Android - 流不能正確讀取數組

Question

我目前正在研究我的Raspberry Pi和我的Android設備之間的連接。 這個連接是用blowfish加密的，似乎可以在較小的尺寸下正常工作（通常低於1 kB）。在下一步中，我嘗試從我的Pi發送一張照片到我的設備，該設備應該被加密。我的設備拋出異常javax.crypto.BadPaddingException: pad block corrupted，經過一些調試後，我發現大約90％的數據傳輸被設置爲零（使用大小爲2444368的數組進行測試，在位置212536之後所有數據都爲零）。

我的第一個猜測是Android無法爲我的陣列分配足夠的內存，但因爲沒有任何異常告訴我，所以我告訴Android，我的應用程序通過largeHeap=true使用很多內存，這不是問題了。這可能是因爲我對Android的工作方式不夠了解，所以我想請你幫助我。有問題的零部件（EncryptionUtil沒有顯示，這不是問題的一部分）：

客戶端：

public final byte[] readWithAppend() throws IOException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, NoSuchAlgorithmException, NoSuchPaddingException{ 
    byte[] b = new byte[read()]; //works fine, tells me the size of the array 
    System.out.println("Trying to read an array with the size " + b.length); 
    in.read(b,0,b.length);//No Exception here, so allocation works 
    if(b.length >= 10000){ //Just some debug for me to compare both sides, server and client. 
     File f; 
     FileOutputStream out = new FileOutputStream(f = new File(debugFile,EncryptionUtil.randomString(80))); 
     System.out.println("PATH: " + f); 
     out.write(b);out.close(); 
    } 
    System.out.println("After position " + searchPos(b) + " everything is 0 ?!?!?"); 
    b = EncryptionUtil.decrypt(enc, b, sessionKey); //The Exception gets thrown here. 
    return b; 
} 

private int searchPos(byte[] b){ 
    int pos = b.length; 
    for(int i = b.length-1;i >= 0;i--){ 
     if(b[i] != 0)return pos; 
     else pos--; 
    } 
    return pos; 
} 

Serverside集團：

private final void write(byte[] b,int off,int len,boolean appendLength) throws IOException{ 
    try { 
     byte[] b2; 
     if(len != b.length || off != 0){ //Just ignore this case 
      byte[] buffer = new byte[len-off];System.arraycopy(b, off, buffer, 0, len); 
      b2 = EncryptionUtil.encrypt(enc, buffer, sessionKey); 
     }else{ //This is the case we have to look at 
      b2 = EncryptionUtil.encrypt(enc, b, sessionKey); 
      System.out.println("Sending an array with the size " + b2.length); 
      System.out.println("Decrypting to check for mistakes"); 
      EncryptionUtil.decrypt(SymmetricEncryption.Blowfish, b2, sessionKey); //Debug. 
      if(b2.length >= 10000){ //Again, debug to compare the both files 
       FileOutputStream out2 = new FileOutputStream(new File("serverFile")); 
       out2.write(b2);out2.close(); 
      } 
     } 
     if(appendLength)write(b2.length); //Works as well 
     System.out.println("Length: " + b2.length + "; only writing: " + ((int)len/b.length)*b2.length);// it writes everything. 
     out.write(b2,0,((int)len/b.length)*b2.length); //The flush part happens somewhere else. 
    } catch (InvalidKeyException | NoSuchAlgorithmException| NoSuchPaddingException | IllegalBlockSizeException| BadPaddingException e) { 
     e.printStackTrace(); 
     //throw new IOException(e.getMessage()); 
    } 
} 

我知道，它需要一些時間來工作到我的代碼，但我會很感激，如果你能幫助我。

編輯： 關於EncryptionUtil

public static final byte[] encrypt(final SymmetricEncryption enc,final byte[] content,final SecretKey key) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, UnsupportedEncodingException { 
     final Cipher cipher = Cipher.getInstance(enc.toString()); 
     cipher.init(Cipher.ENCRYPT_MODE, key); 
     return cipher.doFinal(content); 
    } 

    public static final byte[] decrypt(final SymmetricEncryption enc,final byte[] text,final SecretKey key) throws IllegalBlockSizeException, BadPaddingException, InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException { 
     final Cipher cipher = Cipher.getInstance(enc.toString()); 
     cipher.init(Cipher.DECRYPT_MODE, key); 
     return cipher.doFinal(text); 
    } 

更多的測試後的代碼我發現這些數據不會被我的樹莓派發送正確的，所以我想在現在的塊發送。

Answer 1

我懷疑你的問題是對in.read的調用沒有讀取整個輸入流。不保證讀取您請求的全部長度。這是相當正常的做法來讀取while循環中輸入流，讀入緩衝區，直到到達流的末尾 - 更像是：

byte[] buffer = new byte[1024]; 
int read; 

while ((read = in.read(buffer)) != -1) { 
    out.write(buffer, 0, read); 
} 
out.flush(); 
out.close(); 

請注意，您現有的代碼不會檢查返回值in.read查看實際讀取的字節數。