keyanalyze is designed to analyze keyrings in the OpenPGP format (PGP and GnuPG). It looks at properties of connectivity to generate strongly-connected set analysis, as well as some arbitrary statistics including a "mean shortest distance" calculation to show the most connected keys. This code is also used to create a report based on an extremely large keyset once per month.
RFC 2015 defines a proposed Internet standard for sending PGP-encrypted email. This PGP/MIME has been incorporated into several MUAs such as Mutt and (with the AEGYPTEN project) KMail. However, a lot of email clients still don't support it. pgp-mime-handler can decrypt/verify such messages via a pipe, so it can be used as an email filter in many programs or scripts.
MuPO (Multi-Purpose-Organizer) is a powerful PIM application for desktop and PDA systems. It features a hierarchical todo-list and notes, appointments, a project-time recorder, a calendar, recurring items, and more. It is fully searchable, and it includes a tool to sync several mupo-files. You can use it on an Agenda PDA, Compaq iPaq, or on a PC running Linux or Windows. Items can be encrypted.
RC-Crypt can be used to encrypt or decrypt data using the RC5 algorithm. It operates on 128-bit data blocks, adding random characters for padding if necessary. The key size can be chosen by the user, but 64 bits or greater is recommended. It has many input/output options, making this a versatile piece of software suitable for embedding into scripts.
The Pseudo Random Number Generator Daemon (PRNGD) offers an EGD compatible interface for obtaining random data. It is intented to be used as an entropy source to feed other software, especially software based on OpenSSL. Like EGD, it calls system programs to collect entropy. Unlike EGD, it does not generate a pool of random bits that can be called from other software. Instead, it feeds the bits gathered into the OpenSSL PRNG, from which the "random bits" are obtained when requested. This way, PRNGD is never drained and can never block (unlike EGD), so it is also suitable to seed inetd-started programs. It also features a seed-save file, so that it is immediately usable after system start.
OpenPGP Webmail is a set of PHP scripts which allows anonymous Web users to send encrypted email to anyone with PGP or GPG keys. It is designed to run over SSL, and has a key search facility built in. GnuPG is required to do the encryption. The project is now abandonware. Anyone can take it over if they like.
GNU Anubis is an SMTP message submission daemon. It represents an intermediate layer between the mail user agent (MUA) and mail transport agent (MTA), receiving messages from the MUA, applying to them a set of predefined changes, and finally inserting modified messages into an MTA routing network. The set of changes applied to a message is configurable on a system-wide and per-user basis. The built-in configuration language used for defining sets of changes allows for considerable flexibility and is easily extensible.
RSA-Haskell is a collection of command-line cryptography tools and a cryptography library written in Haskell. It is intended to be useful to anyone who wants to secure files or communications or who wants to incorporate cryptography in their Haskell application. The libraries include Haskell implementations of SHA1, EME-OAEP, EMSA-PSS, MGF, RSAES-OAEP, and RSA-PSS. These standards implement signature/verification, strong cryptography, and hashing.