vue 3.0 国密sm2算法加密解密文件流

  针对文件流加密需要考虑性能问题，所以选择部分文件字节加密，破坏文件内容，达到用户不能随意下载打开文件

ts文件：
import { sm2 } from 'sm-crypto';
import { Buffer } from 'buffer';
// 公钥-示例
const publickey_buffer =
  '0451d6cad24f7719edd7e4e6fccbb2fa9867aec2e609ffeb69ec17570e41daf3073d5e8be23828b41e70c92445e1bc30a992d51c425a83ec0a1c0988b87dce0967';
// 私钥-示例
const privateKey_buffer = '24417f87b5e72f7d6f624b5a82e3c53193b819926dd914d772e179b78d9b4914';

// 截取文件流部分字节加密
export const encryptBufferSlice = function (file, fileName) {
  getArrayBuffer(file, (result) => {
    const buffer = Buffer.from(result, 'base64');

    const sliceBuffer_head = buffer.slice(0, 100000);

    const sliceBuffer_tail = buffer.slice(100000);

    const encryptStr = '04' + sm2.doEncrypt(sliceBuffer_head, publickey_buffer, 1);

    const encryptBufferArr = Buffer.from(encryptStr, 'hex');

    const concatBuffer = Buffer.concat([encryptBufferArr, sliceBuffer_tail]);

    const blob = new Blob([concatBuffer]);
    downBlob(blob, fileName);
  });
};

// 截取文件流部分字节解密
export const decryptBufferSlice = function (file, fileName) {
  getArrayBuffer(file, (result) => {
    const buffer = Buffer.from(result, 'hex');

    const sliceBuffer_head = buffer.slice(0, 100097);

    const sliceBuffer_tail = buffer.slice(100097);

    let strHex = sliceBuffer_head.toString('hex');
    strHex = strHex.slice(2);

    const decryptStr = sm2.doDecrypt(strHex, privateKey_buffer, 1, { output: 'array' });

    const decryptBuffer = Buffer.from(decryptStr, 'base64');

    const concatBuffer = Buffer.concat([decryptBuffer, sliceBuffer_tail]);

    const blob = new Blob([concatBuffer]);
    downBlob(blob, fileName);
  });
};

// 获取图片ArrayBuffer
export const getArrayBuffer = function (file, callback: (result) => void) {
  const reader = new FileReader();
  reader.readAsArrayBuffer(file);
  reader.addEventListener('load', () => callback(reader.result));
};

// 下载文件
const downBlob = function (blob, filename) {
  const url = URL.createObjectURL(blob);
  const a = document.createElement('a');

  a.setAttribute('href', url);
  a.setAttribute('download', filename);

  const event = document.createEvent('MouseEvent');
  event.initMouseEvent('click');

  a.dispatchEvent(event);
};

vue文件引用:
  const handleBeforeUpload = function (file) {
    // 解密
    decryptBufferSlice(file, '截取前100097字节解密文件.ai');
    // 加密
    // encryptBufferSlice(file, '截取前100000字节加密文件.ai');
    return false;
  };