javax.crypto.BadPaddingException: Given final block not properly padded

在项目中运用到了Java的AES加密，本地Windows调试一切正常，部署到Linux服务器后一直报空指针异常。

经过一番调试，找到真正原因：javax.crypto.BadPaddingException: Given final block not properly padded

package com.daredo.utils;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.security.SecureRandom;

/**
 * Created by IntelliJ IDEA
 * Author: d-arlin@qq.com
 * Date: 2018/3/14
 * Time: 15:38
 */
public class SecurityUtils {

    /**
     * 编码格式
     */
    private static String ENCODING = "UTF-8";
    /**
     * 加密算法
     */
    public static final String KEY_ALGORITHM = "AES";

    /**
     * 加密
     *
     * @param content 待加密内容
     * @param key     加密的密钥
     * @return
     */
    public static String encrypt(String content, String key) {
        try {
            KeyGenerator kgen = KeyGenerator.getInstance(KEY_ALGORITHM);
            kgen.init(128, new SecureRandom(key.getBytes(ENCODING)));
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec secretKeySpec = new SecretKeySpec(enCodeFormat, KEY_ALGORITHM);
            Cipher cipher = Cipher.getInstance(KEY_ALGORITHM);
            byte[] byteContent = content.getBytes(ENCODING);
            cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
            byte[] byteRresult = cipher.doFinal(byteContent);
            StringBuffer sb = new StringBuffer();
            for (int i = 0; i < byteRresult.length; i++) {
                String hex = Integer.toHexString(byteRresult[i] & 0xFF);
                if (hex.length() == 1) hex = '0' + hex;
                sb.append(hex.toUpperCase());
            }
            return sb.toString();
        } catch (Exception e) {
            e.toString();
        }
        return null;
    }

    /**
     * 解密
     *
     * @param content 待解密内容
     * @param key     解密的密钥
     * @return
     */
    public static String decrypt(String content, String key) {
        if (content.length() < 1) return null;
        byte[] byteRresult = new byte[content.length() / 2];
        for (int i = 0; i < content.length() / 2; i++) {
            int high = Integer.parseInt(content.substring(i * 2, i * 2 + 1), 16);
            int low = Integer.parseInt(content.substring(i * 2 + 1, i * 2 + 2), 16);
            byteRresult[i] = (byte) (high * 16 + low);
        }
        try {
            KeyGenerator kgen = KeyGenerator.getInstance(KEY_ALGORITHM);
            kgen.init(128, new SecureRandom(key.getBytes(ENCODING)));
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec secretKeySpec = new SecretKeySpec(enCodeFormat, KEY_ALGORITHM);
            Cipher cipher = Cipher.getInstance(KEY_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
            byte[] result = cipher.doFinal(byteRresult);
            return new String(result, ENCODING);
        } catch (Exception e) {
            e.toString();
        }
        return null;
    }

}

那么为什么在Windows正常，在Linux就出现异常呢？

原因分析
SecureRandom 实现完全随操作系统本身的內部状态，除非调用方在调用 getInstance 方法之后又调用了 setSeed 方法；

该实现在 windows 上每次生成的 key 都相同，但是在 solaris 或部分 linux 系统上则不同。

解决方法

package com.daredo.utils;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.security.SecureRandom;

/**
 * Created by IntelliJ IDEA
 * Author: d-arlin@qq.com
 * Date: 2018/3/14
 * Time: 15:38
 */
public class SecurityUtils {

    /**
     * 编码格式
     */
    private static final String ENCODING = "UTF-8";
    /**
     * 加密算法
     */
    public static final String KEY_ALGORITHM = "AES";
    /**
     * 签名算法
     */
    public static final String SIGN_ALGORITHMS = "SHA1PRNG";

    /**
     * 加密
     *
     * @param content 待加密内容
     * @param key     加密的密钥
     * @return
     */
    public static String encrypt(String content, String key) {
        try {
            KeyGenerator kgen = KeyGenerator.getInstance(KEY_ALGORITHM);
            SecureRandom random = SecureRandom.getInstance(SIGN_ALGORITHMS);
            random.setSeed(key.getBytes(ENCODING));
            kgen.init(128, random);
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec secretKeySpec = new SecretKeySpec(enCodeFormat, KEY_ALGORITHM);
            Cipher cipher = Cipher.getInstance(KEY_ALGORITHM);
            byte[] byteContent = content.getBytes(ENCODING);
            cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
            byte[] byteRresult = cipher.doFinal(byteContent);
            StringBuffer sb = new StringBuffer();
            for (int i = 0; i < byteRresult.length; i++) {
                String hex = Integer.toHexString(byteRresult[i] & 0xFF);
                if (hex.length() == 1) hex = '0' + hex;
                sb.append(hex.toUpperCase());
            }
            return sb.toString();
        } catch (Exception e) {
            e.toString();
        }
        return null;
    }

    /**
     * 解密
     *
     * @param content 待解密内容
     * @param key     解密的密钥
     * @return
     */
    public static String decrypt(String content, String key) {
        if (content.length() < 1) return null;
        byte[] byteRresult = new byte[content.length() / 2];
        for (int i = 0; i < content.length() / 2; i++) {
            int high = Integer.parseInt(content.substring(i * 2, i * 2 + 1), 16);
            int low = Integer.parseInt(content.substring(i * 2 + 1, i * 2 + 2), 16);
            byteRresult[i] = (byte) (high * 16 + low);
        }
        try {
            KeyGenerator kgen = KeyGenerator.getInstance(KEY_ALGORITHM);
            SecureRandom random = SecureRandom.getInstance(SIGN_ALGORITHMS);
            random.setSeed(key.getBytes(ENCODING));
            kgen.init(128, random);
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec secretKeySpec = new SecretKeySpec(enCodeFormat, KEY_ALGORITHM);
            Cipher cipher = Cipher.getInstance(KEY_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
            byte[] result = cipher.doFinal(byteRresult);
            return new String(result, ENCODING);
        } catch (Exception e) {
            e.toString();
        }
        return null;
    }
}