AES加密解密以及遇到的問題

因爲工做需求，須要對一個字符串進行加密與解密的操做，本身在網上查了一下，發現AES對稱加密算法很是符合個人需求。它的簡單思路就是事先設置一個祕鑰（好比放在配置文件中），而後根據這個祕鑰對字符串進行加密與解密。具體實現代碼以下：

import java.security.InvalidKeyException;
import java.security.Key;
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;
 
public class AESEncryptUtil {
    /**
     * 加密
     * @param encryptString  待加密內容 
     * @param password 解密密鑰 
     * @return
     */
    public static String encrypt(String encryptString,String passWord){
        String result =null;
        try {
            // 生成Key
            KeyGenerator keyGenerator;
            keyGenerator = KeyGenerator.getInstance("AES");
            // 使用這種初始化方法能夠特定種子來生成密鑰，這樣加密後的密文是惟一固定的。
            //keyGenerator.init(128, new SecureRandom(passWord.getBytes()));
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );
            secureRandom.setSeed(passWord.getBytes());
            keyGenerator.init(128,secureRandom);
            SecretKey secretKey = keyGenerator.generateKey();
            byte[] keyBytes = secretKey.getEncoded();
            // Key轉換
            Key key = new SecretKeySpec(keyBytes, "AES");
            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE, key);
            byte[] encodeResult = cipher.doFinal(encryptString.getBytes());
            result = parseByte2HexStr(encodeResult); ;
        } catch (InvalidKeyException e) {
              e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
              e.printStackTrace();
        } catch (BadPaddingException e) {
              e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        }
        return result;
    }
    
 
    /**
     * 解密
     * @param decryptString  待解密內容 
     * @param password 解密密鑰 
     * @return
     */
    public static String decrypt(String decryptString,String passWord){
        String result = null;
        try {
            byte[] decryptBytes = parseHexStr2Byte(decryptString);
            // 生成Key
            KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
            // 使用這種初始化方法能夠特定種子來生成密鑰，這樣加密後的密文是惟一固定的。
            //keyGenerator.init(128, new SecureRandom(passWord.getBytes()));
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );
            secureRandom.setSeed(passWord.getBytes());
            keyGenerator.init(128,secureRandom);
            SecretKey secretKey = keyGenerator.generateKey();
            byte[] keyBytes = secretKey.getEncoded();
            // Key轉換
            Key key = new SecretKeySpec(keyBytes, "AES");
            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
            cipher.init(Cipher.DECRYPT_MODE, key);
            byte[] decodeResult = cipher.doFinal(decryptBytes);
            result = new String(decodeResult);
        }catch(NumberFormatException e){
            e.printStackTrace();
            System.out.println("AES解密參數非法！");
            return "";
        } 
        catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } 
 
        return result;
    }
    
    /**將二進制轉換成16進制 
     * @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();  
    }  
    
    /**將16進制轉換爲二進制 
     * @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;  
    }  
}

 
 
     上述代碼中標註紅色的部分是我最初使用的版本，在本身本地的windows系統中是徹底沒有問題的，但當把項目部署到Linux服務器上時，在解密的過程當中出現錯誤：javax.crypto.BadPaddingException: Given final block not properly padded
     在網上查找後，發現是在生成key的時候出現的問題，因而將程序中解密部分的紅色代碼改爲藍色代碼。最初覺得只有解密過程出現錯誤，因此就沒有修改加密過程的key值，所以錯誤依舊 ，花費很長時間才發現是加密沒有修改的緣由，細心很重要啊。
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