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ASCON Suite

This repository builds a number of useful cryptographic primitives around the ASCON permutation.

API's are provided for the following areas:

• Authenticated Encryption with Associated Data (AEAD)
• Hashing
• Pseudorandom Function (PRF)
• Message Authentication Code (MAC)
• HMAC-based Key Derivation Function (HKDF)
• Hashed Message Authentication Code (HMAC)
• ISAP AEAD Mode with Side Channel Protections
• Keyed Message Authentication Code (KMAC)
• Password-Based Key Derivation Function (PBKDF2)
• Pseudorandom Number Generation (PRNG)
• Synthetic Initialization Vector (SIV)
• Extensible Output Functions (XOF)
• Direct Access to the ASCON Permutation

See the HTML documentation for more information on the suite.

Update (November 2024)

NIST has released the Initial Public Draft of NIST SP 800-232, which defines the proposed standard version of ASCON. There are some differences with the final round ASCON version from the lightweight cryptography competition:

• The suite of core algorithms has been reduced to four: ASCON-AEAD128, ASCON-Hash256, Ascon-XOF128, and ASCON-CXOF128.
• Little-endian representation of words instead of the original big-endian.
• Changed round constants and initialization vectors.
• Extension of the ASCON permutation to 16 rounds for future use.
• A new customizable XOF function, ASCON-CXOF128.

This repository currently implements the final round version of ASCON, not the proposed NIST standard. I am studying the proposed standard and am working to modify this library to implement the standard version.

The original final round version of ASCON Suite has been check-pointed in the final-round branch. Work on the proposed standard is in the proposed-standard branch, which will be merged into master once it matures.

Building

ASCON Suite uses cmake to build, so you will need to have that installed. Here is the simplest method to compile, test, and install the library:

mkdir build
cd build
cmake ..
make
make test
sudo make install

To build with a cross-compiler, set the "CC" and "CMAKE_C_FLAGS" variables when invoking cmake:

mkdir build
cd build
CC="avr-gcc" cmake -DMINIMAL=ON -DCMAKE_C_FLAGS="-mmcu=atmega2560" ..
make

Note carefully the placement of environment variables before the "cmake" command name, and the cmake variables specified with "-D" after.

The MINIMAL option suppresses the compilation of shared libraries, examples, and test programs, which may not compile for embedded microcontrollers due to missing libc functions or other platform constraints. Only the static library libascon_static.a is built in the minimal configuration.

If you are having problems compiling the assembly code backends, then I will need some extra information to help diagnose the problem. Navigate to the "test/compiler" directory and follow the instructions in the README.md file there.

Arduino

This repository can be used as a library with the Arduino IDE by copying the entire contents to "libraries/ascon-suite" in your sketchbook directory.

History

The functionality in this library was originally prototyped in the LWC Finalists repository. This repository extracts and expands the ASCON-specific parts of the original repository.

Contact

For more information on this code, to report bugs, or to suggest improvements, please contact the author Rhys Weatherley via email.