how to solve this question?

[happy123654]

hello, every boy, who can help me to resolve this question?

Now, I use my tool to test my java cos. there is a test case failure in T0 protocol and success in T1 or TCL.
the command is as followed:
send: 80050000
the right response: 256 bytes data +SW.
the real response: The tool cannot receive anything.

If I modify the commad as followed:
send:80500000
the right response: 255 bytes data +SW
the real response: ==the right response

[later123654]

hello, you can provide your code here which can help me to parse this question.

[happy123654]

public void process(APDU apdu)
{
if (selectingApplet())
{
return;
}

byte[] buf = apdu.getBuffer();
switch (buf[ISO7816.OFFSET_INS])
{
case (byte)0x01:
Util.arrayFillNonAtomic(buf, (short)0, (short)256, (byte)0xaa);
apdu.setOutgoingAndSend((short)0, (short)256);
break;
case (byte)0x02:
Util.arrayFillNonAtomic(buf, (short)0, (short)256, (byte)0xbb);
apdu.setOutgoingAndSend((short)0, (short)255);
break;
default:
ISOException.throwIt(ISO7816.SW_INS_NOT_SUPPORTED);
}
}

[later123654]

I test the code and the command with JCOP card and the question is still exist.
But the command is ok：
the command( 8005000000) can return 256 bytest data.

so you can modify the command.

[happy123654]

hello boy. I modify my command to be 8005000000 and I can get the right response.

but why?

[later123654]

I guess the reason : the reader handle the command as case 1 and refuse the response data from the card.

[happy123654]

i see and thanks very much!

[BirdKing]

T0 is an imperfect protocol. It claims the applet and host on pc knows how many bytes will be translated. You may add setIncomingAndReceive() and try this apdu again.