AES CBC 加密解密，带偏移量

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;

public class AesEncodeUtil {

//偏移量
public static final String VIPARA = "xxx";   //AES 为16bytes. DES 为8bytes

//编码方式
public static final String CODE_TYPE = "UTF-8";

// public static final String CODE_TYPE = “GBK”;

//填充类型
public static final String AES_TYPE = "AES/CBC/PKCS5Padding";
//public static final String AES_TYPE = "AES/ECB/PKCS7Padding";
//此类型 加密内容,密钥必须为16字节的倍数位,否则抛异常,需要字节补全再进行加密

// public static final String AES_TYPE = “AES/ECB/NoPadding”;
//java 不支持ZeroPadding
//public static final String AES_TYPE = “AES/CBC/ZeroPadding”;

//私钥
private static final String AES_KEY="xxx";   //AES固定格式为128/192/256 bits.即：16/24/32bytes。DES固定格式为128bits，即8bytes。

//字符补全
private static final String[] consult = new String[]{"0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F","G"};


/**
 * 加密
 *
 * @param cleartext
 * @return
 */
public static String encrypt(String cleartext) {
    //加密方式： AES128(CBC/PKCS5Padding) + Base64, 私钥：1111222233334444
    try {
        IvParameterSpec zeroIv = new IvParameterSpec(VIPARA.getBytes());
        //两个参数，第一个为私钥字节数组， 第二个为加密方式 AES或者DES
        SecretKeySpec key = new SecretKeySpec(AES_KEY.getBytes(), "AES");
        //实例化加密类，参数为加密方式，要写全
        Cipher cipher = Cipher.getInstance(AES_TYPE); //PKCS5Padding比PKCS7Padding效率高，PKCS7Padding可支持IOS加解密
        //初始化，此方法可以采用三种方式，按加密算法要求来添加。（1）无第三个参数（2）第三个参数为SecureRandom random = new SecureRandom();中random对象，随机数。(AES不可采用这种方法)（3）采用此代码中的IVParameterSpec
        //加密时使用:ENCRYPT_MODE;  解密时使用:DECRYPT_MODE;
        cipher.init(Cipher.ENCRYPT_MODE, key,zeroIv); //CBC类型的可以在第三个参数传递偏移量zeroIv,ECB没有偏移量
        //加密操作,返回加密后的字节数组，然后需要编码。主要编解码方式有Base64, HEX, UUE,7bit等等。此处看服务器需要什么编码方式
        byte[] encryptedData = cipher.doFinal(cleartext.getBytes(CODE_TYPE));

        return new BASE64Encoder().encode(encryptedData);
    } catch (Exception e) {
        e.printStackTrace();
        return "";
    }
}

/**
 * 解密
 *
 * @param encrypted
 * @return
 */
public static String decrypt(String encrypted) {
    try {
        byte[] byteMi = new BASE64Decoder().decodeBuffer(encrypted);
        IvParameterSpec zeroIv = new IvParameterSpec(VIPARA.getBytes());
        SecretKeySpec key = new SecretKeySpec(
                AES_KEY.getBytes(), "AES");
        Cipher cipher = Cipher.getInstance(AES_TYPE);
        //与加密时不同MODE:Cipher.DECRYPT_MODE
        cipher.init(Cipher.DECRYPT_MODE, key,zeroIv);  //CBC类型的可以在第三个参数传递偏移量zeroIv,ECB没有偏移量
        byte[] decryptedData = cipher.doFinal(byteMi);
        return new String(decryptedData, CODE_TYPE);
    } catch (Exception e) {
        e.printStackTrace();
        return "";
    }
}

/**
 * 测试
 *
 * @param args
 * @throws Exception
 */
public static void main(String[] args) throws Exception {
    String content = "xxx";
    test(content);
}

public static void test(String content) throws UnsupportedEncodingException{
    System.out.println("加密内容：" + content);
    //字节数
    int num = content.getBytes(CODE_TYPE).length;
    System.out.println("加密内容字节数: " + num);
    System.out.println("加密内容是否16倍数: " + (num%16 == 0 ? true : false));

    //字节补全
    if(AES_TYPE.equals("AES/ECB/NoPadding")){
        System.out.println();
        content = completionCodeFor16Bytes(content);
        System.out.println("加密内容补全后: "+content);
    }

    System.out.println();

    // 加密
    String encryptResult = encrypt(content);
    content = new String(encryptResult);
    System.out.println("加密后：" + content);

    System.out.println();

    // 解密
    String decryptResult = decrypt(encryptResult);
    content = new String(decryptResult);
    //还原
    if(AES_TYPE.equals("AES/ECB/NoPadding")){
        System.out.println("解密内容还原前: "+content);
        content = resumeCodeOf16Bytes(content);
    }

    System.out.println("解密完成后：" + content);
}




//NoPadding
//补全字符
public static String completionCodeFor16Bytes(String str) throws UnsupportedEncodingException{
    int num = str.getBytes(CODE_TYPE).length;
    int index = num%16;
    //进行加密内容补全操作, 加密内容应该为 16字节的倍数, 当不足16*n字节是进行补全, 差一位时 补全16+1位
    //补全字符 以 $ 开始,$后一位代表$后补全字符位数,之后全部以0进行补全;
    if(index != 0){
        StringBuffer sbBuffer = new StringBuffer(str);
        if(16-index == 1){
            sbBuffer.append("$" + consult[16-1] + addStr(16-1-1));
        }else{
            sbBuffer.append("$" + consult[16-index-1] + addStr(16-index-1-1));
        }
        str = sbBuffer.toString();
    }
    return str;
}

//追加字符
public static String addStr(int num){
    StringBuffer sbBuffer = new StringBuffer("");
    for (int i = 0; i < num; i++) {
        sbBuffer.append("0");
    }
    return sbBuffer.toString();
}


//还原字符(进行字符判断)
public static String resumeCodeOf16Bytes(String str){
    int indexOf = str.lastIndexOf("$");

// System.out.println(indexOf);
if(indexOf == -1){
return str;
}
String trim = str.substring(indexOf+1,indexOf+2).trim();
// System.out.println(trim);
int num = 0;
for (int i = 0; i < consult.length; i++) {
if(trim.equals(consult[i])){
num = i;
}
}
if(num == 0){
return str;
}
return str.substring(0,indexOf).trim();
}

}