What are the differences between various hash functions in C++?

What are the main differences between MD5, SHA-1, and SHA-256 hash functions?

MD5 is fast but not secure, SHA-1 is more secure but still vulnerable, while SHA-256 offers strong security and is slower.

Why is SHA-256 preferred over MD5 and SHA-1 for security applications?

SHA-256 is preferred because it has a larger bit size, making it more resistant to collision attacks compared to MD5 and SHA-1.

Can you explain how to implement these hash functions in C++?

Sure! You can use libraries like OpenSSL or Crypto++ to implement these hash functions in C++. Would you like a code example?

Yes, please provide a simple example of using SHA-256 in C++.

Here's a basic example using OpenSSL:

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

void sha256(const std::string &input, unsigned char output[SHA256_DIGEST_LENGTH]) {
    SHA256(reinterpret_cast<const unsigned char*>(input.c_str()), input.size(), output);
}

int main() {
    std::string data = "Hello, World!";
    unsigned char hash[SHA256_DIGEST_LENGTH];
    sha256(data, hash);
    for(int i = 0; i < SHA256_DIGEST_LENGTH; i++) {
        std::cout << std::hex << std::setw(2) << std::setfill('0') << (int)hash[i];
    }
    return 0;
}

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