加密/解密：HMAC標籤在解密方法中不匹配

Question

我試圖編碼將加密/解密郵件的加密和解密方法。

在加密方法中，它將採用一個字符串。它將讀取公鑰並用於RSA密碼。然後，將使用具有AES密鑰和IV的AES密碼對消息進行加密。然後，通過使用HMAC密鑰，利用密文加密的AES生成HMAC標籤。 AES密鑰和HMAC密鑰連接在一起並通過RSA密碼加密。該方法將返回一個JSONObject，其中包含：RSA密文，AES密文，AES IV和HMAC標記。它們是轉換爲十六進制字符串的字節數組。

在解密方法中，它將採用將被解析的JSON對象。它將讀取將在RSA密碼中使用的私鑰。 RSA密碼將用於解密連接的密鑰。一旦解密，密鑰將被分離爲AES密鑰和HMAC密鑰。然後，將在AES密文上生成新的HMAC標籤。比較加密標籤和新標籤。如果它們相同，則解密AES密文並獲得消息。

當我運行我的代碼，沒有錯誤，但它不解密，因爲2個標籤不匹配。我不知道爲什麼。

公鑰和私鑰是從.pem文件轉換而來的.der文件。

請幫幫我。謝謝！

import java.security.*; 
import java.security.spec.*; 
import javax.crypto.*; 
import java.io.*; 
import java.nio.file.Files; 
import java.nio.file.Paths; 
import javax.crypto.spec.SecretKeySpec; 
import javax.crypto.spec.IvParameterSpec; 
import org.json.*; 
import javax.xml.bind.DatatypeConverter; 

public class CryptographicTools 
{ 
    /** 
    * This method encrypts a message 
    * @param message String message to be encrypted 
    * @return a JSONObject 
    */ 
    public JSONObject encryptMessage(String message) 
    { 
     JSONObject output = new JSONObject(); // instantiate JSONObject 

     try 
     { 
      //read in public key 
      byte[] publicKeyBytes = readKeyFromFile("public.der");//pem convert to der 

      //turn bytes into public key 
      X509EncodedKeySpec publicSpec = new X509EncodedKeySpec(publicKeyBytes); //encodes the bytes 
      KeyFactory keyFactory = KeyFactory.getInstance("RSA"); //make the key a RSA instance 

      //initialize RSA object and public key 
      Cipher RSAObject = Cipher.getInstance("RSA/ECB/OAEPWithSHA-256AndMGF1Padding"); //with OAEP 
      RSAObject.init(Cipher.ENCRYPT_MODE, keyFactory.generatePublic(publicSpec)); //create RSA encryption cipher with a generated public key 

      //generate 256-bit AES key 
      KeyGenerator keyGen = KeyGenerator.getInstance("AES");//generate AES Key 
      keyGen.init(256); //generate a key with 256 bits 
      SecretKey AESKey = keyGen.generateKey(); //generate AES key with 256 bits 

      //Create AES IV 
      SecureRandom randomByteGenerator = new SecureRandom();//secure generator to generate random byes for IV 
      byte[] AESKeyIVArray = new byte[16]; 
      randomByteGenerator.nextBytes(AESKeyIVArray);//get random bytes for iv 
      IvParameterSpec AES_IV = new IvParameterSpec(AESKeyIVArray); //iv object for AES object 

      //initialize AES object 
      Cipher AESObject = Cipher.getInstance("AES/CBC/PKCS5Padding"); 
      AESObject.init(Cipher.ENCRYPT_MODE, AESKey, AES_IV); //tell the AES object to encrypt 

      //encrypt message with AES 
      byte[] AESciphertext = AESObject.doFinal(message.getBytes()); 

      //generate 256-bit HMAC key 
      byte[] SHA256KeyArray = new byte[32];//256 bits 
      randomByteGenerator.nextBytes(SHA256KeyArray);//generate random bits for key 
      SecretKeySpec HMACKeySpec = new SecretKeySpec (SHA256KeyArray,"HmacSHA256"); //make the key 
      Mac HMAC = Mac.getInstance("HmacSHA256"); //initialize HMAC 
      HMAC.init(HMACKeySpec);//put key in cipher 
      byte [] HMACTag = HMAC.doFinal(AESciphertext);//generate HMAC tag 

      //concatenate AES and HMAC keys 
      byte[] AESKeyByte = AESKey.getEncoded();///turn AESKey to byte array 
      byte[] HMACKeySpecByte = HMACKeySpec.getEncoded();///turn HMAXKey to byte array 
      byte[] concatenatedKeys = new byte[AESKeyByte.length + HMACKeySpecByte.length];//new array for concatenated keys 

      //combine keys in new array 
      System.arraycopy(AESKeyByte, 0, concatenatedKeys, 0, AESKeyByte.length); 
      System.arraycopy(HMACKeySpecByte, 0, concatenatedKeys, AESKeyByte.length, HMACKeySpecByte.length); 

      //encrypt keys with RSA object 
      byte[] RSAciphertext = RSAObject.doFinal(concatenatedKeys); 

