How do I use SHA-256 in C++?

How do I use SHA-256 in C++?

To use SHA-256 in C++, you can utilize libraries like OpenSSL or Crypto++. Would you like a code example?

Yes, please provide a code example using OpenSSL.

Here's a simple example:

#include <openssl/sha.h>
#include <iostream>
#include <iomanip>
#include <string>

std::string sha256(const std::string str) {
    unsigned char hash[SHA256_DIGEST_LENGTH];
    SHA256_CTX sha256;
    SHA256_Init(&sha256);
    SHA256_Update(&sha256, str.c_str(), str.size());
    SHA256_Final(hash, &sha256);
    std::stringstream ss;
    for(int i = 0; i < SHA256_DIGEST_LENGTH; i++) {
        ss << std::hex << std::setw(2) << std::setfill('0') << (int)hash[i];
    }
    return ss.str();
}

int main() {
    std::string data = "Hello, World!";
    std::cout << "SHA-256: " << sha256(data) << std::endl;
    return 0;
}

This will output the SHA-256 hash of "Hello, World!".

What if I want to hash a file instead of a string?

You can read the file in chunks and update the SHA-256 context with each chunk. Would you like to see that code?