国密算法SM4 对文件加解密

说明：调用开源bcprov-jdk15on 加密算法工具，使用SM4算法，对文件进行加密、解密；文件流的操作使用hutool工具包来实现。

• 引用依赖

          <dependency>
              <groupId>org.bouncycastle</groupId>
              <artifactId>bcprov-jdk15on</artifactId>
              <version>1.54</version>
          </dependency>
  
          <!-- hutool 工具包 -->
          <dependency>
              <groupId>cn.hutool</groupId>
              <artifactId>hutool-all</artifactId>
              <version>4.6.10</version>
          </dependency>
  

• 生成128位的Key

  public static final int KEY_SIZE = 128;    
  
  public static byte[] generateKey(int keySize) throws Exception { 
          KeyGenerator kg = KeyGenerator.getInstance(ALGORITHM_NAME, BouncyCastleProvider.PROVIDER_NAME);
          kg.init(keySize, new SecureRandom());
          return kg.generateKey().getEncoded();
      }
  

• 生成密钥

      public static void main(String[] args) throws Exception { 
  
          //生成Key
          byte[] bytes = generateKey(KEY_SIZE);
          String key = ByteUtils.toHexString(bytes);
          System.out.println("密钥：");
          System.out.println(key);
      }
  

• 文件加密、解密，贴上完整的可执行的代码

  public class SM4FileEncrypt { 
      static{ 
          if (Security.getProvider(BouncyCastleProvider.PROVIDER_NAME) == null){ 
              //No such provider: BC
              Security.addProvider(new BouncyCastleProvider());
          }
      }
  
      //生成 Cipher
      public static Cipher generateCipher(int mode,byte[] keyData) throws InvalidKeyException, NoSuchPaddingException, NoSuchAlgorithmException, NoSuchProviderException { 
          Cipher cipher = Cipher.getInstance("SM4/ECB/PKCS5Padding", BouncyCastleProvider.PROVIDER_NAME);
          Key sm4Key = new SecretKeySpec(keyData, "SM4");
          cipher.init(mode, sm4Key);
          return cipher;
      }
  
  
      //加密文件
      public static void encryptFile(byte[] keyData,String sourcePath,String targetPath){ 
          //加密文件
          try { 
              Cipher cipher = generateCipher(Cipher.ENCRYPT_MODE,keyData);
              CipherInputStream cipherInputStream = new CipherInputStream(new FileInputStream(sourcePath), cipher);
              FileUtil.writeFromStream(cipherInputStream, targetPath);
              IoUtil.close(cipherInputStream);
          } catch (InvalidKeyException e) { 
              e.printStackTrace();
          } catch (NoSuchPaddingException e) { 
              e.printStackTrace();
          } catch (NoSuchAlgorithmException e) { 
              e.printStackTrace();
          } catch (NoSuchProviderException e) { 
              e.printStackTrace();
          } catch (FileNotFoundException e) { 
              e.printStackTrace();
          }
      }
  
  
    /** * 解密文件 * @param sourcePath 待解密的文件路径 * @param targetPath 解密后的文件路径 */
    public static void decryptFile(byte[] keyData,String sourcePath, String targetPath) { 
        FileInputStream in =null;
        ByteArrayInputStream byteArrayInputStream =null;
        OutputStream out = null;
        CipherOutputStream cipherOutputStream=null;
        try { 
            in = new FileInputStream(sourcePath);
            byte[] bytes = IoUtil.readBytes(in);
            byteArrayInputStream = IoUtil.toStream(bytes);
  
             Cipher cipher = generateCipher(Cipher.DECRYPT_MODE,keyData);
  
            out = new FileOutputStream(targetPath);
            cipherOutputStream = new CipherOutputStream(out, cipher);
            IoUtil.copy(byteArrayInputStream, cipherOutputStream);
        } catch (IOException e) { 
            e.printStackTrace();
        } catch (NoSuchPaddingException e) { 
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) { 
            e.printStackTrace();
        } catch (InvalidKeyException e) { 
            e.printStackTrace();
        } catch (NoSuchProviderException e) { 
            e.printStackTrace();
        }finally { 
            IoUtil.close(cipherOutputStream);
            IoUtil.close(out);
            IoUtil.close(byteArrayInputStream);
            IoUtil.close(in);
        }
    }
  
      public static void main(String[] args) throws Exception { 
  
          String sp = "E:\\bjsasc\\文件加解密\\原始文件.docx";//原始文件
          String dp = "E:\\bjsasc\\文件加解密\\加密文件.docx";//加密后文件
          String dp2 = "E:\\bjsasc\\文件加解密\\解密文件.docx";//解密后文件
  
          String key = "05d986b1141227cb20d46d0b5687c4f5";
          byte[] keyData = ByteUtils.fromHexString(key);
          //加密文件
          encryptFile(keyData,sp,dp);
  
          //解密文件
          decryptFile(keyData,dp,dp2);
      }
  }