javax.crypto.IllegalBlockSizeException: Input length must be multiple of 16 when decrypting with pad

原文地址：http://songjianyong.iteye.com/blog/1571029

/** * AESHelper.java * cn.com.songjy.test * * Function： TODO  * *   ver     date              author * ────────────────────────────────── *            2012-6-29         songjianyong * * Copyright (c) 2012, TNT All Rights Reserved.*/package cn.com.songjy.test;import java.io.UnsupportedEncodingException;import java.security.InvalidKeyException;import java.security.NoSuchAlgorithmException;import java.security.SecureRandom;import javax.crypto.BadPaddingException;import javax.crypto.Cipher;import javax.crypto.IllegalBlockSizeException;import javax.crypto.KeyGenerator;import javax.crypto.NoSuchPaddingException;import javax.crypto.SecretKey;import javax.crypto.spec.SecretKeySpec;/** * ClassName:AESHelper * * @author   songjianyong * @version  1.0 * @since    v1.0 * @Date     2012-6-29 下午2:06:07  */public class AESHelper {    /**     * @method main     * @param args     * @throws      * @since v1.0     */    public static void main(String[] args) {        String content = "宋建勇";        String password = "12345678";        byte[] encryptResult = encrypt(content, password);//加密        byte[] decryptResult = decrypt(encryptResult,password);//解密        System.out.println("解密后：" + new String(decryptResult));                /*容易出错的地方，请看下面代码*/        System.out.println("***********************************************");        try {            String encryptResultStr = new String(encryptResult,"utf-8");            decryptResult = decrypt(encryptResultStr.getBytes("utf-8"),password);            System.out.println("解密后：" + new String(decryptResult));        } catch (UnsupportedEncodingException e) {            e.printStackTrace();        } catch (Exception e) {            // TODO: handle exception        }        /*则，系统会报出如下异常：javax.crypto.IllegalBlockSizeException: Input length must be multiple of 16 when decrypting with padded cipher    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)    at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)    at javax.crypto.Cipher.doFinal(DashoA13*..)    at cn.com.songjy.test.ASCHelper.decrypt(ASCHelper.java:131)    at cn.com.songjy.test.ASCHelper.main(ASCHelper.java:58)         * */        /*这主要是因为加密后的byte数组是不能强制转换成字符串的, 换言之,字符串和byte数组在这种情况下不是互逆的,         * 要避免这种情况，我们需要做一些修订，可以考虑将二进制数据转换成十六进制表示,         * 主要有两个方法:将二进制转换成16进制(见方法parseByte2HexStr)或是将16进制转换为二进制(见方法parseHexStr2Byte)*/                /*然后，我们再修订以上测试代码*/        System.out.println("***********************************************");        String encryptResultStr = parseByte2HexStr(encryptResult);        System.out.println("加密后：" + encryptResultStr);        byte[] decryptFrom = parseHexStr2Byte(encryptResultStr);        decryptResult = decrypt(decryptFrom,password);//解码        System.out.println("解密后：" + new String(decryptResult));    }    /**     * 加密     * @method encrypt     * @param content    需要加密的内容     * @param password    加密密码     * @return     * @throws      * @since v1.0     */    public static byte[] encrypt(String content, String password){        try {            KeyGenerator kgen = KeyGenerator.getInstance("AES");            kgen.init(128, new SecureRandom(password.getBytes()));            SecretKey secretKey = kgen.generateKey();            byte[] enCodeFormat = secretKey.getEncoded();            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");            Cipher cipher = Cipher.getInstance("AES");// 创建密码器            byte[] byteContent = content.getBytes("utf-8");            cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化            byte[] result = cipher.doFinal(byteContent);            return result; // 加密        } catch (NoSuchAlgorithmException e) {            e.printStackTrace();        }catch (NoSuchPaddingException e) {            e.printStackTrace();        }catch (UnsupportedEncodingException e) {            e.printStackTrace();        }catch (InvalidKeyException e) {            e.printStackTrace();        }catch (IllegalBlockSizeException e) {            e.printStackTrace();        }catch (BadPaddingException e) {            e.printStackTrace();        }        return null;    }        /**     * 解密     * @method decrypt     * @param content    待解密内容     * @param password    解密密钥     * @return     * @throws      * @since v1.0     */    public static