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https://github.com/permissionlesstech/bitchat-android.git
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noise
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callebtc
@@ -0,0 +1,349 @@
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package com.bitchat.android.noise
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import android.util.Log
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import java.security.SecureRandom
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/**
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* Individual Noise session for a specific peer - 100% compatible with iOS implementation
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*
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* Represents a single Noise XX protocol session with the following states:
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* - UNINITIALIZED: Session created but handshake not started
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* - HANDSHAKING: Handshake in progress (messages 1, 2, or 3)
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* - ESTABLISHED: Handshake complete, ready for transport encryption
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* - FAILED: Session failed and needs to be recreated
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*/
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class NoiseSession(
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private val peerID: String,
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private val isInitiator: Boolean,
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private val localStaticPrivateKey: ByteArray,
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private val localStaticPublicKey: ByteArray
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) {
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companion object {
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private const val TAG = "NoiseSession"
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// Rekey thresholds (same as iOS)
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private const val REKEY_TIME_LIMIT = 3600000L // 1 hour
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private const val REKEY_MESSAGE_LIMIT = 10000L // 10k messages
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}
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// Session state
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private var state: NoiseSessionState = NoiseSessionState.Uninitialized
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private val creationTime = System.currentTimeMillis()
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// Handshake state (will be replaced with actual Noise implementation)
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private var handshakeStep = 0
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private var handshakeMessages = mutableListOf<ByteArray>()
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// Transport state (after handshake completion)
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private var sendKey: ByteArray? = null
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private var receiveKey: ByteArray? = null
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private var sendNonce = 0L
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private var receiveNonce = 0L
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// Remote peer information
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private var remoteStaticPublicKey: ByteArray? = null
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private var handshakeHash: ByteArray? = null
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// Message counting for rekey
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private var messagesSent = 0L
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private var messagesReceived = 0L
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// MARK: - Session State
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/**
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* Session states matching iOS implementation
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*/
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sealed class NoiseSessionState {
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object Uninitialized : NoiseSessionState()
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object Handshaking : NoiseSessionState()
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object Established : NoiseSessionState()
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data class Failed(val error: Throwable) : NoiseSessionState()
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override fun toString(): String = when (this) {
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is Uninitialized -> "uninitialized"
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is Handshaking -> "handshaking"
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is Established -> "established"
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is Failed -> "failed: ${error.message}"
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}
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}
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fun getState(): NoiseSessionState = state
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fun isEstablished(): Boolean = state is NoiseSessionState.Established
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fun isHandshaking(): Boolean = state is NoiseSessionState.Handshaking
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fun getCreationTime(): Long = creationTime
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// MARK: - Handshake Implementation
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/**
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* Start handshake (initiator only)
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* Returns the first handshake message (32 bytes - ephemeral public key)
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*/
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fun startHandshake(): ByteArray {
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if (!isInitiator) {
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throw IllegalStateException("Only initiator can start handshake")
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}
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if (state != NoiseSessionState.Uninitialized) {
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throw IllegalStateException("Handshake already started")
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}
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state = NoiseSessionState.Handshaking
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handshakeStep = 1
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// TODO: Replace with actual Noise implementation
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// For now, generate a mock 32-byte ephemeral key message
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val ephemeralKey = ByteArray(32)
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SecureRandom().nextBytes(ephemeralKey)
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handshakeMessages.add(ephemeralKey)
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Log.d(TAG, "Started handshake with $peerID (step 1)")
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return ephemeralKey
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}
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/**
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* Process incoming handshake message
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* Returns response message if needed, null if handshake complete
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*/
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fun processHandshakeMessage(message: ByteArray): ByteArray? {
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Log.d(TAG, "Processing handshake message from $peerID (${message.size} bytes)")
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// Initialize if we're a responder receiving the first message
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if (state == NoiseSessionState.Uninitialized && !isInitiator) {
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state = NoiseSessionState.Handshaking
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handshakeStep = 1
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}
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if (state != NoiseSessionState.Handshaking) {
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throw IllegalStateException("Invalid state for handshake message: $state")
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}
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handshakeMessages.add(message)
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// TODO: Replace with actual Noise XX implementation
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// This is a mock implementation that follows the XX pattern steps
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return when (handshakeStep) {
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1 -> {
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// Received first message (e)
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if (isInitiator) {
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throw IllegalStateException("Initiator should not receive first message")
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}
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handshakeStep = 2
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// Generate response message (e, ee, s, es) - mock implementation
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val responseMessage = ByteArray(96) // 32 (e) + 48 (encrypted s) + 16 (tag)
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SecureRandom().nextBytes(responseMessage)
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Log.d(TAG, "Sending handshake response to $peerID (step 2)")
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responseMessage
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}
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2 -> {
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// Received second message (e, ee, s, es)
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if (!isInitiator) {
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throw IllegalStateException("Responder should not receive second message")
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}
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handshakeStep = 3
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// Generate final message (s, se) - mock implementation
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val finalMessage = ByteArray(48) // 48 bytes (encrypted s) + 16 (tag)
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SecureRandom().nextBytes(finalMessage)
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Log.d(TAG, "Sending final handshake message to $peerID (step 3)")
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finalMessage
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}
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3 -> {
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// Received final message (s, se)
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if (isInitiator) {
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throw IllegalStateException("Initiator should not receive third message")
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}
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// Complete handshake
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completeHandshake()
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null // No response needed
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}
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else -> {
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throw IllegalStateException("Invalid handshake step: $handshakeStep")
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}
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}.also {
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// Check if we (as initiator) completed handshake after sending final message
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if (isInitiator && handshakeStep == 3) {
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completeHandshake()
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}
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}
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}
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/**
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* Complete handshake and derive transport keys
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*/
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private fun completeHandshake() {
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Log.d(TAG, "Completing handshake with $peerID")
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// TODO: Replace with actual Noise session split
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// For now, generate mock transport keys
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sendKey = ByteArray(32)
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receiveKey = ByteArray(32)
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remoteStaticPublicKey = ByteArray(32)
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handshakeHash = ByteArray(32)
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SecureRandom().apply {
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nextBytes(sendKey!!)
