Full Code of darconeous/gauss-key-card for AI

Repository: darconeous/gauss-key-card
Branch: master
Commit: 5555081e4871
Files: 7
Total size: 26.3 KB

Directory structure:
gitextract_tdvdpbfu/

├── .gitignore
├── .gitmodules
├── LICENSE
├── README.md
├── build.xml
└── src/
    └── io/
        └── github/
            └── darconeous/
                └── gausskeycard/
                    ├── ECP256.java
                    └── GaussKeyCard.java

================================================
FILE CONTENTS
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================================================
FILE: .gitignore
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.DS_Store
/bin/


================================================
FILE: .gitmodules
================================================
[submodule "ext/ant"]
	path = ext/ant
	url = https://github.com/martinpaljak/ant-javacard.git


================================================
FILE: LICENSE
================================================

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================================================
FILE: README.md
================================================
Gauss Key Card
==============

*Gauss Key Card* is a [Java Card][] applet that implements the minimal
working subset of the [Tesla Key Card Protocol][]. Supported Java Card
implementations that load this application will be able to be paired
with a compatible vehicle and subsequently unlock, start, or lock the
vehicle in the same way you would with an official key card. ([video][])

If at this point you can't imagine why you might ever want to use this
applet, then it is not for you.

[Java Card]: https://en.wikipedia.org/wiki/Java_Card
[Tesla Key Card Protocol]: https://gist.github.com/darconeous/2cd2de11148e3a75685940158bddf933
[video]: https://www.youtube.com/watch?v=QBP_Hjlpwjs

## Caveats ##

THIS APPLET IS INTENDED FOR EXPERIMENTAL USE ONLY. IT HAS NOT BEEN
REVIEWED, CHECKED, APPROVED, OR ENDORSED BY TESLA. IT MAY BE BLOCKED
BY TESLA AT ANY TIME.

BY USING THIS APPLET (OR INSTALLING IT TO A CARD FOR SOMEONE ELSE
TO USE) YOU ASSUME ALL RESPONSIBILITY, RISK, AND LIABILITY FOR THE
USE OR MISUSE OF THIS SOFTWARE. SEE [LICENSE AGREEMENT](./LICENSE)
FOR MORE INFORMATION.

There are some serious caveats that need to be well understood before
using this applet:

### Type-A vs. Type-B ###

ISO/IEC 14443 defines two types of contactless devices: Type-A and Type-B.
There are javacards available in both varieties, and this applet will
blissfully allow itself to be installed onto either type. However, *Tesla
vehicles currently ignore type-B cards*, so make sure that your card is
indeed a 14443 type-A card.

### Maximum Frame Size ###

The maximum frame size (FSC) for the card must be 96 bytes or greater.
This corresponds to a FSCI value of 6 or greater. **Any card with an FSCI
of 5 or less will not work**.

Tesla vehicles will ignore the FSCI field of the ATS, which means that it
will not attempt to break up larger frames if the indicated FSCI is small (<6).
Specifically, **the card MUST be able to properly handle receiving the
authenticate APDU (86 bytes) in a single frame**. If a card advertises
an FSCI smaller than 6 then it is unlikely to be able to satisfy this
requirement.

For example, smart cards with DESFire EV1 emulation support have an
FSCI of 5, and will unfortunately choke if they receive a frame larger
than 64 bytes. Such cards are not able to be used as Tesla Key Cards.

> NOTE: In earlier versions of this document, this behavior was confused with
> the NFC UID length. It just happened to be the case that most of the
> 4-byte UID cards the author tested also had an FCI of 5. There is no
> limitation of the length of the UID on the card imposed by the vehicle.

A list of tested cards can be found [here](https://github.com/darconeous/gauss-key-card/wiki/Recommended-Cards).

### Software updates could make this applet useless ###

Official Tesla Key Cards have an attestation certificate, which means
that Tesla could easily block non-Tesla key cards from pairing with
vehicles at any point in the future via a software update. Keys
already paired with a vehicle *might* continue to work in such a
scenario, but there are no guarantees.

