HarmonyOS AES加密相关

请参考示例：

let base64 = new util.Base64Helper();
let keyData = new Uint8Array([83, 217, 231, 76, 28, 113, 23, 219, 250, 71, 209, 210, 205, 97, 32, 159]);

let symKey = await genSymKeyByData(keyData);
let base64Key = base64.encodeToStringSync( new Uint8Array(buffer.from(JSON.stringify(symKey)).buffer));
console.error('symKey: ' + base64Key);

输出： symKey: e30=