AESCBCDecryption.java

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

public class AESCBCDecryption {
    
    static final String cipher_type = "AES/CBC/PKCS5Padding";

    public static void main(String[] args) {
        String key = "57067125438768260656188878670043";
        String iv = "5706712543876826";
        String data = "dd3364461dbca39ddb5eb32e9f11b81f000acac9ce8b91369f8bf7e4a88787785a8cc498c85ea20370e68f0e7014e92a2" +
                "b5aedd4c670ec172d7adb45dfa5a770b582e8ed255bb857d94afdfd6e579525f24890070f984b8862133eda9cbb118ba7880db125c32dea7e7c54bc77abfc02";

        byte[] enc = decodeHexString(data);
        byte[] dec = decode(key, iv, enc);
        byte[] dec2= decode(key, iv, decodeHexString(new String(dec)));

        System.out.println(new String(dec2));
    }

    public static byte[] decode(String skey, String iv, byte[] data) {
        return process(Cipher.DECRYPT_MODE, skey, iv, data);
    }

    private static byte[] process(int mode, String skey, String iv, byte[] data) {
        SecretKeySpec key = new SecretKeySpec(skey.getBytes(), "AES");
        IvParameterSpec param = new IvParameterSpec(iv.getBytes());
        try {
            Cipher cipher = Cipher.getInstance(cipher_type);
            cipher.init(mode, key, param);
            return cipher.doFinal(data);
        } catch (Exception e) {
            System.err.println(e.getMessage());
            throw new RuntimeException(e);
        }
    }

    public static byte[] decodeHexString(String hexString) {
        if(hexString.length() % 2 != 0){
            hexString = addLeadingZeros(hexString.length() + 1, hexString);
        }

        byte[] bytes = new byte[hexString.length() / 2];
        for (int i = 0; i < hexString.length(); i += 2) {
            bytes[i / 2] = hexToByte(hexString.substring(i, i + 2));
        }
        return bytes;
    }

    private static String addLeadingZeros(int count, String hexString) {
        StringBuilder sb = new StringBuilder();
        while (count-- > 0){
            sb.append('0');
        }
        sb.append(hexString);
        return sb.toString();
    }

    public static byte hexToByte(String hexString) {
        int firstDigit = toDigit(hexString.charAt(0));
        int secondDigit = toDigit(hexString.charAt(1));
        return (byte) ((firstDigit << 4) + secondDigit);
    }

    private static int toDigit(char hexChar) {
        int digit = Character.digit(hexChar, 16);
        if(digit == -1) {
            throw new IllegalArgumentException(
                    "Invalid Hexadecimal Character: "+ hexChar);
        }
        return digit;
    }
}