Since there is no publicly available comprehensive documentation for
the Tesla Key Card Protocol, what is known was determined through
observing the interactions between the vehicle and an official Tesla
Key Card. Gauss Key Card supports all commands that are currently
being used by the vehicle during pairing and authentication, but there
are several additional commands that are not supported because there
was not enough context to infer what their purpose might be. If Tesla
at some point enables additional functionality or features which
require those commands, existing Gauss Key Cards would be unable to
participate.

### Updating GaussKeyCard Applet Will Break Pairing

If you decide to upgrade the version of GaussKeyCard on your card
to a new version, the pairing will be broken because a new internal
private key will be generated for the card.

## Security ##

To increase the difficulty of cloning, the private value of the ECDH
key pair is generated on-card when the applet is installed and never
leaves the secure element. No mechanism for externally supplying a
private key with a known value is provided by this implementation.

Avoid buying Tesla Key Cards from anyone other than Tesla---the card
may be have weak or known private keys. Authentic Tesla Key Cards
should be safe to buy or use from anyone, but until the vehicle
actually verifies attestation certificates there is no way to be sure.
Until then you should always assume that whoever sold you a key card
might also have the ability to unlock and start any vehicle you
subsequently pair with the card.

## Smartcard Requirements ##

 * Java Card 2.2.2 (or later)
 * Contactless ISO/IEC 14443 **Type-A** interface (NFC)
 * **FSCI must be 6 or larger.** (Must support frame sizes of at least 96 bytes)
 * Must support [`KeyAgreement.ALG_EC_SVDP_DH`][]
 * Must support [`Cipher.ALG_AES_BLOCK_128_ECB_NOPAD`][]
 * [Known card management keys][], so you can actually load the applet

[`KeyAgreement.ALG_EC_SVDP_DH`]: https://docs.oracle.com/javacard/3.0.5/api/javacard/security/KeyAgreement.html#ALG_EC_SVDP_DH
[`Cipher.ALG_AES_BLOCK_128_ECB_NOPAD`]: https://docs.oracle.com/javacard/3.0.5/api/javacardx/crypto/Cipher.html#ALG_AES_BLOCK_128_ECB_NOPAD
[Known card management keys]: https://github.com/martinpaljak/GlobalPlatformPro/wiki/Keys

A list of tested cards can be found [here](https://github.com/darconeous/gauss-key-card/wiki/Recommended-Cards).

## Installing/Uninstalling ##

You can download a pre-built CAP file on the [project release page][];

[project release page]: https://github.com/darconeous/gauss-key-card/releases

To install the applet to a supported Java Card *with default card
management keys*, use [GlobalPlatformPro](https://github.com/martinpaljak/GlobalPlatformPro):

```
$ gp -install bin/GaussKeyCard.cap
```

Uninstalling is similar:

```
$ gp -uninstall bin/GaussKeyCard.cap
```

## Building ##

1. Install `ant`.
   * macOS/homebrew: Run `brew install ant`
2. Run `git submodule init`
3. Run `git submodule update --recursive`
4. Run `ant`


================================================
FILE: build.xml
================================================
<?xml version="1.0" encoding="UTF-8"?>
<project name="Gauss Key Card Applet" default="dist" basedir=".">
  <description>Builds the project.</description>

  <target name="dist" description="generate the distribution">
    <tstamp/>
    <get src="https://github.com/martinpaljak/ant-javacard/releases/download/18.09.25/ant-javacard.jar" dest="ext/ant/" skipexisting="true"/>
	<!-- <ant dir="ext/ant"/> -->
    <!-- Create the distribution directory -->
    <taskdef name="javacard" classname="pro.javacard.ant.JavaCard" classpath="ext/ant/ant-javacard.jar"/>
    <javacard jckit="ext/ant/sdks/jc222_kit/">
      <cap aid="F465736C614C6F67696330303258" output="bin/GaussKeyCard.cap" sources="src" classes="bin" version="1.1">
        <applet class="io.github.darconeous.gausskeycard.GaussKeyCard" aid="F465736C614C6F6769633030325801"/>
      </cap>
    </javacard>
  </target>

