javacard

I want to send an APDU with a length of 1699 bytes via NFC (class IsoDep ) to a Java Card smartcard. I get the error java.io.IOException: Transceive length exceeds supported maximum My phone is a Samsung Galaxy S7. I use extended-length in my applet on the card. I have verified that the card supports extended length. I tested this via pyapdutool by sending an APDU with 4000 bytes to the card. I found that when I write this code, the result is false : final Tag t = (Tag) tag; myTag = IsoDep.get(t); boolean result = myTag.isExtendedLengthApduSupported(); I have this in my manifest: <activity

I have a ACR38 samrt-card-reader and a number of Javacard [2.1.1] compliant with GP Spec [02]. As I know, there is two kind of APDU, Short-APDU [APDU with LC or/and LE shorter than 255 ] and Extended-APDU [APDU with LC or/and LE greater than 255 ]. is that right? We send Short-APDU in T=0 protocol and send Extended-APDU in T=1 protocol. is that right? I sent Short-APDU to my card successfully. [via GPJ , GPShell , OpenSC-Tool ]. And now, I want to know: 1: if I want to use Extended APDU, my card must support it? or my Reader must support it? or both!? or all the cards and all the readers

I'm new to the whole topic of Java Card and tried to look at a few code examples to get a better understanding. I found a sample for AES usage in the oracle forum but have a few problems with the following part: private void doAES(APDU apdu) { byte b[] = apdu.getBuffer(); short incomingLength = (short) (apdu.setIncomingAndReceive()); if (incomingLength != 24) ISOException.throwIt(ISO7816.SW_WRONG_LENGTH); //perform encryption and append results in APDU Buffer a[] automatically cipherAES.init(aesKey, Cipher.MODE_ENCRYPT); cipherAES.doFinal(b, (short) dataOffset, incomingLength, a, (short)

I want to write my applet in a way that its APDU commands and status words wasn't be clear in the transmission channel between my card and my reader. I mean I don't want to send APDU commands and responses to be plain text for third parties. I think I have two option : After selecting my applet on the card, for all the other commands, do an encryption function on the data section of APDU commands and decrypt them on the card and after that analyze them. Note that I can't encrypt whole the command using this methodology because the result may have conflict with another SELECT APDU command and

I want to optimize SHA-3 algorithm on a Java Card. I need a fast algorithm consuming less memory which allows to easy convert byte[] to short[] (or short [] to byte[] ). My current implementation looks like this: private short[] byteToShort(byte[] b,int len) { short len_conv = (short)(len/2); for ( short x = 0; x < len_conv;x++) { for ( short j = 0 ; j < 2 ; j++) aux[j] = b[2*x+j]; temp_conv[x] = (short)((((short)aux[1]) & 0xFF) | ((((short)(aux[0]) & 0xFF) << 8 ))); } return temp_conv; } where len is actual size of the b array and aux and temp_conv are defined as private and allocated as :