Java SHA-256.java

/*
Cryptographic hash functions are mathematical operations run on digital data; 
by comparing the computed hash (i.e., the output produced by executing a hashing algorithm) to a known and expected hash value, 
a person can determine the data's integrity. 
For example, computing the hash of a downloaded file and comparing the result to a previously published hash result can show whether the download has been modified or tampered with. 
In addition, cryptographic hash functions are extremely collision-resistant; 
in other words, it should be extremely difficult to produce the same hash output from two different input values using a cryptographic hash function.

Secure Hash Algorithm 2 (SHA-2) is a set of cryptographic hash functions designed by the National Security Agency (NSA). 
It consists of six identical hashing algorithms (i.e., SHA-256, SHA-512, SHA-224, SHA-384, SHA-512/224, SHA-512/256) with a variable digest size. 
SHA-256 is a 256-bit (32 byte) hashing algorithm which can calculate a hash code for an input of up to 264 - 1 bits. 
It undergoes 64 rounds of hashing and calculates a hash code that is a 64-digit hexadecimal number.

Given a string, s, print its SHA-256 hash value.

Input Format

A single alphanumeric string denoting s.

Constraints
    * 6 <= |s| <= 20
    * String s consists of English alphabetic letters (i.e., [a-zA-Z] and/or decimal digits (i.e., 0 through 9) only.

Output Format
Print the SHA-256 encryption value of  on a new line.

Sample Input 0
HelloWorld

Sample Output 0
872e4e50ce9990d8b041330c47c9ddd11bec6b503ae9386a99da8584e9bb12c4

Sample Input 1
Javarmi123

Sample Output 1
f1d5f8d75bb55c777207c251d07d9091dc10fe7d6682db869106aacb4b7df678
*/



// Other's Solution:
import java.security.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
        /* Read and save the input String */
        Scanner scan = new Scanner(System.in);
        String str = scan.next();
        scan.close();
        
        try {
            /* Encode the String using SHA-256 */
            MessageDigest md = MessageDigest.getInstance("SHA-256");
            md.update(str.getBytes());
            byte[] digest = md.digest();
            
            /* Print the encoded value in hexadecimal */
            for (byte b : digest) {
                System.out.format("%02x", b);
            }
        } catch (Exception ex) {
            throw new RuntimeException(ex);
        }
    }
}