  <target name="clean" description="clean up">
    <!-- Delete the built applet -->
    <delete dir="bin"/>
  </target>

</project>


================================================
FILE: src/io/github/darconeous/gausskeycard/ECP256.java
================================================
package io.github.darconeous.gausskeycard;

import javacard.security.ECKey;
import javacard.security.ECPrivateKey;
import javacard.security.ECPublicKey;
import javacard.security.KeyBuilder;
import javacard.security.KeyPair;

/** Class for creating NIST P-256 keys. */
public class ECP256 {
	public static final short PRIVATE_KEY_LENGTH = 256;

	public static final byte[] p = {
	    (byte)0xff, (byte)0xff, (byte)0xff, (byte)0xff, (byte)0x0,
	    (byte)0x0, (byte)0x0, (byte)0x1, (byte)0x0, (byte)0x0, (byte)0x0,
	    (byte)0x0, (byte)0x0, (byte)0x0, (byte)0x0, (byte)0x0, (byte)0x0,
	    (byte)0x0, (byte)0x0, (byte)0x0, (byte)0xff, (byte)0xff, (byte)0xff,
	    (byte)0xff, (byte)0xff, (byte)0xff, (byte)0xff, (byte)0xff,
	    (byte)0xff, (byte)0xff, (byte)0xff, (byte)0xff
	};

	public static final byte[] a = {
	    (byte)0xff, (byte)0xff, (byte)0xff, (byte)0xff, (byte)0x0,
	    (byte)0x0, (byte)0x0, (byte)0x1, (byte)0x0, (byte)0x0, (byte)0x0,
	    (byte)0x0, (byte)0x0, (byte)0x0, (byte)0x0, (byte)0x0, (byte)0x0,
	    (byte)0x0, (byte)0x0, (byte)0x0, (byte)0xff, (byte)0xff, (byte)0xff,
	    (byte)0xff, (byte)0xff, (byte)0xff, (byte)0xff, (byte)0xff,
	    (byte)0xff, (byte)0xff, (byte)0xff, (byte)0xfc
	};

	public static final byte[] b = {
	    (byte)0x5a, (byte)0xc6, (byte)0x35, (byte)0xd8, (byte)0xaa,
	    (byte)0x3a, (byte)0x93, (byte)0xe7, (byte)0xb3, (byte)0xeb,
	    (byte)0xbd, (byte)0x55, (byte)0x76, (byte)0x98, (byte)0x86,
	    (byte)0xbc, (byte)0x65, (byte)0x1d, (byte)0x6, (byte)0xb0,
	    (byte)0xcc, (byte)0x53, (byte)0xb0, (byte)0xf6, (byte)0x3b,
	    (byte)0xce, (byte)0x3c, (byte)0x3e, (byte)0x27, (byte)0xd2,
	    (byte)0x60, (byte)0x4b
	};

	public static final byte[] r = {
	    (byte)0xFF, (byte)0xFF, (byte)0xFF, (byte)0xFF, (byte)0x00,
	    (byte)0x00, (byte)0x00, (byte)0x00, (byte)0xFF, (byte)0xFF,
	    (byte)0xFF, (byte)0xFF, (byte)0xFF, (byte)0xFF, (byte)0xFF,
	    (byte)0xFF, (byte)0xBC, (byte)0xE6, (byte)0xFA, (byte)0xAD,
	    (byte)0xA7, (byte)0x17, (byte)0x9E, (byte)0x84, (byte)0xF3,
	    (byte)0xB9, (byte)0xCA, (byte)0xC2, (byte)0xFC, (byte)0x63,
	    (byte)0x25, (byte)0x51
	};

