Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
//License from project: Apache License 

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

public class Main {
    private final static String ALGORITHM = "DES";

    /**
     * Decrypt data
     * @param secretKey -   a secret key used for decryption
     * @param data      -   data to decrypt
     * @return   Decrypted data
     * @throws Exception
     */
    public static String decipher(String secretKey, String data) throws Exception {
        // Key has to be of length 8
        if (secretKey == null || secretKey.length() != 8)
            throw new Exception("Invalid key length - 8 bytes key needed!");

        SecretKey key = new SecretKeySpec(secretKey.getBytes(), ALGORITHM);
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, key);

        return new String(cipher.doFinal(toByte(data)));
    }

    private static byte[] toByte(String hexString) {
        int len = hexString.length() / 2;

        byte[] result = new byte[len];

        for (int i = 0; i < len; i++)
            result[i] = Integer.valueOf(hexString.substring(2 * i, 2 * i + 2), 16).byteValue();
        return result;
    }
}