解决Linux操作系统下AES解密失败的问题

来源：互联网发布：工商银行数据中心编辑：程序博客网时间：2024/05/17 18:13

现象描述：

windows上加解密正常，linux上加密正常，解密时发生如下异常：

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

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 chb.test.crypto.AESUtils.crypt(AESUtils.java:386)
at chb.test.crypto.AESUtils.AesDecrypt(AESUtils.java:254)
at chb.test.crypto.AESUtils.main(AESUtils.java:40)

解决方法：

经过检查之后，定位在生成KEY的方法上，如下：

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public static SecretKey getKey (String strKey) {
try {
KeyGenerator _generator = KeyGenerator.getInstance( "AES" );
_generator.init(128, new SecureRandom(strKey.getBytes()));
return _generator.generateKey();
} catch (Exception e) {
throw new RuntimeException( " 初始化密钥出现异常 " );
}
}

修改到如下方式，问题解决：

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public static SecretKey getKey(String strKey) {
try {
KeyGenerator _generator = KeyGenerator.getInstance( "AES" );
SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );
secureRandom.setSeed(strKey.getBytes());
_generator.init(128,secureRandom);
return _generator.generateKey();
} catch (Exception e) {
throw new RuntimeException( " 初始化密钥出现异常 " );
}
}

原因分析

SecureRandom 实现完全隨操作系统本身的內部狀態，除非調用方在調用 getInstance 方法之後又調用了 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。

原因二：

1、加密完byte[] 后，需要将加密了的byte[] 转换成base64保存，如：
BASE64Encoder base64encoder = new BASE64Encoder();
String encode=base64encoder.encode(bytes)；

2、解密前，需要将加密后的字符串从base64转回来再解密，如：
BASE64Decoder base64decoder = new BASE64Decoder();
byte[] encodeByte = base64decoder.decodeBuffer(str);

完整例子：

Java代码

import java.io.IOException;
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;

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

public class SecurityAES {
    private final static String encoding = "UTF-8";
    /**
     * AES加密
     *
     * @param content
     * @param password
     * @return
     */
    public static String encryptAES(String content, String password) {
        byte[] encryptResult = encrypt(content, password);
        String encryptResultStr = parseByte2HexStr(encryptResult);
        // BASE64位加密
        encryptResultStr = ebotongEncrypto(encryptResultStr);
        return encryptResultStr;
    }

    /**
     * AES解密
     *
     * @param encryptResultStr
     * @param password
     * @return
     */
    public static String decrypt(String encryptResultStr, String password) {
        // BASE64位解密
        String decrpt = ebotongDecrypto(encryptResultStr);
        byte[] decryptFrom = parseHexStr2Byte(decrpt);
        byte[] decryptResult = decrypt(decryptFrom, password);
        return new String(decryptResult);
    }

        /**
     * 加密字符串
     */
    public static String ebotongEncrypto(String str) {
        BASE64Encoder base64encoder = new BASE64Encoder();
        String result = str;
        if (str != null && str.length() > 0) {
            try {
                byte[] encodeByte = str.getBytes(encoding);
                result = base64encoder.encode(encodeByte);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        //base64加密超过一定长度会自动换行需要去除换行符
        return result.replaceAll("\r\n", "").replaceAll("\r", "").replaceAll("\n", "");
    }

    /**
     * 解密字符串
     */
    public static String ebotongDecrypto(String str) {
        BASE64Decoder base64decoder = new BASE64Decoder();
        try {
            byte[] encodeByte = base64decoder.decodeBuffer(str);
            return new String(encodeByte);
        } catch (IOException e) {
            e.printStackTrace();
            return str;
        }
    }
    /**
     * 加密
     *
     * @param content 需要加密的内容
     * @param password 加密密码
     * @return
     */
    private static byte[] encrypt(String content, String password) {
            try {
                    KeyGenerator kgen = KeyGenerator.getInstance("AES");
                    //防止linux下随机生成key
                    SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );
                    secureRandom.setSeed(password.getBytes());
                    kgen.init(128, secureRandom);
                    //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 (InvalidKeyException e) {
                    e.printStackTrace();
            } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
            } catch (IllegalBlockSizeException e) {
                    e.printStackTrace();
            } catch (BadPaddingException e) {
                    e.printStackTrace();
            }
            return null;
    }

    /**解密
     * @param content 待解密内容
     * @param password 解密密钥
     * @return
     */
    private static byte[] decrypt(byte[] content, String password) {
            try {
                     KeyGenerator kgen = KeyGenerator.getInstance("AES");
                   //防止linux下随机生成key
                     SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );
                     secureRandom.setSeed(password.getBytes());
                     kgen.init(128, secureRandom);
                     //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; // 加密
            } 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
     * @param buf
     * @return
     */
    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
     * @param hexStr
     * @return
     */
    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;
    }

}