Research: Bruce Schneier — Backdoors, Dual_EC and the Public-Private Surveillance Partnership
The cryptographer's case against encryption backdoors in his own words: the 2007 Dual_EC_DRBG warning that Juniper later proved, why an access door for the good guys is a door for everyone, the surveillance partnership between governments and the companies that hold our data, his testimony, and the Crown Sterling episode as the record actually has it.
Contents
Companion pages: NSA and Snowden and the encryption trade-off dispatch.
Bruce Schneier is a security technologist and cryptographer, “a security guru” in The Economist’s phrase, who describes himself as “a public-interest technologist, working at the intersection of security, technology, and people.” He is a fellow at Harvard’s Berkman Klein Center and at the University of Toronto’s Munk School, a lecturer in public policy at the Harvard Kennedy School, a board member of the Electronic Frontier Foundation and Access Now, and chief of security architecture at Inrupt. He designed the Blowfish and Twofish ciphers, has written Crypto-Gram since 1998 and his blog since 2004, and has testified before Congress (Schneier, About). His books include Applied Cryptography (1994), Data and Goliath (2015), A Hacker’s Mind (2023) and, with Nathan E. Sanders, Rewiring Democracy (MIT Press, October 2025), on “how to harness the technology to distribute rather than concentrate power” (book page).
Everything below is his own on-record position, quoted from the essay or testimony where he said it.
1. Dual_EC_DRBG: the warning in 2007
At the CRYPTO 2007 rump session, Dan Shumow and Niels Ferguson showed that the NSA-promoted random-number generator Dual_EC_DRBG could contain a backdoor. Schneier wrote it up for Wired on November 15, 2007: “If someone were to solve just one instance of the algorithm’s elliptic-curve problem, he would effectively have the keys to the kingdom.” His advice: “My recommendation, if you’re in need of a random-number generator, is not to use Dual_EC_DRBG under any circumstances,” and “If you have to use something in SP 800-90, use CTR_DRBG or Hash_DRBG” (Wired, via Schneier; blog, Nov 2007).
2. Juniper: the warning proved
In December 2015 Juniper disclosed unauthorized code in its ScreenOS firewalls; the VPN decryption weakness ran through Dual_EC_DRBG. Schneier’s posts collected the technical analyses, including Matthew Green’s (Dec 21 2015; Apr 2016; Sep 2021).
3. No door for the good guys only
The principle he is best known for in the encryption debate, in his words: “I can’t build an access technology that only works with proper legal authorization, or only for people with a particular citizenship or the proper morality. The technology just doesn’t work that way.” And: “If a backdoor exists, then anyone can exploit it. All it takes is knowledge of the backdoor and the capability to exploit it” (Schneier, Feb 25 2016). In 2014 he listed the precedents: the 2004-05 compromise of Vodafone Greece’s lawful-intercept system, and the Chinese hackers who subverted Google’s intercept system for government requests (Crypto-Gram, Oct 15 2014). The same case for policymakers: The Value of Encryption (April 2016).
4. The public-private surveillance partnership
His thesis is that government and corporate surveillance are one system. “In some cases, the NSA asks for this data nicely. In other cases, it makes use of subtle threats or overt pressure. If that doesn’t work, it uses tools like national security letters.” “The result is a corporate-government surveillance partnership, one that allows both the government and corporations to get away with things they couldn’t otherwise.” “Each group has learned how to use the other’s laws to bypass their own restrictions” (Bloomberg, Aug 5 2013, via Schneier). Data and Goliath develops it: the two are intertwined and support each other, and data the government could not lawfully collect it can buy (Data and Goliath’s Big Idea; book page; The Trajectories of Government and Corporate Surveillance). The purchase route is now documented in the intelligence community’s own report on commercially available data (see the convergence table).
5. Testimony
- November 16, 2016, House Energy and Commerce, after the Mirai botnet’s attack on Dyn: “everything is now a computer,” and the case for a new federal cybersecurity agency (testimony).
- November 1, 2017, House Subcommittee on Digital Commerce and Consumer Protection, on Equifax and the internet of things (testimony; official PDF).
6. Crown Sterling, as the record has it
Crown Sterling paid $115,000 for a sponsored talk at Black Hat 2019, claimed to have broken RSA encryption, and was heckled. Schneier called the company “complete and utter snake oil” (The Doghouse: Crown Sterling, Sep 5 2019). Crown Sterling then sued Black Hat’s parent company, UBM, for breach of the sponsorship contract and named ten anonymous “John Doe” hecklers, calling the reception a “defamatory smear campaign” (The Register, Aug 26 2019; CyberScoop; Techdirt). Schneier was not a defendant; in his own post he only joked that the company might “file a meritless lawsuit against me instead.” The suit was settled on confidential terms in April 2020 (CyberScoop, Apr 22 2020).
Related
- NSA and Snowden · Encryption trade-off · Convergence table
- Watching the Watchers · What the Data Shows (the five-person surveillance core)