java实现SM4 ctr加解密
时间: 2023-07-26 08:17:45 浏览: 110
以下是Java实现SM4 CTR模式加解密的示例代码:
```java
import org.bouncycastle.crypto.BlockCipher;
import org.bouncycastle.crypto.engines.SM4Engine;
import org.bouncycastle.crypto.modes.SICBlockCipher;
import org.bouncycastle.crypto.params.KeyParameter;
import org.bouncycastle.crypto.params.ParametersWithIV;
import org.bouncycastle.util.encoders.Hex;
import java.security.SecureRandom;
public class SM4CTR {
private static final int BLOCK_SIZE = 16;
public static void main(String[] args) {
String keyStr = "0123456789abcdef0123456789abcdef";
String ivStr = "0123456789abcdef";
String plainText = "Hello, SM4!";
byte[] key = Hex.decode(keyStr);
byte[] iv = Hex.decode(ivStr);
byte[] plain = plainText.getBytes();
byte[] encrypted = SM4CTR.encrypt(key, iv, plain);
System.out.println("Encrypted: " + Hex.toHexString(encrypted));
byte[] decrypted = SM4CTR.decrypt(key, iv, encrypted);
System.out.println("Decrypted: " + new String(decrypted));
}
public static byte[] encrypt(byte[] key, byte[] iv, byte[] plain) {
BlockCipher engine = new SM4Engine();
SICBlockCipher cipher = new SICBlockCipher(engine);
KeyParameter keyParam = new KeyParameter(key);
ParametersWithIV params = new ParametersWithIV(keyParam, iv);
cipher.init(true, params);
byte[] encrypted = new byte[plain.length];
int offset = 0;
while (offset < plain.length) {
int len = Math.min(BLOCK_SIZE, plain.length - offset);
cipher.processBlock(new byte[BLOCK_SIZE], 0, BLOCK_SIZE, encrypted, offset);
for (int i = 0; i < len; i++) {
encrypted[offset + i] ^= plain[offset + i];
}
offset += len;
}
return encrypted;
}
public static byte[] decrypt(byte[] key, byte[] iv, byte[] encrypted) {
BlockCipher engine = new SM4Engine();
SICBlockCipher cipher = new SICBlockCipher(engine);
KeyParameter keyParam = new KeyParameter(key);
ParametersWithIV params = new ParametersWithIV(keyParam, iv);
cipher.init(true, params);
byte[] decrypted = new byte[encrypted.length];
int offset = 0;
while (offset < encrypted.length) {
int len = Math.min(BLOCK_SIZE, encrypted.length - offset);
cipher.processBlock(new byte[BLOCK_SIZE], 0, BLOCK_SIZE, decrypted, offset);
for (int i = 0; i < len; i++) {
decrypted[offset + i] ^= encrypted[offset + i];
}
offset += len;
}
return decrypted;
}
public static byte[] generateIV() {
byte[] iv = new byte[BLOCK_SIZE];
SecureRandom random = new SecureRandom();
random.nextBytes(iv);
return iv;
}
}
```
其中,使用了BouncyCastle库中的SM4加密算法实现。在加密和解密过程中,采用了SICBlockCipher作为CTR模式的实现,使用初始计数器为全零的方式进行加解密。在加密过程中,将伪随机数流与明文异或得到密文,而在解密过程中,则是将伪随机数流与密文异或得到明文。注意,这里计数器不能重复使用,因此每次加密和解密时,都需要重新生成一个随机的IV,并将其与计数器组合成初始计数器。
相关推荐
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)