The Cornell Data Exchange: CODEX is a key distribution system. It is designed for applications with a moderate number of clients (tens or hundreds) requesting keys that change often but not continuously (on the scale of minutes to hours). It employs the RSA and ElGamal encryption schemes, as well as techniques such as threshold cryptography and proactive secret sharing.
fragroute intercepts, modifies, and rewrites egress traffic destined for a specified host, implementing most of the attacks described in the Secure Networks "Insertion, Evasion, and Denial of Service: Eluding Network Intrusion Detection" paper.
Geheimnis is a KDE application that "wraps" around GPG/PGP's irksome command-line interface and makes it easier for users to use these programs.
GNU Privacy Guard DNS Keyserver Client
GNU Privacy Guard DNS Keyserver Client is a plugin to GNU Privacy Guard to connect to DNS-based key servers.
GnuPG.pm is a Perl module that interface with the Gnu Privacy Guard using the coprocess hooks provided by gpg. The communication mechanism used is shared memory and a status file descriptor.
gpgdir is a perl script that uses the CPAN GnuPG module to encrypt and decrypt directories using a gpg key specified in ~/.gpgdirrc.
The keychain script makes handling RSA and DSA keys both convenient and secure. It acts as a front-end to ssh-agent, allowing you to easily have one long-running ssh-agent process per system, rather than per login session.
kgpg is a simple, free, open source KDE frontend for gpg.
KPGPCrypt is Key Managment for PGP 5.xx, PGP 6.xx and GPG 1.xx. It supports Add, Delete, Sign, Revoke, Disable Enable keys in graphical environment.
A reasonable way to achieve a long term backup of OpenPGP (GnuPG, PGP, etc) keys is to print them out on paper. Due to metadata and redundancy, OpenPGP secret keys are significantly larger than just the "secret bits". In fact, the secret key contains a complete copy of the public key. Since the public key generally doesn't need to be backed up in this way (most people have many copies of it on various keyservers, Web pages, etc), only extracting the secret parts can be a real advantage. Paperkey extracts just those secret bytes and prints them. To reconstruct, you re-enter those bytes (whether by hand or via OCR), and paperkey can use them to transform your existing public key into a secret key.
PinePgp is set of display and sending filters which enables pine to send and receive signed and/or encrypted e-mails.
Smart Sign provides smartcard-based "digital signature" and "local authentication" security services. It relies on a working Certification Authority that issues a public key certificate for the user. Read more
Secure Remote Password protocol is a password-based authentication and key exchange mechanism where no information about the password is leaked during the authentication process.
SSH Askpass Keyring
SSH Askpass Keyring is an alternative ssh-askpass utility with support for the gnome-keyring.
ssl-audit helps you find weak RSA/DSA keys as they are produced by corrupt Debian OpenSSL packages. Since this problem may affect other platforms indirectly, ssl-audit also supports Windows and Mac OS X.
This application is a graphical user interface to OpenSSL, RSA/DSA public keys, certificates, signing requests and revokation lists. It uses the OpenSSL library and a Berkeley DB for key and certificate storage. It supports importing and exporting keys and PEM DER PKCS8 certificates, signing and revoking of PEM DER PKCS12, and the selection of x509v3 extensions. A tree view of certificates is presented.