Java 实现 AES 加解密

　　毕业课题中需要使用加解密算法，要求加解密前后的数据长度不会变化，查了一些资料，发现可以采用AES加密的CFB跟OFB模式是无填充的模式，可以保持加解密前后数据的长度相等。下面上代码：

import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;


public class Encrypt_Decrypt_AES {


    /**
     * AES加密算法，调用Java自有类库，采用CFB模式密文反馈无填充模式，可以保证数据长度在加密前后是相同的
     * @param content 待加密内容
     * @param key 密钥
     * @return byte[] 加密结果用byte数组表示
     * 
     */
    public static byte[] encrypt_AES(String content, String key) {
        try {
            Cipher aesECB = Cipher.getInstance("AES/CFB/NoPadding");
            SecretKeySpec keySpec = new SecretKeySpec(key.getBytes(), "AES");
            IvParameterSpec ivSpec = new IvParameterSpec(key.getBytes());
            aesECB.init(Cipher.ENCRYPT_MODE, keySpec, ivSpec);
            byte[] result = aesECB.doFinal(content.getBytes());
            return result;
        } 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();
        } catch (InvalidAlgorithmParameterException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
        return null;
    }
    
    /**
     * 
     * @param content 待解密内容，字符串形式
     * @param key    解密用的密钥
     * @return    使用字符串形式返回解密内容
     * @throws UnsupportedEncodingException
     */
    
    public static String decrypt_AES(byte[] content, String key) throws UnsupportedEncodingException {
        try {
            Cipher aesECB = Cipher.getInstance("AES/CFB/NoPadding");
            SecretKeySpec keySpec = new SecretKeySpec(key.getBytes(), "AES");
            IvParameterSpec ivSpec = new IvParameterSpec(key.getBytes());
            aesECB.init(Cipher.DECRYPT_MODE, keySpec, ivSpec);
            byte[] result = aesECB.doFinal(content);
            String AES_decode=new String(result,"utf-8");
            /************************************/
//            System.out.println("解密结果："+AES_decode);
            return AES_decode;
        } 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();
        } catch (InvalidAlgorithmParameterException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
        return null;
    }



    public static void main(String[] str) throws InvalidKeyException,
            InvalidAlgorithmParameterException, IllegalBlockSizeException,
            BadPaddingException, UnsupportedEncodingException {

        
        String s = "fire fox 22";
        byte[] r = encrypt_AES(s, "@93456781234567A");
        for (byte i : r){
            String l = Integer.toBinaryString((i & 0xFF) + 0x100).substring(1);  
            System.out.print(l+" ");
        }
        System.out.println();
        decrypt_AES(r, "@93456781234567A");
    }


}