AES分段加解密，分组模式采用CBC，填充方式采用PKCS7，对超大量数据进行分段加解密

import cryptoFramework from '@ohos.security.cryptoFramework'; 
import { BusinessError } from '@ohos.base'; 
import buffer from '@ohos.buffer'; 
  
  
  
// 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; 
} 
  
function genIvParamsSpec() { 
  let arr = [71,67,48,86,67,57,77,86,84,53,55,72,72,85,52,68]; 
  let dataIv = new Uint8Array(arr); 
  let ivBlob: cryptoFramework.DataBlob = { data: dataIv }; 
  let ivParamsSpec: cryptoFramework.IvParamsSpec = { 
    algName: "IvParamsSpec", 
    iv: ivBlob 
  }; 
  return ivParamsSpec; 
} 
  
async function testAesMultiUpdate(plainText: string) { 
    let symAlgName = 'AES128'; 
    let length = 30; 
    let symKeyGenerator = cryptoFramework.createSymKeyGenerator(symAlgName); 
    // 创建 Cipher 实例。 
    let cipherAlgName = 'AES128|CBC|PKCS7'; 
    let globalCipher = cryptoFramework.createCipher(cipherAlgName); 
    let globalCipherText: cryptoFramework.DataBlob; 
    let globalKey: cryptoFramework.SymKey; 
    let globalPlainText = ''; 
    let result = new Uint8Array(); 
    let str = ""; 
    let data: cryptoFramework.DataBlob 
    let startEecrypt = 0 
    let endEecrypt = 0 
    let startDecrypt = 0 
    let endDecrypt = 0 
  
    // 使用密钥生成器随机生成 128 位对称密钥。 
    let promiseSymKey = await symKeyGenerator.generateSymKey(); 
    await globalCipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, promiseSymKey, genIvParamsSpec()); 
    let updateOutput: cryptoFramework.DataBlob; 
  
    while (plainText.length > 0) { 
      const contentCurr = plainText.substring(0, length); // 超过长度会取最长 
      plainText = plainText.substring(length, plainText.length); // 起始点大于长度会返回"" 
      let messageBlob: cryptoFramework.DataBlob = { data: stringToUint8Array(contentCurr) }; 
      updateOutput = await globalCipher.update(messageBlob); 
      if (updateOutput != null) { 
        let mergeText = new Uint8Array(result.length + updateOutput.data.length); 
        mergeText.set(result); 
        mergeText.set(updateOutput.data, result.length); 
        result = mergeText; 
      } 
    } 
  
    globalCipherText = { data: result } 
    startEecrypt = new Date().getTime() 
    data = await globalCipher.doFinal(null); 
    endEecrypt = new Date().getTime() 
    console.log("TEST==jiami" + (endEecrypt - startEecrypt)) 
    let mergeText = new Uint8Array(result.length + data.data.length); 
    mergeText.set(result); 
    mergeText.set(data.data, result.length); 
    result = mergeText; 
  
    let resultTemp = new Uint8Array(); 
    let contentTemp = result; 
    console.log("TEST==加密成功") 
    await globalCipher.init(cryptoFramework.CryptoMode.DECRYPT_MODE, promiseSymKey, genIvParamsSpec()); 
  
  
    console.log("TEST==长度" + contentTemp.length) 
  
    while (contentTemp.length > 0) { 
      const contentCurr = contentTemp.slice(0, length); // 超过长度会取最长 
      contentTemp = contentTemp.slice(length, contentTemp.length); // 起始点大于长度会返回"" 
      let messageBlob: cryptoFramework.DataBlob = { data: contentCurr }; 
      let updateOutput = await globalCipher.update(messageBlob); // 按细分市场更新。 
      if (updateOutput != null) { 
        let mergeText = new Uint8Array(resultTemp.length + updateOutput.data.length); 
        mergeText.set(resultTemp); 
        mergeText.set(updateOutput.data, resultTemp.length); 
        resultTemp = mergeText; 
      } 
    } 
  
    //明文结果 
    str = uint8ArrayToString(resultTemp) 
    startEecrypt = new Date().getTime() 
    let mingwen: cryptoFramework.DataBlob 
    mingwen = await globalCipher.doFinal(null); 
    endEecrypt = new Date().getTime() 
    console.log("TEST== jiemi:" + (endEecrypt - startEecrypt)) 
  
    if (mingwen != null) { 
      str = str + uint8ArrayToString(mingwen.data); 
    } 
    AlertDialog.show({ message: str }); 
    console.info(`decrypt output: ${str}`); 
    endEecrypt = new Date().getTime() 
    console.log("TEST== startEecrypt:" + startEecrypt) 
    console.log("TEST== endEecrypt:" + endEecrypt) 
  
  
}