RSA加解密開始構建工具類就是舉步維艱，官方文檔雖然很全，但是還是有很多小瑕疵，在自己經過幾天的時間，徹底解決了中文亂碼的問題、分段加密的問題。

首先看官方示例代碼(以RSA非對稱加解密（多次調用doFinal實現分段）為例：)：

import cryptoFramework from "@ohos.security.cryptoFramework"

function stringToUint8Array(str) {
  var arr = [];
  for (var i = 0, j = str.length; i < j; ++i) {
    arr.push(str.charCodeAt(i));
  }
  var tmpArray = new Uint8Array(arr);
  return tmpArray;
}

// 字節流轉成可理解的字符串
function uint8ArrayToString(array) {
  let arrayString = '';
  for (let i = 0; i < array.length; i++) {
    arrayString += String.fromCharCode(array[i]);
  }
  return arrayString;
}

function encryptLongMessagePromise() {
  let globalPlainText = "This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
  "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
  "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
  "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
  "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
  "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
  "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!" +
  "This is a long plainTest! This is a long plainTest! This is a long plainTest! This is a long plainTest!";
  let globalCipherOutput;
  let globalDecodeOutput;
  var globalKeyPair;
  let plainTextSplitLen = 64; // RSA每次加解密允許的原文長度大小與密鑰位數和填充模式等有關，詳細規格內容見overview文檔
  let cipherTextSplitLen = 128; // RSA密鑰每次加密生成的密文數據長度計算方式：密鑰位數/8
  let keyGenName = "RSA1024";
  let cipherAlgName = "RSA1024|PKCS1";
  let asyKeyGenerator = cryptoFramework.createAsyKeyGenerator(keyGenName); // 創建非對稱密鑰生成器對象
  let cipher = cryptoFramework.createCipher(cipherAlgName); // 創建加密Cipher對象
  let decoder = cryptoFramework.createCipher(cipherAlgName); // 創建解密Decoder對象
  return new Promise((resolve, reject) = > {
    setTimeout(() = > {
      resolve("testRsaMultiDoFinal");
    }, 10);
  }).then(() = > {
    return asyKeyGenerator.generateKeyPair(); // 生成rsa密鑰
  }).then(keyPair = > {
    globalKeyPair = keyPair; // 保存到密鑰對全局變量
    return cipher.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, globalKeyPair.pubKey, null);
  }).then(async () = > {
    globalCipherOutput = [];
    // 將原文按64字符進行拆分，循環調用doFinal進行加密，使用1024bit密鑰時，每次加密生成128B長度的密文
    for (let i = 0; i < (globalPlainText.length / plainTextSplitLen); i++) {
      let tempStr = globalPlainText.substr(i * plainTextSplitLen, plainTextSplitLen);
      let tempBlob = { data : stringToUint8Array(tempStr) };
      let tempCipherOutput = await cipher.doFinal(tempBlob);
      globalCipherOutput = globalCipherOutput.concat(Array.from(tempCipherOutput.data));
    }
    console.info(`globalCipherOutput len is ${globalCipherOutput.length}, data is: ${globalCipherOutput.toString()}`);
    return;
  }).then(() = >{
    return decoder.init(cryptoFramework.CryptoMode.DECRYPT_MODE, globalKeyPair.priKey, null);
  }).then(async() = > {
    globalDecodeOutput = [];
    // 將密文按128B進行拆分解密，得到原文后進行拼接
    for (let i = 0; i < (globalCipherOutput.length / cipherTextSplitLen); i++) {
      let tempBlobData = globalCipherOutput.slice(i * cipherTextSplitLen, (i + 1) * cipherTextSplitLen);
      let message = new Uint8Array(tempBlobData);
      let tempBlob = { data : message };
      let tempDecodeOutput = await decoder.doFinal(tempBlob);
      globalDecodeOutput += uint8ArrayToString(tempDecodeOutput.data);
    }
    if (globalDecodeOutput === globalPlainText) {
      console.info(`encode and decode success`);
    } else {
      console.info(`encode and decode error`);
    }
    return;
  }).catch(error = > {
    console.error(`catch error, ${error.code}, ${error.message}`);
  })
}

let plainTextSplitLen = 64; // RSA每次加解密允許的原文長度大小與密鑰位數和填充模式等有關，詳細規格內容見overview文檔

注意點：在解密中，這句代碼就是產生中文亂碼的關鍵。

globalDecodeOutput += uint8ArrayToString(tempDecodeOutput.data);

好，加上我的代碼

加密：

/**
 * 測試RSA加密
 */
export function textRsaEncryption(value: string) {
  let keyGenName = "RSA1024";
  let cipherAlgName = "RSA1024|PKCS1";
  //64 RSA每次加解密允許的原文長度大小與密鑰位數和填充模式等有關，詳細規格內容見overview文檔
  let plainTextSplitLen = 117;
  let globalKeyPair; //密鑰對
  let globalEncryptionOutput; //加密輸出
  let arrTest = StringUtils.string2Uint8Array1(value);
  //創建非對稱密鑰生成器對象
  let asyKeyGenerator = cryptoFramework.createAsyKeyGenerator(keyGenName);
  // 創建加密Cipher對象
  let cipherEncryption = cryptoFramework.createCipher(cipherAlgName);

  return new Promise((resolve, reject) = > {
    setTimeout(() = > {
      resolve("textRsaEncryption");
    }, 10);
  })
    .then(() = > {
      let base64 = Base64.getInstance()
      let pubKeyBlob = { data: new Uint8Array(base64.decode(publicKey)) }
      let priKeyBlob = { data: new Uint8Array(base64.decode(privateKey)) }
      return asyKeyGenerator.convertKey(pubKeyBlob, priKeyBlob);
    })
    .then(keyPair = > {
      globalKeyPair = keyPair; // 保存到密鑰對全局變量
      return cipherEncryption.init(cryptoFramework.CryptoMode.ENCRYPT_MODE, globalKeyPair.pubKey, null);
    }).then(async () = > {
      globalEncryptionOutput = [];

