Encryption plays a vital role in modern communication systems to ensure the security and confidentiality of data being transmitted. As data volumes continue to grow, the need for faster encryption algorithms is becoming increasingly important. One way to achieve faster encryption is by leveraging parallel processing techniques.

In this blog post, we will explore how to implement parallel encryption algorithms using std::jthread, a multi-threading library introduced in C++20. We will focus on implementing a parallel version of the Advanced Encryption Standard (AES) algorithm.

The AES Algorithm

AES is a widely adopted encryption algorithm that provides strong security and performance. It works on blocks of data, each of which is 128 bits (16 bytes) in size. The algorithm uses a secret key to perform encryption and decryption operations.

Parallelization using std::jthread

To parallelize the AES algorithm, we can divide the input data into smaller blocks and process them concurrently using multiple threads. std::jthread provides a convenient way to create and manage threads in C++.

Here’s an example code snippet of how we can use std::jthread to parallelize the encryption process:

#include <iostream>
#include <vector>
#include <thread>

void encryptBlock(const std::vector<uint8_t>& block, const std::vector<uint8_t>& key)
{
    // Encryption logic goes here
    // ...
}

void parallelEncrypt(const std::vector<uint8_t>& input, const std::vector<uint8_t>& key)
{
    const std::size_t numThreads = std::thread::hardware_concurrency();
    const std::size_t blockSize = input.size() / numThreads;
    std::vector<std::jthread> threads;

    for (std::size_t i = 0; i < numThreads; ++i)
    {
        const std::size_t start = i * blockSize;
        const std::size_t end = start + blockSize;
        const std::vector<uint8_t> block(input.begin() + start, input.begin() + end);
        
        // Create a thread to encrypt the block
        threads.emplace_back([block, key]()
        {
            encryptBlock(block, key);
        });
    }

    // Wait for all threads to finish execution
    for (auto& thread : threads)
    {
        thread.join();
    }
}

int main()
{
    std::vector<uint8_t> input = { /* ... */ };
    std::vector<uint8_t> key = { /* ... */ };
    
    parallelEncrypt(input, key);

    return 0;
}

In this example, we divide the input data into smaller blocks, each encrypted by a separate std::jthread. The encryptBlock function represents the logic for encrypting a single block of data using the provided key. The parallelEncrypt function distributes the blocks across multiple threads and waits for all threads to complete before returning.

Conclusion

Parallelization can significantly improve the performance of encryption algorithms by leveraging the computational power of modern multi-core processors. Using std::jthread, we can easily implement parallel versions of encryption algorithms like AES.

When implementing parallel algorithms, it’s essential to consider thread safety, synchronization, and load balancing. Depending on the specific requirements and constraints, different parallelization strategies may yield varying levels of performance improvement.

By taking advantage of parallel processing techniques, we can achieve faster encryption and enhance the overall security of our systems.

#encryption #parallelization