E3HBFdt7

1package com.sudox.protocol.controllers
2
3import com.sudox.cipher.Cipher
4import com.sudox.protocol.ProtocolController
5import java.util.LinkedList
6
7class HandshakeController(val protocolController: ProtocolController) {
8
9    private var ownPublicKey: ByteArray? = null
10    private var ownPrivateKey: ByteArray? = null
11    private var secretKey: ByteArray? = null
12
13    companion object {
14        private val PUBLIC_KEY_PACKET_NAME = "pub".toByteArray()
15    }
16
17    fun startHandshake() {
18        generateOwnKeysPair()
19        protocolController.sendPacket(PUBLIC_KEY_PACKET_NAME, ownPublicKey!!)
20    }
21
22    fun handleIncomingMessage(slices: LinkedList<ByteArray>) {
23        val name = slices.remove()!!
24
25        if (name.contentEquals(PUBLIC_KEY_PACKET_NAME)) {
26            handlePublicKeyMessage(slices)
27        }
28    }
29
30    private fun handlePublicKeyMessage(slices: LinkedList<ByteArray>) {
31        if (slices.size < 2) {
32            closeHandshakeSession()
33            return
34        }
35
36        val serverPublicKey = slices.remove()!!
37        val serverPublicKeySign = slices.remove()!!
38        val serverOkHmac = slices.remove()!!
39
40        // First step - checking server's public key
41        if (!Cipher.verifyMessageWithECDSA(serverPublicKey, serverPublicKeySign)) {
42            closeHandshakeSession()
43            return
44        }
45
46        // Second step - generate secret key ...
47        secretKey = Cipher.calculateSecretKey(ownPrivateKey, serverPublicKey)
48
49        if (secretKey!!.isEmpty()) {
50            closeHandshakeSession()
51            return
52        }
53
54        // Third step - checking secret key using hmac's comparing
55        val okHmac = Cipher.calculateHMAC(secretKey, "ok".toByteArray())
56
57        if (!serverOkHmac.contentEquals(okHmac)) {
58            closeHandshakeSession()
59            return
60        }
61    }
62
63    private fun generateOwnKeysPair() {
64        val keysPairId = Cipher.generateKeysPair()
65
66        ownPublicKey = Cipher.getPublicKey(keysPairId)
67        ownPrivateKey = Cipher.getPrivateKey(keysPairId)
68
69        Cipher.removeKeysPair(keysPairId)
70    }
71
72    private fun closeHandshakeSession() {
73        removeAllKeys()
74        protocolController.closeConnection(true)
75    }
76
77    private fun removeAllKeys() {
78        ownPublicKey = null
79        ownPrivateKey = null
80        secretKey = null
81    }
82}