This repository consists of experiments on a Few Quantum Cryptanalysis Techniques.
The folder structure is as follows:

• ChaCha implementation
  • classical chacha.c: Classical ChaCha cipher implementation in C
  • classical with addition.ipynb: Notebook for classical ChaCha cipher implementation; easier to vary the number of bits in word size and constants
  • quantum rewired circuit.ipynb: Our Final Quantum ChaCha implementation (uses Cuccaro et al.'04 for addition modulo $2^n$, CNOT for XOR operations. rewiring for shift operations).
  • qubit and gate count.ipynb: Given a particular bit size, calculates the qubit count and depth of the circuit
• ChaCha cryptanalysis
  • ID OD bias.ipynb: given a particular input difference and output difference position, generates the output difference
• Finding linear approximations
  • classicalSmallGIFT.c: Generates the Linear approximation table for smallGIFT
  • quant_SmallGIFT_LC.py: Quantum implementation of smallGIFT cipher. Reference: https://github.com/tarunyadav/QuantumDifferentialAttack/blob/main/QuantumDifferentialCharacteristicsSearch.ipynb
  • SmallGIFT linear crypt_shared.ipynb: Finding linear approximations in smallGIFT cipher
  • getting distribution.ipynb: Generating the distribution of numbers for quantum smallGIFT
  • comparing classical and quantum histogram.ipynb: To visualise the classical and quantum histograms of frequency of linear approximations