Digest.java

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Digest {

	public static String md5(String str) {
		return digest(str, "MD5");
	}
	
	public static String sha(String str) {
		return digest(str, "SHA");
	}
	
	public static String sha512(String str) {
		return digest(str, "SHA-512");
	}
	
	public static String digest(String input, String algorithm) {
		return bytesToString(digest(input.getBytes(), algorithm));
	}
	
	public static byte[] digest(byte[] input, String algorithm) {
		try {
			MessageDigest digest = MessageDigest.getInstance(algorithm);
			digest.update(input);
			return digest.digest();
		} catch (NoSuchAlgorithmException e) {
      			e.printStackTrace();
		}
		return null;
	}

	public static String bytesToString(byte[] bytes) {
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < bytes.length; i++) {
			String str = Integer.toHexString(bytes[i] & 0xFF);
			if (str.length() == 1)
				sb.append('0');
			sb.append(str);
		}
		return sb.toString();
	}
	
	public static void main(String[] args) {
		System.out.println(Digest.sha512("senha_do_usuario"));
	}

}