      //put RSA ciphertext, AES ciphertext, AES_IV and HMAC tag in JSon 
      //save byte[] as Strings in hex 
      output.put("RSAciphertext", DatatypeConverter.printHexBinary(RSAciphertext)); 
      output.put("AESciphertext", DatatypeConverter.printHexBinary(AESciphertext)); 
      output.put("AES_IV", DatatypeConverter.printHexBinary(AES_IV.getIV())); 
      output.put("HMACTag", DatatypeConverter.printHexBinary(HMACTag)); 
     } 
     catch (Exception e) 
     { 
      System.out.println("Error: " + e.toString() +e.getMessage()); //error message 
     } 

     return output; //return as JSON Object 
    } 

    /** 
    * This method decrypts a message 
    * @param jsonObjectEncrypted 
    * @return message as string 
    */ 
    public String decrypt (JSONObject jsonObjectEncrypted) 
    { 
     String message=""; 
     try 
     { 
      //recover RSA ciphertext from JSON 
      String RSACiphertextString=jsonObjectEncrypted.getString("RSAciphertext"); 
      byte[] recoveredRSAciphertext = DatatypeConverter.parseHexBinary(RSACiphertextString); //convert hex string to byte array 

      //recover AES ciphertext from JSON 
      String AESCiphertextString=jsonObjectEncrypted.getString("AESciphertext"); 
      byte[] recoveredAESciphertext = DatatypeConverter.parseHexBinary(AESCiphertextString); //convert hex string to byte array 

      //recover AES IV from JSON 
      String AES_IVString=jsonObjectEncrypted.get("AES_IV").toString(); 
      byte[] recoveredAES_IV = DatatypeConverter.parseHexBinary(AES_IVString); //convert hex string to byte array 
      //recover HMACTag from JSON 
      String HMACTagString=jsonObjectEncrypted.getString("HMACTag"); 
      byte[] recoveredHMACTag = DatatypeConverter.parseHexBinary(HMACTagString); //convert hex string to byte array 

      //read in private key 
      byte[] privateKeyBytes = readKeyFromFile("private.der");//pem convert to der 

      //turn bytes into private key 
      PKCS8EncodedKeySpec privateSpec = new PKCS8EncodedKeySpec(privateKeyBytes); 
      KeyFactory keyFactory = KeyFactory.getInstance("RSA"); 

      //initialize RSA object and private key 
      Cipher RSAObject = Cipher.getInstance("RSA/ECB/OAEPWithSHA-256AndMGF1Padding"); //with OAEP 
      RSAObject.init(Cipher.DECRYPT_MODE, keyFactory.generatePrivate(privateSpec)); //create RSA encryption cipher with a generated private key 

      //Decrypt concatenated keys with RSA object 
      byte[] concatenatedKeys = RSAObject.doFinal(recoveredRSAciphertext); 

      //split the concatenated keys 
      byte[] AESKey = new byte[concatenatedKeys.length/2]; 
      byte[] HMACKey = new byte[concatenatedKeys.length/2]; 
      System.arraycopy(concatenatedKeys, 0,AESKey,0,AESKey.length); //Copy half into AESKey 
      System.arraycopy(concatenatedKeys, AESKey.length,HMACKey,0,HMACKey.length); //Copy Other half into HMACKey 

      //generate HMACTag 
      SecretKeySpec HMACKeySpec = new SecretKeySpec (HMACKey,"HmacSHA256"); //make the key 
      Mac HMAC = Mac.getInstance("HmacSHA256"); 
      HMAC.init(HMACKeySpec);//initialize with HMAC Key 
      byte [] newHMACTag = HMAC.doFinal(recoveredAESciphertext); //generate HMACTag with AES Ciphertext 

      if(recoveredHMACTag.equals(newHMACTag)) //encrypt message if tags are equal 
      { 
       //initialize AES object 
       Cipher AESObject = Cipher.getInstance("AES/CBC/PKCS5Padding"); 
       AESObject.init(Cipher.DECRYPT_MODE, new SecretKeySpec (AESKey,"AES"), new IvParameterSpec(recoveredAES_IV)); //tell the AES object to encrypt 
       message = new String (AESObject.doFinal(recoveredAESciphertext), "US-ASCII");//encrypt AES ciphertext and save as string 

      } 
      else 
      { 
       System.out.println("Message cannot be decrypted."); 
      } 


     } 
     catch (Exception e) 
     { 
      System.out.println("Error: "+e.toString()+": "+e.getMessage()); //error message 
     } 

     return message; //return plaintext 
    } 

    /** 
    * This method reads bytes of a key from a file into a byte array 
    * @param fileName type of key 
    * @return byte array 
    * @throws IOException 
    */ 
    public byte[] readKeyFromFile(String fileName) throws IOException 
    { 
     return Files.readAllBytes(Paths.get(fileName)); 
    } 

} 

Answer 1

的Java數組沒有實現.equals()你想讓它（info）的方式。嘗試更換此檢查：

recoveredHMACTag.equals(newHMACTag) 

通過這一個：

java.util.Arrays.equals(recoveredHMACTag, newHMACTag) 

我不能說這是所有可能會造成它出問題，但它是我會檢查的第一件事。