Crypto Crumple Zones: Protecting Encryption in a Time of Political Uncertainty

Governments around the world are demanding more access to encrypted data, but it has been difficult to build a system that allows the authorities some access without providing unlimited access in practice. And so the public policy debate around encryption has been framed as a binary choice between two absolutist positions: either we allow law enforcement no access at all to encrypted data, or we must effectively give them complete, unrestricted access to all our communications. In the first half of this talk, I begin by summarizing the current state of the debate around the availability of strong end-to-end encryption. How did we get here, and why did key escrow fail in the 90’s? What are the current arguments for and against strong end-to-end crypto? What are the motivations of the various parties on each side of the debate? Where is public opinion on this issue? What is the current status quo—in the US, in Europe, and in developing nations around the world?

In the second half of the talk, I argue that the crypto and security community should investigate better technical solutions to provide more security for people in countries where unbreakable, end-to-end encryption is already illegal (e.g., India) or where it may soon be banned (the UK). As a first step toward this goal, I present new constructions that maximize user privacy while still allowing the authorities some limited “exceptional access” to encrypted data. I present two new constructions for crumpling cryptographic keys to make it possible— although arbitrarily expensive—for a government to recover the plaintext for targeted messages. In contrast to previous work on this topic (e.g., key escrow), our approach places most of the responsibility for achieving exceptional access on the government rather than on the users or developers of cryptographic tools. I conclude with some thoughts on remaining challenges and directions for future work, including: issues of internationalization; creating disincentives for misuse; and some possible countermeasures.