DES_attack

Algorithm

DES is an encryption algorithm based on substitution. In this repository we show three different attacks to this algorithm:

• Known ciphertext and chosen plaintext: attack using a set of frequently used passwords rockyou.txt that has to be downloaded from https://www.kaggle.com/wjburns/common-password-list-rockyoutxt/version/1;
• Known ciphertext and chosen plaintext: attack bruteforcing all the possible passwords;
• known ciphertext: bruteforce over the keys to decrypt the ciphertext, the obtained plaintext is chosen as correct if it has a reasonable low distance from a frequent password of rockyou.txt.

Implementation

The first attack is implemented both in Java and in C++, while the second and the third only in Java. All those implementations include a parallelized version respectively with C++ Threads and Java Threads.

C++ version

To run the c++ version you have to move to the relative folder and then in the parallel or sequential. To run the tests you can execute the relative bash script

bash test.sh

If you want to execute a custom test run:

• parallel version

g++ main.cpp -pthread -lcrypt -o mainCpp
./mainCpp num_threads plaintext_target

• sequential version

g++ main.cpp -lcrypt -o mainCpp
./mainCpp plaintext_target

Results

The performance improvements are significant given that the problem is embrassingly parallel. Chek the results on the relative csv files.

Contributors

Contributions are made by Lorenzo Macchiarini and Andrea Leonardo for the course Parallel Computing of the Master Degree in Software Engineering.