Java MD5.java

/*
MD5 (Message-Digest algorithm 5) is a widely-used cryptographic hash function with a 128-bit hash value. Here are some common uses for MD5:
    * To store a one-way hash of a password.
    * To provide some assurance that a transferred file has arrived intact.

MD5 is one in a series of message digest algorithms designed by Professor Ronald Rivest of MIT (Rivest, 1994); however, the security of MD5 has been severely compromised, most infamously by the Flame malware in 2012. The CMU Software Engineering Institute essentially considers MD5 to be "cryptographically broken and unsuitable for further use".

Given an alphanumeric string, s, denoting a password, compute and print its MD5 encryption 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 MD5 encryption value of s on a new line.

Sample Input 0
HelloWorld

Sample Output 0
68e109f0f40ca72a15e05cc22786f8e6

Sample Input 1
Javarmi123

Sample Output 1
2da2d1e0ce7b4951a858ed2d547ef485
*/



// MD5 已过时，已被破解了，安全加密应使用 SHA-2
// Other's Solution:
import java.security.MessageDigest;
import java.util.Scanner;

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 MD5 */
            MessageDigest md = MessageDigest.getInstance("MD5");
            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);
        }
    }
}