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nextBytes(receiveKey!!)
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nextBytes(remoteStaticPublicKey!!)
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nextBytes(handshakeHash!!)
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}
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// Reset nonces for transport mode
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sendNonce = 0
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receiveNonce = 0
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state = NoiseSessionState.Established
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Log.d(TAG, "Handshake completed with $peerID")
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}
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// MARK: - Transport Encryption
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/**
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* Encrypt data in transport mode
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*/
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fun encrypt(data: ByteArray): ByteArray {
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if (!isEstablished()) {
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throw IllegalStateException("Session not established")
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}
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// TODO: Replace with actual ChaCha20-Poly1305 encryption
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// For now, return mock encrypted data
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val encryptedData = ByteArray(data.size + 16) // Add 16-byte MAC tag
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System.arraycopy(data, 0, encryptedData, 0, data.size)
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// Fill MAC tag area with mock data
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SecureRandom().nextBytes(encryptedData.sliceArray(data.size until encryptedData.size))
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messagesSent++
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sendNonce++
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return encryptedData
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}
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/**
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* Decrypt data in transport mode
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*/
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fun decrypt(encryptedData: ByteArray): ByteArray {
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if (!isEstablished()) {
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throw IllegalStateException("Session not established")
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}
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if (encryptedData.size < 16) {
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throw IllegalArgumentException("Encrypted data too short")
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}
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// TODO: Replace with actual ChaCha20-Poly1305 decryption
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// For now, return mock decrypted data (remove 16-byte MAC tag)
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val decryptedData = ByteArray(encryptedData.size - 16)
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System.arraycopy(encryptedData, 0, decryptedData, 0, decryptedData.size)
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messagesReceived++
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receiveNonce++
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return decryptedData
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}
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// MARK: - Session Information
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/**
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* Get remote static public key (available after handshake completion)
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*/
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fun getRemoteStaticPublicKey(): ByteArray? {
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return remoteStaticPublicKey?.clone()
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}
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/**
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* Get handshake hash for channel binding
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*/
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fun getHandshakeHash(): ByteArray? {
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return handshakeHash?.clone()
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}
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/**
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* Check if session needs rekeying
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*/
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fun needsRekey(): Boolean {
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if (!isEstablished()) return false
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val timeLimit = System.currentTimeMillis() - creationTime > REKEY_TIME_LIMIT
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val messageLimit = (messagesSent + messagesReceived) > REKEY_MESSAGE_LIMIT
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return timeLimit || messageLimit
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}
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/**
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* Get session statistics
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*/
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fun getSessionStats(): String = buildString {
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appendLine("Session with $peerID:")
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appendLine(" State: $state")
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appendLine(" Role: ${if (isInitiator) "initiator" else "responder"}")
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appendLine(" Handshake step: $handshakeStep")
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appendLine(" Messages sent: $messagesSent")
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appendLine(" Messages received: $messagesReceived")
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appendLine(" Session age: ${(System.currentTimeMillis() - creationTime) / 1000}s")
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appendLine(" Needs rekey: ${needsRekey()}")
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appendLine(" Has remote key: ${remoteStaticPublicKey != null}")
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}
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/**
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* Reset session state
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*/
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fun reset() {
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state = NoiseSessionState.Uninitialized
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handshakeStep = 0
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handshakeMessages.clear()
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sendKey = null
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receiveKey = null
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sendNonce = 0
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receiveNonce = 0
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remoteStaticPublicKey = null
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handshakeHash = null
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messagesSent = 0
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messagesReceived = 0
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}
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/**
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* Clean up session resources
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*/
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fun destroy() {
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try {
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// Clear sensitive keys
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sendKey?.fill(0)
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receiveKey?.fill(0)
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remoteStaticPublicKey?.fill(0)
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handshakeHash?.fill(0)
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// Clear handshake messages
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handshakeMessages.forEach { it.fill(0) }
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handshakeMessages.clear()
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state = NoiseSessionState.Failed(Exception("Session destroyed"))
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} catch (e: Exception) {
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Log.w(TAG, "Error during session cleanup: ${e.message}")
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}
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}
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}
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/**
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* Session-specific errors
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*/
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sealed class SessionError(message: String, cause: Throwable? = null) : Exception(message, cause) {
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object InvalidState : SessionError("Session in invalid state")
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object NotEstablished : SessionError("Session not established")
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object HandshakeFailed : SessionError("Handshake failed")
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object EncryptionFailed : SessionError("Encryption failed")
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object DecryptionFailed : SessionError("Decryption failed")
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}
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