byte[] decrypt(byte[] content, String password){        try {            KeyGenerator kgen = KeyGenerator.getInstance("AES");            kgen.init(128, new SecureRandom(password.getBytes()));            SecretKey secretKey = kgen.generateKey();            byte[] enCodeFormat = secretKey.getEncoded();            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");            Cipher cipher = Cipher.getInstance("AES");// 创建密码器            cipher.init(Cipher.DECRYPT_MODE, key);// 初始化            byte[] result = cipher.doFinal(content);            return result; // 解密        } catch (NoSuchAlgorithmException e) {            e.printStackTrace();        }catch (NoSuchPaddingException e) {            e.printStackTrace();        }catch (InvalidKeyException e) {            e.printStackTrace();        }catch (IllegalBlockSizeException e) {            e.printStackTrace();        }catch (BadPaddingException e) {            e.printStackTrace();        }                return null;    }        /**     * 将二进制转换成16进制     * @method parseByte2HexStr     * @param buf     * @return     * @throws      * @since v1.0     */    public static String parseByte2HexStr(byte buf[]){        StringBuffer sb = new StringBuffer();        for(int i = 0; i < buf.length; i++){            String hex = Integer.toHexString(buf[i] & 0xFF);            if (hex.length() == 1) {                hex = '0' + hex;            }            sb.append(hex.toUpperCase());        }        return sb.toString();    }        /**     * 将16进制转换为二进制     * @method parseHexStr2Byte     * @param hexStr     * @return     * @throws      * @since v1.0     */    public static byte[] parseHexStr2Byte(String hexStr){        if(hexStr.length() < 1)            return null;        byte[] result = new byte[hexStr.length()/2];        for (int i = 0;i< hexStr.length()/2; i++) {            int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);            int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);            result[i] = (byte) (high * 16 + low);        }        return result;    }        /**     * 另外一种加密方式--这种加密方式有两种限制     * 1、密钥必须是16位的     * 2、待加密内容的长度必须是16的倍数，如果不是16的倍数，就会出如下异常     * javax.crypto.IllegalBlockSizeException: Input length not multiple of 16 bytes        at com.sun.crypto.provider.SunJCE_f.a(DashoA13*..)        at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)        at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)        at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)        at javax.crypto.Cipher.doFinal(DashoA13*..)        要解决如上异常，可以通过补全传入加密内容等方式进行避免。     * @method encrypt2     * @param content    需要加密的内容     * @param password    加密密码     * @return     * @throws      * @since v1.0     */    public static byte[] encrypt2(String content, String password){        try {            SecretKeySpec key = new SecretKeySpec(password.getBytes(), "AES");            Cipher cipher = Cipher.getInstance("AES/ECB/NoPadding");            byte[] byteContent = content.getBytes("utf-8");            cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化            byte[] result = cipher.doFinal(byteContent);            return result; // 加密        } catch (NoSuchAlgorithmException e) {            e.printStackTrace();        } catch (NoSuchPaddingException e) {            e.printStackTrace();        } catch (UnsupportedEncodingException e) {            e.printStackTrace();        } catch (InvalidKeyException e) {            e.printStackTrace();        } catch (IllegalBlockSizeException e) {            e.printStackTrace();        } catch (BadPaddingException e) {            e.printStackTrace();        }        return null;    }        }

测试效果： 

解密后：宋建勇 
*********************************************** 
javax.crypto.IllegalBlockSizeException: Input length must be multiple of 16 when decrypting with padded cipher
at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..) 
at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..) 
at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..) 
at javax.crypto.Cipher.doFinal(DashoA13*..) 
at cn.com.songjy.test.ASCHelper.decrypt(ASCHelper.java:141) 
at cn.com.songjy.test.ASCHelper.main(ASCHelper.java:58) 
java.lang.NullPointerException 
at java.lang.String.<init>(String.java:594) 
at cn.com.songjy.test.ASCHelper.main(ASCHelper.java:59) 
*********************************************** 
加密后：961000B09BDDA1F81E81EF3EFDC3A926 
解密后：宋建勇