A util that comes in handy when you want to encrypt any text and latter on decrypt it. Symmetric encryption.

fuzzy.java

package com.rickmune.sample.api.security.fuzzy;


import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class SecThing {
    private static final String ENCODING = "UTF-8";
    private static final String CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
    private static final SecureRandom rnd = new SecureRandom();

    public static String encrypt(String cleanKey, String message) throws Exception {
        if (message == null || message.isEmpty()) {
            throw new Exception("decrypt message cannot be empty");
        } else if( cleanKey == null || cleanKey.isEmpty() ){
            throw new Exception("decrypt Key cannot be empty");
        }
        String payload = null;
        try {
            byte[] randomBytes = initVectorGenerator(16).getBytes();
            IvParameterSpec iv = new IvParameterSpec(randomBytes);
            SecretKeySpec secretKeySpec = new SecretKeySpec(cleanKey.getBytes(), "AES");
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, iv);
            String messageB64 = Base64.encodeBytes(message.getBytes(ENCODING));
            byte[] encrypted = cipher.doFinal(messageB64.getBytes(ENCODING));
            payload = Base64.encodeBytes(encrypted) + new String(randomBytes, ENCODING);
        } catch (Exception e) {
            throw new EchoEncryptionException(e.getMessage());
        }

        return payload;
    }

    public static String decrypt(String key, String cleanMessage) throws Exception {
        if (cleanMessage == null || cleanMessage.isEmpty()) {
            throw new Exception("decrypt message cannot be empty");
        } else if( key == null || key.isEmpty() ){
            throw new Exception("decrypt Key cannot be empty");
        }
        String originalMessage = null;
        try {
            byte[] cleanKey = Base64.decode(key);
            SecretKeySpec secretKeySpec = new SecretKeySpec(cleanKey, "AES");
            byte[] encryptedPayload = Base64.decode(cleanMessage);
            //String randomString = ;Find a way to get this from the other party
            byte[] randomBytes = randomString.getBytes(ENCODING);
            IvParameterSpec iv = new IvParameterSpec(randomBytes);
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, iv);
            byte[] data = cipher.doFinal(encryptedPayload);
            byte[] originalMessageB64 = Base64.decode(new String(data, ENCODING));
            originalMessage = new String(originalMessageB64, ENCODING);
        } catch (Exception e) {
            throw new EchoEncryptionException(e.getMessage());
        }

        return originalMessage;
    }

    public static String initVectorGenerator(int length) {
        if (length < 1) throw new IllegalArgumentException("Length must be greater than 0");
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < length; i++) {
            sb.append(CHARSET.charAt(rnd.nextInt(CHARSET.length())));
        }
        return sb.toString();
    }
}