DER ASCII is a small human-editable language to emit DER (Distinguished Encoding Rules) or BER (Basic Encoding Rules) encodings of ASN.1 structures and malformed variants of them.
GAP is a system for computational discrete algebra, with particular emphasis on Computational Group Theory. GAP provides a programming language, a library of thousands of functions implementing algebraic algorithms written in the GAP language as well as large data libraries of algebraic objects. See also the overview and the description of the mathematical capabilities. GAP is used in research and teaching for studying groups and their representations, rings, vector spaces, algebras, combinatorial structures, and more. The system, including source, is distributed freely. You can study and easily modify or extend it for your special use.
The Octave syntax is largely compatible with Matlab. The Octave interpreter can be run in GUI mode, as a console, or invoked as part of a shell script. More Octave examples can be found in the wiki.
SageMath is a free open-source mathematics software system licensed under the GPL. It builds on top of many existing open-source packages: NumPy, SciPy, matplotlib, Sympy, Maxima, GAP, FLINT, R and many more. Access their combined power through a common, Python-based language or directly via interfaces or wrappers.
KeePassX is an application for people with extremly high demands on secure personal data management. It has a light interface, is cross platform and published under the terms of the GNU General Public License.
KeePass Cross-Platform Community Edition
The thing computers can do best is storing information.
You shouldn't waste your time trying to remember and type your passwords.
KeePassXC can store your passwords safely and auto-type them into your everyday websites and applications.
Free cross-platform password manager compatible with KeePass
Delta Chat is a modern messenger. It is like email in a new dress. Just better, safer and user-optimised.
GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP). GnuPG allows to encrypt and sign your data and communication, features a versatile key management system as well as access modules for all kinds of public key directories. GnuPG, also known as GPG, is a command line tool with features for easy integration with other applications.
Gpg4win enables users to securely transport emails and files with the help of encryption and digital signatures. Encryption protects the contents against an unwanted party reading it. Digital signatures make sure that it was not modified and comes from a specific sender.
GPGrelay is a small email-relaying server that uses GnuPG (the GNU Privacy Guard) to sign/encrypt (SMTP-Relay) or verify/decrypt (POP3-/IMAP-Relay) emails. This enables many email-clients to send and receive emails that are PGP-MIME conform.
GPGMail, GPG Keychain, GPG Services, MacGPG
OpenKeychain for Android helps you communicate more privately and securely, compatible with the OpenPGP standard.
pgpdump is a PGP packet visualizer which displays the packet format of OpenPGP (RFC 4880) and PGP version 2 (RFC 1991).
JCTerm(JCraft's Term) is a pure Java VT100 terminal emulator for SSH2. This terminal emulator also allows you to enjoy port forwarding, X11 forwarding, etc.
OpenSSH is the premier connectivity tool for remote login with the SSH protocol. It encrypts all traffic to eliminate eavesdropping, connection hijacking, and other attacks. In addition, OpenSSH provides a large suite of secure tunneling capabilities, several authentication methods, and sophisticated configuration options.
PuTTY is an SSH and telnet client, developed originally by Simon Tatham for the Windows platform. PuTTY is open source software that is available with source code and is developed and supported by a group of volunteers.
BoringSSL is a fork of OpenSSL that is designed to meet Google's needs.
https://github.com/square/certigo - Certigo is a utility to examine and validate certificates to help with debugging SSL/TLS issues.
$ go get -u github.com/square/certigo -OR- $ brew install certigo
CFSSL is CloudFlare's PKI/TLS swiss army knife. It is both a command line tool and an HTTP API server for signing, verifying, and bundling TLS certificates. It requires Go 1.6+ to build.
GnuTLS is a secure communications library implementing the SSL, TLS and DTLS protocols and technologies around them. It provides a simple C language application programming interface (API) to access the secure communications protocols as well as APIs to parse and write X.509, PKCS #12, and other required structures.
LibreSSL is a version of the TLS/crypto stack forked from OpenSSL in 2014, with goals of modernizing the codebase, improving security, and applying best practice development processes.
OpenSSL is a robust, commercial-grade, and full-featured toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols. It is also a general-purpose cryptography library.
A command-line reference-implementation client for SSL Labs APIs, designed for automated and/or bulk testing.
Transparent Data Encryption
CryFS encrypts your files, so you can safely store them anywhere. It works well together with cloud services like Dropbox, iCloud, OneDrive and others.
eCryptfs is a POSIX-compliant enterprise cryptographic stacked filesystem for Linux. eCryptfs stores cryptographic metadata in the header of each file, so that encrypted files can be copied between hosts; the file will be decrypted with the proper key in the Linux kernel keyring. There is no need to keep track of any additional information aside from what is already in the encrypted file itself. You may think of eCryptfs as a sort of “gnupg as a filesystem”.
EncFS provides an encrypted filesystem in user-space. It runs in userspace, using the FUSE library for the filesystem interface.
gocryptfs uses file-based encryption that is implemented as a mountable FUSE filesystem.
LUKS is the standard for Linux hard disk encryption. By providing a standard on-disk-format, it does not only facilitate compatibility among distributions, but also provides secure management of multiple user passwords. In contrast to existing solution, LUKS stores all setup necessary setup information in the partition header, enabling the user to transport or migrate his data seamlessly.
TrueCrypt is a discontinued source-available freeware utility used for on-the-fly encryption (OTFE). It can create a virtual encrypted disk within a file, or encrypt a partition or the whole storage device (pre-boot authentication).
VeraCrypt is a free disk encryption software brought to you by IDRIX (https://www.idrix.fr) and that is based on TrueCrypt 7.1a.
1-click IPSEC VPN in the Cloud