Identify anything. pyWhat easily lets you identify emails, IP addresses, and more. Feed it a .pcap file or some text and it'll tell you what it is!
Chepy is a python library with a handy cli that is aimed to mirror some of the capabilities of CyberChef. A reasonable amount of effort was put behind Chepy to make it compatible to the various functionalities that CyberChef offers, all in a pure Pythonic manner. There are some key advantages and disadvantages that Chepy has over Cyberchef. The Cyberchef concept of stacking different modules is kept alive in Chepy.
Fully automated decryption tool using natural language processing & artifical intelligence, along with some common sense. Input encrypted text, (hopefully) get the decrypted text back. You don't know, you just know it's possibly encrypted. Ciphey will figure it out for you. Ciphey can solve most things in 3 seconds or less.
Docs: https://docs.ciphey.online/en/latest
Ciphey can even be imported as a module in your own Python code!
It's basically the cryptographer's workbench I was going to write while I was in Pittsburgh.
CyberChef is a simple, intuitive web app for carrying out all manner of "cyber" operations within a web browser. These operations include simple encoding like XOR or Base64, more complex encryption like AES, DES and Blowfish, creating binary and hexdumps, compression and decompression of data, calculating hashes and checksums, IPv6 and X.509 parsing, changing character encodings, and much more.
The tool is designed to enable both technical and non-technical analysts to manipulate data in complex ways without having to deal with complex tools or algorithms. It was conceived, designed, built and incrementally improved by an analyst in their 10% innovation time over several years.
Online copy: https://gchq.github.io/CyberChef/
The OpenBSD project produces a FREE, multi-platform 4.4BSD-based UNIX-like operating system. Our efforts emphasize portability, standardization, correctness, proactive security and integrated cryptography. As an example of the effect OpenBSD has, the popular OpenSSH software comes from OpenBSD.
Daniel J. Berstein's homepage. There are tools and code galore here - check it out!
Off-the-Record (OTR) Messaging allows you to have private conversations over instant messaging by providing encryption, authentication, deniability and perfect forward secrecy.
An open-source utility for Linux that uses an attached webcam to seed the kernel's random number generator for cryptographic purposes.
An open source utility for Linux that seeds the kernel's random number generator with data pulled from an attached microphone.
The full text of The Handbook of Applied Cryptography, one of the best textbooks available in the field. The original authors have gotten permission from the publisher to put the text online as sets of PostScript and .pdf files for anyone to download and share.