The Entropy Key is a small, unobtrusive and easily installed USB stick that generates high-quality random numbers, or entropy.
The Entropy Key contains two high-quality noise generators, and an ARM Cortex CPU that actively measures, checks and confirms all generated random numbers, before encrypting them and sending them to the server. It also actively detects attempts to corrupt or sway the device. It aims towards FIPS-140-2 Level 3 compliance with some elements of Level 4, including tamper-evidence, tamper-proofing, role-based authentication, and environmental attacks. If it detects that one of its two generators has failed, may be about to fail, or if it detects a physical attack, it will automatically shut down.
£36, but currently (Jan 2015) out of stock.

The USB armory from Inverse Path is an open source hardware design, implementing a flash drive sized computer.

Detailed description of the shellshock vulnerability and the lessions to be learned from it.

Time-based one-time-password (TOTP, RFC6238) generator for Java mobile edition.

Blog about Programming, Theory, and Math, written by John Meacham.

Information about the on-going audit of the TrueCrypt disk encryption software.

Blog article about capability-based security. Includes a link to Jonathan Rees' W7 system http://www.cap-lore.com/CapTheory/Rees/Rees.html

Manual of the GnuTLS (transport layer security) library, which appears to provide a good overview of TLS/SSL.

Our Mission:To bring the world our unique end-to-end encrypted protocol and architecture that is the 'next-generation' of private and secure email.

Collection of software to make NSA's spying more difficult.