      // 將原文按64字符進行拆分，循環調用doFinal進行加密，使用1024bit密鑰時，每次加密生成128B長度的密文
      for (let i = 0; i < (arrTest.length / plainTextSplitLen); i++) {
        let tempArr = arrTest.slice(i * plainTextSplitLen, (i + 1) * plainTextSplitLen);
        let tempBlob = { data: tempArr };
        let tempCipherOutput = await cipherEncryption.doFinal(tempBlob);
        globalEncryptionOutput = globalEncryptionOutput.concat(Array.from(tempCipherOutput.data));
      }
      let base64 = Base64.getInstance()
      let enStr = base64.encode(globalEncryptionOutput)
      LogUtils.i("加密總長度：" + globalEncryptionOutput.length + "n生成加密串：n" + enStr)
      return enStr
    })
    .catch(error = > {
      LogUtils.i(`加密異常, ${error.code}, ${error.message}`);
    })
}復制

解密：

/**
 * 測試RSA解密
 */
export function textRsaDecryption(value: string) {
  let keyGenName = "RSA1024";
  let cipherAlgName = "RSA1024|PKCS1";
  // RSA密鑰每次加密生成的密文數據長度計算方式：密鑰位數/8
  let cipherTextSplitLen = 128;
  let globalKeyPair; //密鑰對
  //創建非對稱密鑰生成器對象
  let asyKeyGenerator = cryptoFramework.createAsyKeyGenerator(keyGenName);
  // 創建解密Decoder對象
  let cipherDecryption = cryptoFramework.createCipher(cipherAlgName);

  return new Promise((resolve, reject) = > {
    setTimeout(() = > {
      resolve("textRsaEncryption");
    }, 10);
  })
    .then(() = > {
      let base64 = Base64.getInstance()
      let pubKeyBlob = { data: new Uint8Array(base64.decode(publicKey)) }
      let priKeyBlob = { data: new Uint8Array(base64.decode(privateKey)) }
      return asyKeyGenerator.convertKey(pubKeyBlob, priKeyBlob);
    })
    .then(keyPair = > {
      globalKeyPair = keyPair; // 保存到密鑰對全局變量
      return cipherDecryption.init(cryptoFramework.CryptoMode.DECRYPT_MODE, globalKeyPair.priKey, null);
    }).then(async () = > {
      let base64 = Base64.getInstance()
      let globalCipherOutput1 = new Uint8Array(base64.decode(value))
      let len = globalCipherOutput1.length
      //解密輸出
      let globalDecryptionOutput = new Uint8Array(len);
      let globalOffset = 0
      // 將密文按128B進行拆分解密，得到原文后進行拼接
      for (let i = 0; i < (len / cipherTextSplitLen); i++) {
        let tempBlobData = globalCipherOutput1.subarray(i * cipherTextSplitLen, (i + 1) * cipherTextSplitLen);
        let message = new Uint8Array(tempBlobData);
        let tempBlob = { data: message };
        let tempDecodeOutput = await cipherDecryption.doFinal(tempBlob);
        //存入數組 解決邊累加邊轉中文時 字節錯亂出現亂碼
        globalDecryptionOutput.set(tempDecodeOutput.data, globalOffset)
        //偏移量
        globalOffset += tempDecodeOutput.data.byteLength
      }
      let result = StringUtils.uint8Array2String(globalDecryptionOutput)
      LogUtils.i("解密串:cipherAlgName[" + cipherAlgName + "]n" + result);
    })
    .catch(error = > {
      LogUtils.i(`解密異常,cipherAlgName[${cipherAlgName}] ${error.code}, ${error.message}`);
    })
}復制

運行代碼：

Text("RSA加解密聯測")
          .TextNormalStyle()
          .fontSize(16)
          .fontWeight(FontWeight.Normal)
          .fontColor(Color.White)
          .textAlign(TextAlign.Center)
          .margin({ left: 5 })
          .layoutWeight(1)
          .onClick(() = > {
            let globalPlainText = ""
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "一二三四五六七八九十"
            globalPlainText += "123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/123456789/"
            globalPlainText += "SDK向DevEco Studio提供全量API，DevEco Studio識別開發者項目中選擇的設備形態，找到該設備的支持能力集，篩選支持能力集包含的API并提供API聯想"
            //
            textRsaEncryption(globalPlainText)
              .then(enStr = > {
                if (enStr) textRsaDecryption(enStr)
              })
          })
      }
      .width('100%')
      .height(50)
      .margin({ top: 10 })
      .padding(5)復制

運行結果：

終于大功告成！！

審核編輯 黃宇