	public static final byte[] g = {
	    (byte)0x4, (byte)0x6b, (byte)0x17, (byte)0xd1, (byte)0xf2,
	    (byte)0xe1, (byte)0x2c, (byte)0x42, (byte)0x47, (byte)0xf8,
	    (byte)0xbc, (byte)0xe6, (byte)0xe5, (byte)0x63, (byte)0xa4,
	    (byte)0x40, (byte)0xf2, (byte)0x77, (byte)0x3, (byte)0x7d,
	    (byte)0x81, (byte)0x2d, (byte)0xeb, (byte)0x33, (byte)0xa0,
	    (byte)0xf4, (byte)0xa1, (byte)0x39, (byte)0x45, (byte)0xd8,
	    (byte)0x98, (byte)0xc2, (byte)0x96, (byte)0x4f, (byte)0xe3,
	    (byte)0x42, (byte)0xe2, (byte)0xfe, (byte)0x1a, (byte)0x7f,
	    (byte)0x9b, (byte)0x8e, (byte)0xe7, (byte)0xeb, (byte)0x4a,
	    (byte)0x7c, (byte)0xf, (byte)0x9e, (byte)0x16, (byte)0x2b,
	    (byte)0xce, (byte)0x33, (byte)0x57, (byte)0x6b, (byte)0x31,
	    (byte)0x5e, (byte)0xce, (byte)0xcb, (byte)0xb6, (byte)0x40,
	    (byte)0x68, (byte)0x37, (byte)0xbf, (byte)0x51, (byte)0xf5
	};

	public static void setCurveParameters(ECKey eckey) {
		eckey.setFieldFP(p, (short)0, (short)(p.length));
		eckey.setA(a, (short)0, (short)(a.length));
		eckey.setB(b, (short)0, (short)(b.length));
		eckey.setG(g, (short)0, (short)(g.length));
		eckey.setR(r, (short)0, (short)(r.length));
	}

	public static KeyPair newKeyPair(boolean keyEncryption) {
		final ECPrivateKey ecPriv;
		final ECPublicKey ecPub;

		ecPriv = (ECPrivateKey)KeyBuilder.buildKey(
			KeyBuilder.TYPE_EC_FP_PRIVATE,
			PRIVATE_KEY_LENGTH,
			keyEncryption
		);

		ecPub = (ECPublicKey)KeyBuilder.buildKey(
			KeyBuilder.TYPE_EC_FP_PUBLIC,
			PRIVATE_KEY_LENGTH,
			keyEncryption
		);

		ECP256.setCurveParameters(ecPriv);
		ECP256.setCurveParameters(ecPub);

		return new KeyPair(ecPub, ecPriv);
	}
}


================================================
FILE: src/io/github/darconeous/gausskeycard/GaussKeyCard.java
================================================
package io.github.darconeous.gausskeycard;

import javacard.framework.APDU;
import javacard.framework.Applet;
import javacard.framework.ISO7816;
import javacard.framework.ISOException;
import javacard.security.AESKey;
import javacard.security.CryptoException;
import javacard.security.ECPrivateKey;
import javacard.security.ECPublicKey;
import javacard.security.KeyAgreement;
import javacard.security.KeyBuilder;
import javacard.security.KeyPair;
import javacard.security.RandomData;
import javacardx.crypto.Cipher;

public class GaussKeyCard extends Applet
{
	/* Card commands we support. */
	private static final byte INS_GET_PUBLIC_KEY = (byte)0x04;
	private static final byte INS_AUTHENTICATE = (byte)0x11;
	private static final byte INS_GET_CARD_INFO = (byte)0x14;

	private static final short OFFSET_CHALLENGE = (short)(ISO7816.OFFSET_CDATA + 65);

	// Constants from JavaCard 3.x. This way we can still install on
	// JC 2.2.2 cards and fall back to the traditional behavior.
	private static final byte TYPE_AES_TRANSIENT_DESELECT = 14;
	private static final byte TYPE_AES_TRANSIENT_RESET = 13;

	private final KeyPair key1;
	private final KeyAgreement ecdh;
	private final Cipher aes_ecb;
	private final AESKey aes_key;
	private final RandomData rng;

	public static void
	install(byte[] info, short off, byte len)
	{
		final GaussKeyCard applet = new GaussKeyCard();
		applet.register();
	}

	protected
	GaussKeyCard()
	{
		key1 = ECP256.newKeyPair(false);

		key1.genKeyPair();

		ecdh = KeyAgreement.getInstance(KeyAgreement.ALG_EC_SVDP_DH, false);

		ecdh.init(key1.getPrivate());

		aes_ecb = Cipher.getInstance(Cipher.ALG_AES_BLOCK_128_ECB_NOPAD, false);

