jjeong

일단 keep.

https://github.com/parkjs814/AlgorithmVisualizer

그냥 인터넷에 돌아 다니는 코드 가져가 기록해 봤습니다.

[코드]

public class HashGenerator {

  public static void main (String[] args)
    throws NoSuchAlgorithmException {
    
    String md2 = getHash("test", "md2");
    String md5 = getHash("test", "md5");
    String sha1 = getHash("test", "sha1");
    String sha256 = getHash("test", "sha-256");
    String sha384 = getHash("test", "sha-384");
    String sha512 = getHash("test", "sha-512");

    // “MD2″, “MD5″, “SHA1″, “SHA-256″, “SHA-384″, “SHA-512″
    System.out.println("MD2     : [" + md2 + "](" + md2.length() + ")");
    System.out.println("MD5     : [" + md5 + "](" + md5.length() + ")");
    System.out.println("SHA1    : [" + sha1 + "](" + sha1.length() + ")");
    System.out.println("SHA-256 : [" + sha256 + "](" + sha256.length() + ")");
    System.out.println("SHA-384 : [" + sha384 + "](" + sha384.length() + ")");
    System.out.println("SHA-512 : [" + sha512 + "](" + sha512.length() + ")");
  }

  public static String getHash(String message, String algorithm)
    throws NoSuchAlgorithmException {
    
    try {
      byte[] buffer = message.getBytes();
      MessageDigest md = MessageDigest.getInstance(algorithm);
      md.update(buffer);
      byte[] digest = md.digest();
      String hex = "";
      
      for(int i = 0 ; i < digest.length ; i++) {
        int b = digest[i] & 0xff;
        if (Integer.toHexString(b).length() == 1) hex = hex + "0";
        hex  = hex + Integer.toHexString(b);
      }
      
      return hex;
    } catch(NoSuchAlgorithmException e) {
      e.printStackTrace();
    }
    
    return null;
  }
}

[결과]