SHA-2 algorithms

This is my implementation of the SHA-2 hashing algorithms. Written in C++ and using C++23 features, making extensive use of templates and concepts. This is a learning exercise and has helped me better understard C++ templates as well as getting familiar with new C++ features. This program is not intended for any serious use nor does it have security in mind.

Reference: RFC6234

Algorithms implemented:

• sha-256
• sha-384
• sha-512

Usage

To compute the hash of a string just pass it as an argument

./mysha <message> <message2>...

This will print out the sha256 hash of each message

Building

Requirements:

• catch2 v3.5.4
• msd-cpp-utils v0.0.4

Documentation

namespace algorithms

contains all the algorithms in their individial sub-namespace. Each algorithm has a class called hash which is the main class that is used to calculate hashes.

For example algorithms::sha384::hash is the class that you will need to instantiate.

The API has been modelled after hashlib python standard library. Once you have an instance you call hash::update with a range of data, as many times as needed to exhaust all data. At the end you can call hash::digest() to calculate the final hash value.

Important to note that hash::digest() does not modify the state and if needed you can use hash::update again to add more data. Every time you call hash::digest() between 1 and 2 blocks will need to be processed. The size of each block for the algorithms is found from in the details class for each algorithm for example algorithms::sha384::details::block_size.

namespace integer

struct extended_integer<Unit, UnitCount>

An arbitrary precision unsigned integer. Comprised of multiple fundamental integer types, stored in contiguous space and with endianess that matches the host machine's architecture.

Type Unit: the fundamental integer type that will be used

Type UnitCount: the count of units that will be stored contiguously

Operations supported:

• All unsigned integer arithmetic operations (* / +)
• All Bitwise Operations (~ & | ^ >> <<)
• Conversion to decimal / hexadecimal

Additional operations supported:

• Convert to hexadecimal string
• Return underlying units (span of uint64_t)

Also because this integer adheres to the system's endianess, it can be loaded and dumped using msd_utils/endian.hpp.

This type will be further developed in the utilities library.

Compile using cmake

Assuming you have all requirements installed then just execute the following

mkdir build
cd build
cmake ../src
cmake --build .

Compile using cmake and conan

To install the requirements using conan in the build folder run

conan install src --output-folder build --build=missing -pr:a mingw

To build run

mkdir build
cd build
cmake ../src -D CMAKE_TOOLCHAIN_FILE=conan_toolchain.cmake
cmake --build .

Note: the requirements are only needed if you want to build the tests, otherwise pass -DBUILD_TESTS=FALSE to the first cmake command and it should build without a hitch.

Requirements are listed in conanfile.txt

If you want to install the requirements automatically using conan then run conan-build.sh (replace profile name in the script, if required). For windows users you should be able to just copy the commands one by one.

TODO

See TODO file.