Openssl

At first, the idea of encrypting more of the metadata found inside the initial packet (the “ClientHello”) of a TLS connection may seem simple and obvious, but there are of course reasons that this wasn’t done right from the start. In this post I will describe the flow of a connection using Encrypted Client Hello (ECH) to protect the metadata fields, and present a working code example using a fork of CPython built with DEfO project’s OpenSSL fork to connect to ECH-enabled HTTPS servers. [Read More]

The Encrypted Client Hello (ECH) mechanism draft-spec is a way to plug a few privacy-holes that remain in the Transport Layer Security (TLS) protocol that’s used as the security layer for the web. OpenSSL is a widely used library that provides an implementation of the TLS protocol. The DEfO project has developed an implementation of ECH for OpenSSL, and proof-of-concept implementations of various clients and servers that use OpenSSL, and other TLS libraries, as a demonstration and for interoperability testing. [Read More]

Encrypted ClientHello (ECH) plugs a privacy-hole in TLS, hiding previously visible details from network observers. The most important being the name of the web-site the client wishes to visit (the Server Name Indication or SNI). This can be a major privacy leak, like when accessing a dissident news source hosted on a Content Delivery Network (CDN). A visible domain name also provides a straightforward method for censors to block websites and internet services. [Read More]

Day Two of the 116th IETF meeting in Yokohama Japan. For the rundown on Day One, see my daily report. The OHAI Working Group has submitted the core draft of Oblivious HTTP Application Intermediation to the RFC Editor for editorial finalization and publication. OHAI is designed to support transational uses of the HTTP protocol that seek IP address privacy (by means of a relay pair, one associated with the client and one associated with the target resource). [Read More]

In terms of potential impact on Internet Freedom, it’s been a banner year at the Internet Engineering Task Force (IETF). QUIC (featuring the improved privacy and security of TLS1.3) reached Proposed Standard status, with implementations and rollouts from every major vendor on both server and client, and with multiple open source toolkit options for developers. Encrypted Client Hello for TLS1.3 gained traction via the DEfO project that, through pull requests, makes a huge privacy enhancement easily available to the major security library (OpenSSL) underpinning the Internet’s most important service engines (nginx, apache, lighttpd, haproxy on the server, even curl on the client). [Read More]

As part of the DEfO project, we have been working on accelerating the development Encrypted Client Hello (ECH) as standardized by the IETF. ECH is the next step in improving Transport Layer Security (TLS). TLS is one of the basic building blocks of the internet, it is what puts the S in HTTPS. The ECH standard is nearing completion. That is exciting because ECH can encrypt the last plaintext TLS metadata that it is possible to encrypt. [Read More]

Hardware Security Modules (aka Smartcards, chipcards, etc) provide a secure way to store and use cryptographic keys, while actually making the whole process a bit easier. In theory, one USB thumb drive like thing could manage all of the crypto keys you use in a way that makes them much harder to steal. That is the promise. The reality is that the world of Hardware Security Modules (HSMs) is a massive, scary minefield of endless technical gotchas, byzantine standards (PKCS#11! [Read More]