These are tools I've written to practice breaking ciphers.
CrappyCrypto contains my own versions of cryptographic algorithms that I have written to attack. They are not intentionally insecure, but I am not confident in stating that they are hardened against modern attacks. I have had security training in the past, have spent a number of years building threat models and fixing security issues, and have studied cryptography since 1991. I am quite confident in not being confident.
I first wrote the Skipjack code in 1998. Surprisingly, it built without errors in Visual Studio 2010. I have since tried to modernize it to modern C++ in VS2015.
Caveat: This code is portable, but due to variances in how arguments are passed to main() in C++, encoding
matters. For example, by default, file names are passed as ANSI (in the current code page) to main() in
Windows, and passed directly to fopen(). Linux will use UTF-8 by default. In general this will do what is
expected. However, keys are different. Since CrappyCrypto operates directly on the argv data,
non-ASCII keys will cause problems. For example, on Windows, the Euro '€' will be passed as a two byte
ANSI character to main(), and the key built from that. On Linux, the UTF-8 encoding of U+20AC is passed,
which is three bytes. The result is that data encoded on one platform might not be correctly decodable
on another without some care.
UTF-8 correctness is something that I am actively thinking about, and have an idea on the general portable solution for the above issue, but I want to reflect on whether it is the best approach for all of my projects before I commit to it.
CrappyCrypto has a dependency on the PortableRuntime library.
Toby Jones (www.turbohex.com, ace.roqs.net)