		AESKey key = null;

		try {
			// Put the AES key in RAM if we can.
			key = (AESKey)KeyBuilder.buildKey(TYPE_AES_TRANSIENT_DESELECT, KeyBuilder.LENGTH_AES_128, false);
		} catch (CryptoException e) {
			try {
				// This will use a bit more RAM, but
				// at least it isn't using flash.
				key = (AESKey)KeyBuilder.buildKey(TYPE_AES_TRANSIENT_RESET, KeyBuilder.LENGTH_AES_128, false);
			} catch (CryptoException x) {
				// Uggh. This will wear out the flash
				// eventually, but we don't have a better option.
				key = (AESKey)KeyBuilder.buildKey(KeyBuilder.TYPE_AES, KeyBuilder.LENGTH_AES_128, false);
			}
		}

		aes_key = key;

		// We shouldn't require high-strength random numbers
		// for calculating the challenge salt.
		rng = RandomData.getInstance(RandomData.ALG_PSEUDO_RANDOM);
	}

	public void
	process(APDU apdu)
	{
		final byte[] buffer = apdu.getBuffer();

		if (selectingApplet()) {
			return;
		}

		// We only support the proprietary class.
		if ((buffer[ISO7816.OFFSET_CLA] & (byte)0x80) != (byte)0x80) {
			ISOException.throwIt(ISO7816.SW_CLA_NOT_SUPPORTED);
			return;
		}

		switch (buffer[ISO7816.OFFSET_INS]) {
		case INS_GET_PUBLIC_KEY:
			processGetPublicKey(apdu);
			break;

		case INS_AUTHENTICATE:
			processAuthenticate(apdu);
			break;

		case INS_GET_CARD_INFO:
			processGetCardInfo(apdu);
			break;

		default:
			ISOException.throwIt(ISO7816.SW_INS_NOT_SUPPORTED);
		}
	}

	private void
	processGetCardInfo(APDU apdu)
	{
		final byte[] buffer = apdu.getBuffer();
		final short le = apdu.setOutgoing();

		short len = 0;
		buffer[len++] = 0x00;
		buffer[len++] = 0x01;

		len = le > 0 ? (le > len ? len : le) : len;
		apdu.setOutgoingLength(len);
		apdu.sendBytes((short)0, len);
	}

	private void
	processGetPublicKey(APDU apdu)
	{
		final byte[] buffer = apdu.getBuffer();

		final short le = apdu.setOutgoing();

		final ECPublicKey epubk = (ECPublicKey)key1.getPublic();

		short len = epubk.getW(buffer, (short)0);

		len = le > 0 ? (le > len ? len : le) : len;
		apdu.setOutgoingLength(len);
		apdu.sendBytes((short)0, len);
	}

	private void
	processAuthenticate(APDU apdu)
	{
		final byte[] buffer = apdu.getBuffer();
		final short incomingLength = (short) (buffer[ISO7816.OFFSET_LC] & 0x00FF);

		if (incomingLength < (short)0x51) {
			ISOException.throwIt(ISO7816.SW_WRONG_LENGTH);
		}

		ecdh.generateSecret(buffer, ISO7816.OFFSET_CDATA, (short)65, buffer, (short)16);

		aes_key.setKey(buffer, (short)16);
		aes_ecb.init(aes_key, Cipher.MODE_ENCRYPT);

		// Generate the random salt.
		rng.generateData(buffer, OFFSET_CHALLENGE, (short)4);

		short len = aes_ecb.doFinal(buffer, OFFSET_CHALLENGE, (short)16, buffer, (short)0);
		final short le = apdu.setOutgoing();

		len = le > 0 ? (le > len ? len : le) : len;
		apdu.setOutgoingLength(len);
		apdu.sendBytes((short)0, len);
	}
}