java使⽤AES-128-cbc加解密
⾸先介绍相关的⼏个重要的类：
（⼀）KeyGenerator
Java提供了⼀个名称为KeyGenerator的类，该类⽤于⽣成密钥，此类的对象是可重⽤的。
要使⽤KeyGenerator类⽣成密钥，请按照以下步骤操作
第1步：创建KeyGenerator对象
KeyGenerator类提供getInstance()⽅法，该⽅法接受表⽰所需密钥⽣成算法的String变量，并返回⽣成密钥的KeyGenerator对象。
第2步：创建SecureRandom对象java.Security包的SecureRandom类提供了⼀个强⼤的随机数⽣成器，⽤于在Java中⽣成随机数
第3步：第初始化KeyGeneratorKeyGenerator类提供了⼀个名为init()的⽅法，此⽅法接受SecureRandom对象并初始化当前的KeyGenerator。
第4步：利⽤ateKey() ⽣成⼀个密钥。返回的是⼀个SecretKey ,SecretKey key = ateKey()
第5步：得到密钥的字节数组,byte[] keys = Encoded();
private static void createKey(){
try{
KeyGenerator keyGenerator = Instance("AES");
keyGenerator.init(128,new SecureRandom());
SecretKey secretKey = ateKey();
key = Encoded();
}catch(NoSuchAlgorithmException e){
e.printStackTrace();
}
}
也可以使⽤SecretKeySpec 类创造密钥：
SecretKeySpec keySpec =new Bytes(StandardCharsets.UTF_8),"AES");
（⼆）Cipher
此类为加密和解密提供密码功能。
（1）为创建 Cipher 对象，应⽤程序调⽤ Cipher 的 getInstance ⽅法并将所请求转换 的名称传递给它。
（2）初始化cipher.init(字段，密钥，new Bytes()) ) ，最后⼀个参数为初始化向量，并且string为16字节(三)CipherInputStream
读取字节流时调⽤的cipher.update()⽅法进⾏流部分加密， 当加密到最后⼀段时，会调⽤ doFinal() ⽅法。
CipherInputStream cipherInputStream =new CipherInputStream(inputFile, cipher);
加密代码：
/*
*加密
*/
private static void encodeFile(String path, String encodePath)throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidAlgorithmParameter Exception, InvalidKeyException, IOException {
SecretKeySpec keySpec =new SecretKeySpec(key,"AES");
Cipher cipher = Instance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE,keySpec,new Bytes(StandardCharsets.UTF_8)));
FileInputStream inputStream =new FileInputStream(path);
CipherInputStream cipherInputStream =new CipherInputStream(inputStream,cipher);
FileOutputStream outputStream =new FileOutputStream(encodePath);
int length;
byte[] b =new byte[1024];
while((length = ad(b))!=-1){
outputStream.write(b);
outputStream.flush();
}
cipherInputStream.close();
outputStream.close();
}
解密：
/*
* 解密
*/
private static void decoder(String encode,String decoder)throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidAlgorithmParameterExce ption, InvalidKeyException, IOException {
SecretKeySpec keySpec =new SecretKeySpec(key,"AES");
Cipher cipher = Instance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE,keySpec,new Bytes(StandardCharsets.UTF_8)));
java生成随机数的方法FileInputStream inputStream =new FileInputStream(encode);
FileOutputStream outputStream =new FileOutputStream(decoder);
CipherOutputStream cipherOutputStream =new CipherOutputStream(outputStream,cipher);
int length;
byte[] bytes =new byte[1024];
while((length = ad(bytes))!=-1){
cipherOutputStream.write(bytes,0,length);
}
inputStream.close();
cipherOutputStream.close();
}
完整⽰例代码：（对⽂件进⾏加解密）
public class MyClass {
private static byte[] key;
private static String IV ="ikldokiujujikijo";
public static void main(String[] args){
createKey();
try{
encodeFile("C:\\Users\\zhaol\\Desktop\\SerurityUtil.java","C:\\Users\\zhaol\\Desktop\\1.java");
decoder("C:\\Users\\zhaol\\Desktop\\1.java","C:\\Users\\zhaol\\Desktop\\2.java");
}catch(NoSuchPaddingException e){
e.printStackTrace();
}catch(NoSuchAlgorithmException e){
e.printStackTrace();
}catch(InvalidAlgorithmParameterException e){
e.printStackTrace();
}catch(InvalidKeyException e){
e.printStackTrace();
}catch(IOException e){
}catch(IOException e){
e.printStackTrace();
}
}
private static void createKey(){
try{
KeyGenerator keyGenerator = Instance("AES");
keyGenerator.init(128,new SecureRandom());
SecretKey secretKey = ateKey();
key = Encoded();
}catch(NoSuchAlgorithmException e){
e.printStackTrace();
}
}
/*
*加密
*/
private static void encodeFile(String path, String encodePath)throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidAlgorithmParameter Exception, InvalidKeyException, IOException {
SecretKeySpec keySpec =new SecretKeySpec(key,"AES");
Cipher cipher = Instance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE,keySpec,new Bytes(StandardCharsets.UTF_8)));
FileInputStream inputStream =new FileInputStream(path);
CipherInputStream cipherInputStream =new CipherInputStream(inputStream,cipher);
FileOutputStream outputStream =new FileOutputStream(encodePath);
int length;
byte[] b =new byte[1024];
while((length = ad(b))!=-1){
outputStream.write(b,0,length);
outputStream.flush();
}
cipherInputStream.close();
outputStream.close();
}
/*
* 解密
*/
private static void decoder(String encode,String decoder)throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidAlgorithmParameterExce ption, InvalidKeyException, IOException {
SecretKeySpec keySpec =new SecretKeySpec(key,"AES");
Cipher cipher = Instance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE,keySpec,new Bytes(StandardCharsets.UTF_8)));
FileInputStream inputStream =new FileInputStream(encode);
FileOutputStream outputStream =new FileOutputStream(decoder);
CipherOutputStream cipherOutputStream =new CipherOutputStream(outputStream,cipher);
int length;
byte[] bytes =new byte[1024];
while((length = ad(bytes))!=-1){
cipherOutputStream.write(bytes,0,length);
}
inputStream.close();
cipherOutputStream.close();
}
}

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