// 未分类
DES加密的java使用
发布 2018-09-30 · 永久链接
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## 加密
``` java
public byte[] encrypt(byte[] data, String key) throws Exception {
try{
SecureRandom random = new SecureRandom();
DESKeySpec desKey = new DESKeySpec(key.getBytes());
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
SecretKey securekey = keyFactory.generateSecret(desKey);
Cipher cipher = Cipher.getInstance("DES");
cipher.init(Cipher.ENCRYPT_MODE, securekey, random);
return cipher.doFinal(data);
}catch(Throwable e){
e.printStackTrace();
}
return null;
}
```
`Cipher` 是真正加密的.
`key` 的长度应该是8，太长会截断，不够长会抛异常。
## 解密
``` java
public byte[] decrypt(byte[] data, String key) throws Exception {
SecureRandom random = new SecureRandom();
DESKeySpec desKey = new DESKeySpec(key.getBytes());
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
SecretKey securekey = keyFactory.generateSecret(desKey);
Cipher cipher = Cipher.getInstance("DES");
cipher.init(Cipher.DECRYPT_MODE, securekey, random);
return cipher.doFinal(data);
}
```
## Hex String
加密后的数据（byte[]）可以转化为 Hex String 储存
``` java
public String bytesToHexString(byte[] data){
return HexBin.encode(data);
}
```
当然，解密之前先吧Hex String 转化为byte[]。
``` java
public byte[] hexStringToBytes(String hexString){
byte[] bytes = new byte[hexString.length() / 2];
for (int i = 0; i < bytes.length; i++) {
bytes[i] = (byte) Integer.parseInt(hexString.substring(2 * i, 2 * i + 2), 16);
}
return bytes;
}
```