Tomb is an 100% free and open source system for file encryption on Linux, facilitating the backup of secret files. Tomb is written in code that is easy to review and links commonly shared components.

Tomb generates encrypted storage folders to be opened and closed using their associated keyfiles, which are also protected with a password chosen by the user.

A tomb is like a locked folder that can be safely transported and hidden in a filesystem; its keys can be kept separate, for instance keeping the tomb file on your computer harddisk and the key files on a USB stick.

Tomb is a simple tool to manage encrypted storage on GNU/Linux, from the hashes of the dyne:bolic nesting mechanism.

Simulate 12 different Enigma models in your browser.

On-line tool to learn about cryptography. Supports a number of encryption methods (including Enigma).
An off-line version can be found on http://www.cryptool.org/

The idea behind its design is that passphrase memorized by the user, along with their email address, can act as a complete, portable basis for a persistent public key identity and provide a full substitute for other key pair models, such as having the key pair stored on disk media (the PGP approach).

Found via http://blog.cryptographyengineering.com/2014/08/whats-matter-with-pgp.html

As a reaction to the announced end of the development of the encryption software TrueCrypt, Sirrix AG, Germany, plans to publish an open-source version of TrustedDisk as successor of TrueCrypt.

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.

A neat paper model of the german Enigma machine. An emulator for Android is available from the same author.

Small SSH server and client.

Discussion of methods to solve the sparse linear systems over GF(p^n) encountered in factoring and discrete logarithm problems, by B. A. LaMacchia and A. M. Odlyzko.

Looks like an interesting book.