What are cryptographic hash functions in C++11?

What are cryptographic hash functions in C++11?

Cryptographic hash functions are algorithms that take an input and produce a fixed-size string of bytes. In C++11, you can use libraries like OpenSSL or implement your own.

Can you give me an example of how to implement a SHA-256 hash function in C++11?

Sure! Here's a simple example using OpenSSL:

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

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();
}

What are the common use cases for cryptographic hash functions?

Common use cases include data integrity verification, password hashing, and digital signatures. They ensure that data has not been altered.

Are there any security concerns I should be aware of when using hash functions?

Yes, be cautious of collision attacks and always use a strong hash function like SHA-256. Avoid outdated algorithms like MD5.