想了解一下SM4相关案例

async function SM4ED(plainText: string) { 
 
  let sm4Generator = cryptoFramework.createSymKeyGenerator('SM4_128'); 
  let cipher = cryptoFramework.createCipher('SM4_128|CBC|PKCS7'); 
  let decoder = cryptoFramework.createCipher('SM4_128|CBC|PKCS7'); 
  let input: cryptoFramework.DataBlob = { data: stringToUint8Array(plainText) }; 
  let keydata: cryptoFramework.DataBlob = { data: stringToUint8Array('yc1436w86vhys51r') }; //密钥 
  let ivdata: cryptoFramework.DataBlob = { data: stringToUint8Array('43pr5253zf5mm7jd') }; //偏移 
  let iv: cryptoFramework.IvParamsSpec = { iv: ivdata, algName: 'IvParamsSpec'} //cbc模式的参数 
  let key: cryptoFramework.SymKey 
  try { 
    key = await sm4Generator.convertKey(keydata); 
    // 加密 
    // 最后一个参数是偏移量的设置，如果没有则为null，下面解密同理 
    await cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, key, iv); 
    let cipherData = await cipher.doFinal(input) 
    //解密 
    await decoder.init(cryptoFramework.CryptoMode.DECRYPT_MODE, key, iv); 
    let result = await decoder.doFinal(cipherData); 
    //解密后的明文 
    let str = uint8ArrayToString(result.data) 
    AlertDialog.show({ message: 'decrypt success ==>' + str }) 
  } catch (err) { 
    console.error(err) 
  } 
 
}