. JSTOR 10.5406/j.ctt130jtjf.
  16. ^ Chris Aniszczyk (20 December 2011). "The Whispers Are True". The Twitter Developer Blog. Twitter. Archived from the original on 24 October 2014. Retrieved 22 January 2015.
  17. ^ "RedPhone is now Open Source!". Whisper Systems. 18 July 2012. Archived from the original on 31 July 2012. Retrieved 22 January 2015.
  18. ^ Yadron, Danny (10 July 2015). "What Moxie Marlinspike Did at Twitter". Digits. The Wall Street Journal. Archived from the original on 18 March 2016. Retrieved 27 September 2016.
  19. ^ Andy Greenberg (29 July 2014). "Your iPhone Can Finally Make Free, Encrypted Calls". Wired. Retrieved 18 January 2015.
  20. ^ "A New Home". Open Whisper Systems. 21 January 2013. Retrieved 11 July 2015.
  21. ^ Donohue, Brian (24 February 2014). "TextSecure Sheds SMS in Latest Version". Threatpost. Retrieved 14 July 2016.
  22. ^ Greenberg, Andy (2 November 2015). "Signal, the Snowden-Approved Crypto App, Comes to Android". Wired. Condé Nast. Retrieved 24 November 2015.
  23. ^ Metz, Cade (5 April 2016). "Forget Apple vs. the FBI: WhatsApp Just Switched on Encryption for a Billion People". Wired. Condé Nast. Retrieved 2 August 2016.
  24. ^ Greenberg, Andy (8 July 2016). "'Secret Conversations:' End-to-End Encryption Comes to Facebook Messenger". Wired. Condé Nast. Retrieved 24 September 2016.
  25. ^ Greenberg, Andy (18 May 2016). "With Allo and Duo, Google Finally Encrypts Conversations End-to-End". Wired. Condé Nast. Retrieved 24 September 2016.
  26. ^ Marlinspike, Moxie; Acton, Brian (21 February 2018). "Signal Foundation". Retrieved 21 February 2018.
  27. ^ "sslstrip". Retrieved 2013-12-09.
  28. ^ Greenberg, Andy (18 February 2009). "Breaking Your Browser's Padlock". Forbes. Archived from the original on 27 February 2014.
  29. ^ Kelly Jackson Higgins February 24, 2009 (2009-02-24). "SSLStrip Hacking Tool Released". Retrieved 2013-12-09.
  30. ^ "BasicConstraints Vulnerability". Retrieved 2013-12-09.
  31. ^ Apple iOS Bug Worse Than Advertised/
  32. ^ "iPhone data interception tool released". 2011-07-27. Archived from the original on 2013-12-14. Retrieved 2013-12-09.
  33. ^ "More New Tricks For Defeating SSL In Practice". 2011-01-15. Retrieved 2013-12-09.
  34. ^ Zetter, Kim (2009-07-30). "Vulnerabilities Allow Attackers To Impersonate Any Website". Retrieved 2013-12-09.
  35. ^ Goodin, Dan (2009-07-30). "Wildcard certificate spoofs web authentication". Retrieved 2013-12-09.
  36. ^ "SSL And The Future Of Authenticity". 2011-08-18. Retrieved 2013-12-09.
  37. ^ "New SSL Alternative". Archived from the original on 2011-10-01. Retrieved 2013-12-09.
  38. ^ "Future of SSL in doubt?". 2011-08-09. Retrieved 2013-12-09.
  39. ^ "Trust Assertions For Certificate Keys". Retrieved 2013-12-09.
  40. ^ Goodin, Dan (2012-05-23). "SSL fix flags forged certificates". Retrieved 2013-12-09.
  41. ^ "New Tool From Moxie Marlinspike Cracks Some Crypto Passwords". threatpost. 19 August 2012. Archived from the original on 19 August 2012.CS1 maint: bot: original URL status unknown (link)
  42. ^ Mills, Elinor (2010-11-18). "Security researcher: I keep getting detained by feds". CNET. Retrieved 2019-06-19.
  43. ^ Zetter, Kim (2010-11-18). "Another Hacker's Laptop, Cellphones Searched At Border". Retrieved 2019-06-19.
  44. ^ "DEF CON 17 - Moxie Marlinspike - More Tricks for Defeating SSL". YouTube. DEF CON. Retrieved 22 January 2015.
  45. ^ "DEF CON 18 - Moxie Marlinspike - Changing Threats To Privacy: From TIA to Google". YouTube. DEF CON. Retrieved 22 January 2015.
  46. ^ "DEF CON 19 - Moxie Marlinspike - SSL And The Future Of Authenticity". YouTube. DEF CON. Retrieved 22 January 2015.
  47. ^ "DEF CON 20 - Marlinspike Hulton and Ray - Defeating PPTP VPNs and WPA2 Enterprise with MS-CHAPv2". YouTube. DEF CON. Retrieved 22 January 2015.
  48. ^ "Webstock '15: Moxie Marlinspike - Making private communication simple". Vimeo. Webstock. Retrieved 22 April 2015.
  49. ^ "36C3 - The ecosystem is moving". YouTube. 36C3. Retrieved 6 January 2020.
  50. ^ "Moxie Marlinspike". Shuttleworth Foundation. n.d. Archived from the original on 15 November 2016. Retrieved 25 September 2016.
  51. ^ "Moxie Marlinspike - 40 under 40". Fortune. Time Inc. 2016. Retrieved 22 September 2016.
  52. ^ Staff, WIRED (2016-04-26). "25 Geniuses Who Are Creating the Future of Business". Wired. ISSN 1059-1028. Retrieved 2020-03-19.
  53. ^ "The Levchin Prize for Real World Cryptography". RealWorldCrypto.
  54. ^ Levchin, Max (4 January 2017). "2017 Levchin Prize for Real World Cryptography". Yahoo! Finance. Retrieved 7 February 2018.

External links[edit]