ACL2 is a mathematical logic, programming language, and mechanical theorem prover based on the applicative subset of Common Lisp. It is an "industrial-strength" version of the NQTHM or Boyer/Moore theorem prover, and has been used for the formal verification of commercial microprocessors, the Java Virtual Machine, interesting algorithms, and so forth.
Bugs Dynamic Cryptography is a private key cryptography algorithm. The package includes a C Library and many sample applications, including ones for file encryption, secure chatting, and login applications. The algorithm handles stream and block encryption, unlimited Keylength, and a strong key generator. Documentation and a developer HOWTO are included.
The Enhanced File Crypt/eXtended File Stealth System (EFC/XFSS) makes your uploaded files safe on the server so that no one can read them without knowing a few details to decipher the files. It generates different obfuscated names and encrypted files so no one will know what the original format or name was.
Enigmail is an extension for the mail client of Mozilla, Netscape 7.x, and Mozilla Thunderbird that allows users to access the authentication and encryption features provided by the popular GnuPG software. It can encrypt/sign mail when sending, decrypt/authenticate received mail, and import/export public keys. It supports both the inline PGP format and the PGP/MIME format, which can be used to encrypt attachments, and is cross-platform, although binaries are supplied only for a limited number of platforms. Enigmail uses inter-process communication to execute GPG to carry out encryption/authentication.
EverCrack is a cryptanalysis engine. The overall design goal is to systematically break down complex ciphers into their simplex components for cryptanalysis (by the kernel). The kernel consists of an algebraic design (comparison and reduction) for breaking uniliteral, monoalphabetic ciphers instantaneously. Currently, it can break a 4000-word cipher in milliseconds. EverCrack currently has multi-language support for the user interface and cracking encryption in other language dictionaries (English, German, French, Spanish, Italian, Swedish, Dutch, and Portuguese).
GNU SASL is an implementation of the Simple Authentication and Security Layer framework and a few common SASL mechanisms. SASL is used by network servers such as IMAP and SMTP to request authentication from clients, and in clients to authenticate against servers. The library includes support for the SASL framework (with authentication functions and application data privacy and integrity functions) and at least partial support for the CRAM-MD5, EXTERNAL, GSSAPI, ANONYMOUS, PLAIN, SECURID, DIGEST-MD5, LOGIN, NTLM, and KERBEROS_V5 mechanisms.
GNUnet is a peer-to-peer framework with focus on providing security. All peer-to-peer messages in the network are confidential and authenticated. The framework provides a transport abstraction layer and can currently encapsulate the network traffic in UDP, TCP, HTTP, HTTPS, or direct 802.11 (WLAN). GNUnet supports accounting to provide contributing nodes with better service. The services built on top of the framework include anonymous file sharing and a virtual network providing IPv4-IPv6 transition via protocol translation over the P2P network.