Encrypt and decrypt string by java

Encrypt and decrypt string by java

This task use java to encrypt and decrypt string.

Encrypt and decrypt string using AES

1. Create Crypto.java as following
2. Call encrypt and decrypt methods as following

Call methods

---

try {
    String key = UUID.randomUUID().toString().replaceAll("-", "");
    String src = "Hello world!";
    String tag1 = Crypto.encrypt(src, key);
    String tag2 = Crypto.decrypt(tag1, key);
    logger.info(src);
    logger.info(tag1);
    logger.info(tag2);
} catch (Exception e) {
    logger.error("", e);
}
    

Crypto.java

---

public class Crypto {

    public static String encrypt(String value, String key) throws GeneralSecurityException {
        SecretKeySpec sks = new SecretKeySpec(hexStringToByteArray(key), "AES");
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.ENCRYPT_MODE, sks, cipher.getParameters());
        byte[] encrypted = cipher.doFinal(value.getBytes());
        return byteArrayToHexString(encrypted);
    }

    public static String decrypt(String message, String key) throws GeneralSecurityException {
        SecretKeySpec sks = new SecretKeySpec(hexStringToByteArray(key), "AES");
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.DECRYPT_MODE, sks);
        byte[] decrypted = cipher.doFinal(hexStringToByteArray(message));
        return new String(decrypted);
    }   
    
    private static String byteArrayToHexString(byte[] b){
        StringBuffer sb = new StringBuffer(b.length * 2);
        for (int i = 0; i < b.length; i++){
            int v = b[i] & 0xff;
            if (v < 16) {
                sb.append('0');
            }
            sb.append(Integer.toHexString(v));
        }
        return sb.toString().toUpperCase();
    }
   
    private static byte[] hexStringToByteArray(String s) {
        byte[] b = new byte[s.length() / 2];
        for (int i = 0; i < b.length; i++){
            int index = i * 2;
            int v = Integer.parseInt(s.substring(index, index + 2), 16);
            b[i] = (byte)v;
        }
        return b;
    }
     
}
    

Java