HarmonyOS AES加密中文字符串，解密出来时空字符串

可以参考这个demo:

import { cryptoFramework } from '@kit.CryptoArchitectureKit';
import { buffer, HashMap, util, xml } from '@kit.ArkTS';
let key = 'ZkQQVV126FtQ/jaxWoKeGg=='
let cipherAlgName = 'AES128|CBC|PKCS7';
let symAlgName = 'AES128';
let base64Helper = new util.Base64Helper;
@Entry
@Component
struct Index {
  @State message: string = 'Hello World';
  private fileDir: string = ''

  build() {
    Column() {
      Scroll() {
        Text(this.message)
          .id('HelloWorld')
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .alignRules({
            center: { anchor: '__container__', align: VerticalAlign.Center },
            middle: { anchor: '__container__', align: HorizontalAlign.Center }
          })
      }

      Button('加解密数据')
        .onClick(() => {
          let str =  '{name:"张三"}'
          let xmlContent1 = stringToUint8Array(str)
          //加密文件
          let plainText1: cryptoFramework.DataBlob = { data: xmlContent1 };
          this.aesEcryptAll(plainText1, key)
        })

    }
    .height('100%')
    .width('100%')
  }

  async AES_CBC_Update(plainText: cryptoFramework.DataBlob) {
    //解密
    await this.aesDecryptAll(plainText, key);
  }

  async aesEcryptAll(globalCipherText: cryptoFramework.DataBlob, key: string) {
    let globalPlainText = "";
    try {
      let globalCipher = cryptoFramework.createCipher(cipherAlgName);
      let symKeyGenerator = cryptoFramework.createSymKeyGenerator(symAlgName);
      /*
      * 偏移量
      * */
      let cbcParamsSpec: cryptoFramework.IvParamsSpec = {
        iv: { data: stringToUint8Array("your-iv-your-iva") },
        algName: 'IvParamsSpec'
      };
      let dataUint8Array = base64Helper.decodeSync(key)
      let keyBlob: cryptoFramework.DataBlob = { data: dataUint8Array }
      let promiseSymKey = await symKeyGenerator.convertKey(keyBlob)
      await globalCipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, promiseSymKey, cbcParamsSpec);
      let updateOutput = await globalCipher.update(globalCipherText);
      let finalOutput = await globalCipher.doFinal(null);
      //let plainText: cryptoFramework.DataBlob = { data: finalOutput };

      this.AES_CBC_Update(finalOutput)//加密之后紧跟着加密
      globalPlainText = uint8ArrayToString(finalOutput.data)

    } catch (err) {
      console.log(err.message)
    }
  }

  // 解密
  async aesDecryptAll(globalCipherText: cryptoFramework.DataBlob, key: string) {
    let globalPlainText = "";
    try {
      let globalCipher = cryptoFramework.createCipher(cipherAlgName);
      let symKeyGenerator = cryptoFramework.createSymKeyGenerator(symAlgName);
      /*
      * 偏移量
      * */
      let cbcParamsSpec: cryptoFramework.IvParamsSpec = {
        iv: { data: stringToUint8Array("your-iv-your-iva") },
        algName: 'IvParamsSpec'
      };
      let dataUint8Array = base64Helper.decodeSync(key)
      let keyBlob: cryptoFramework.DataBlob = { data: dataUint8Array }
      let promiseSymKey = await symKeyGenerator.convertKey(keyBlob)
      await globalCipher.init(cryptoFramework.CryptoMode.DECRYPT_MODE, promiseSymKey, cbcParamsSpec);
      let updateOutput = await globalCipher.update(globalCipherText);
      let finalOutput = await globalCipher.doFinal(null);
      globalPlainText = uint8ArrayToString(finalOutput.data)      //解密后的明文
    } catch (err) {
      console.log(err.message)
    }
  }
}
// 字符串转成字节流
function stringToUint8Array(str: string) {
  return new Uint8Array(buffer.from(str, 'utf-8').buffer);
}

// 字节流转成可理解的字符串
function uint8ArrayToString(array: Uint8Array) {
  // 将UTF-8编码转换成Unicode编码
  let out: string = "";
  let index: number = 0;
  let len: number = array.length;
  while (index < len) {
    let character = array[index++];
    switch (character >> 4) {
      case 0:
      case 1:
      case 2:
      case 3:
      case 4:
      case 5:
      case 6:
      case 7:
        out += String.fromCharCode(character);
        break;
      case 12:
      case 13:
        out += String.fromCharCode(((character & 0x1F) << 6) | (array[index++] & 0x3F));
        break;
      case 14:
        out += String.fromCharCode(((character & 0x0F) << 12) | ((array[index++] & 0x3F) << 6) |
          ((array[index++] & 0x3F) << 0));
        break;
      default:
        break;
    }
  }
  return out;
}