CryptoHelper.java

import java.security.MessageDigest; 
import java.security.NoSuchAlgorithmException; 
import java.nio.charset.StandardCharsets; 
public class CryptoHelper { 
  public static String sha256(String text) throws NoSuchAlgorithmException { 
    MessageDigest digest = MessageDigest.getInstance("SHA-256"); 
    digest.update(text.getBytes(StandardCharsets.UTF_8)); 
    byte[] hash = digest.digest(); 
    StringBuffer sb = new StringBuffer(); 
    for (int i = 0; i < hash.length; i++) 
      sb.append(Integer.toString((hash[i] & 0xff) + 0x100, 16).substring(1)); 
    return sb.toString().toUpperCase(); 
  }
}