Nip13 pow (#357)

* add pow * animation * matrix style * animation better * improve animation * improve animation * works * fix jump * difficulty indicator * 10 is default * animation runs forever * pow in message timestamp * pow works * default on * adjust animation * no printing
2026-07-24 23:45:19 +00:00 · 2025-08-31 13:23:22 +02:00
parent 5b62118336
commit b62b15a21f
13 changed files with 1182 additions and 108 deletions
@@ -42,6 +42,7 @@ import com.bitchat.android.ui.ChatViewModel
 import com.bitchat.android.ui.theme.BitchatTheme
 import com.bitchat.android.ui.theme.ThemePreference
 import com.bitchat.android.ui.theme.ThemePreferenceManager
+import com.bitchat.android.nostr.PoWPreferenceManager
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch

@@ -591,6 +592,10 @@ class MainActivity : ComponentActivity() {
                
                Log.d("MainActivity", "Permissions verified, initializing chat system")
                
+                // Initialize PoW preferences early in the initialization process
+                PoWPreferenceManager.init(this@MainActivity)
+                Log.d("MainActivity", "PoW preferences initialized")
+                
                // Ensure all permissions are still granted (user might have revoked in settings)
                if (!permissionManager.areAllPermissionsGranted()) {
                    val missing = permissionManager.getMissingPermissions()
@@ -59,7 +59,8 @@ data class BitchatMessage(
    val channel: String? = null,
    val encryptedContent: ByteArray? = null,
    val isEncrypted: Boolean = false,
-    val deliveryStatus: DeliveryStatus? = null
+    val deliveryStatus: DeliveryStatus? = null,
+    val powDifficulty: Int? = null
 ) : Parcelable {

    /**
@@ -169,7 +169,7 @@ class NostrClient private constructor(private val context: Context) {
                // Derive geohash-specific identity
                val geohashIdentity = NostrIdentityBridge.deriveIdentity(geohash, context)
                
-                // Create ephemeral event
+                // Create ephemeral event (with PoW if enabled)
                val event = NostrProtocol.createEphemeralGeohashEvent(
                    content = content,
                    geohash = geohash,
@@ -281,6 +281,16 @@ class NostrClient private constructor(private val context: Context) {
        handler: (content: String, senderPubkey: String, nickname: String?, timestamp: Int) -> Unit
    ) {
        try {
+            // Check Proof of Work validation for incoming geohash events
+            val powSettings = PoWPreferenceManager.getCurrentSettings()
+            if (powSettings.enabled && powSettings.difficulty > 0) {
+                if (!NostrProofOfWork.validateDifficulty(event, powSettings.difficulty)) {
+                    Log.w(TAG, "🚫 Rejecting geohash event ${event.id.take(8)}... due to insufficient PoW (required: ${powSettings.difficulty})")
+                    return
+                }
+                Log.v(TAG, "✅ PoW validation passed for geohash event ${event.id.take(8)}...")
+            }
+            
            // Extract nickname from tags
            val nickname = event.tags.find { it.size >= 2 && it[0] == "n" }?.get(1)
            
@@ -19,6 +19,7 @@ import kotlinx.coroutines.launch
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 import java.util.*
+import kotlin.random.Random

 /**
 * Service responsible for all Nostr and Geohash business logic extracted from ChatViewModel
@@ -242,6 +243,37 @@ class NostrGeohashService(
    fun sendGeohashMessage(content: String, channel: com.bitchat.android.geohash.GeohashChannel, myPeerID: String, nickname: String?) {
        coroutineScope.launch {
            try {
+                // Generate a temporary message ID for tracking animation
+                val tempMessageId = "temp_${System.currentTimeMillis()}_${Random.nextInt(1000)}"
+                
+                // Add local echo message IMMEDIATELY (with temporary ID)
+                val powSettingsLocal = PoWPreferenceManager.getCurrentSettings()
+                val localMessage = BitchatMessage(
+                    id = tempMessageId,
+                    sender = nickname ?: myPeerID,
+                    content = content,
+                    timestamp = Date(),
+                    isRelay = false,
+                    senderPeerID = "geohash:${channel.geohash}",
+                    channel = "#${channel.geohash}",
+                    powDifficulty = if (powSettingsLocal.enabled) powSettingsLocal.difficulty else null
+                )
+                
+                // Store and display the message immediately
+                storeGeohashMessage(channel.geohash, localMessage)
+                messageManager.addMessage(localMessage)
+                
+                Log.d(TAG, "📝 Added message immediately with temp ID: $tempMessageId")
+                
+                // Check if PoW is enabled before starting animation
+                val powSettings = PoWPreferenceManager.getCurrentSettings()
+                if (powSettings.enabled && powSettings.difficulty > 0) {
+                    // Start matrix animation for this message
+                    com.bitchat.android.ui.PoWMiningTracker.startMiningMessage(tempMessageId)
+                    Log.d(TAG, "🎭 Started matrix animation for message: $tempMessageId")
+                }
+                
+                // Now begin the async PoW process
                val identity = NostrIdentityBridge.deriveIdentity(
                    forGeohash = channel.geohash,
                    context = application
@@ -257,6 +289,12 @@ class NostrGeohashService(
                    teleported = teleported
                )
                
+                // Stop animation when PoW completes
+                if (powSettings.enabled && powSettings.difficulty > 0) {
+                    com.bitchat.android.ui.PoWMiningTracker.stopMiningMessage(tempMessageId)
+                    Log.d(TAG, "🎭 Stopped matrix animation for message: $tempMessageId")
+                }
+                
                val nostrRelayManager = NostrRelayManager.getInstance(application)
                nostrRelayManager.sendEventToGeohash(
                    event = event,
@@ -267,22 +305,10 @@ class NostrGeohashService(
                
                Log.i(TAG, "📤 Sent geohash message to ${channel.geohash}: ${content.take(50)}")
                
-                // Add local echo message
-                val localMessage = BitchatMessage(
-                    sender = nickname ?: myPeerID,
-                    content = content,
-                    timestamp = Date(),
-                    isRelay = false,
-                    senderPeerID = "geohash:${channel.geohash}",
-                    channel = "#${channel.geohash}"
-                )
-                
-                // Store our own message in geohash history 
-                storeGeohashMessage(channel.geohash, localMessage)
-                messageManager.addMessage(localMessage)
-                
            } catch (e: Exception) {
                Log.e(TAG, "Failed to send geohash message: ${e.message}")
+                // Make sure to stop animation even if there's an error
+                com.bitchat.android.ui.PoWMiningTracker.stopMiningMessage("temp_${System.currentTimeMillis()}")
            }
        }
    }
@@ -1156,6 +1182,16 @@ class NostrGeohashService(
                return@launch
            }
            
+            // Check Proof of Work validation BEFORE other processing
+            val powSettings = PoWPreferenceManager.getCurrentSettings()
+            if (powSettings.enabled && powSettings.difficulty > 0) {
+                if (!NostrProofOfWork.validateDifficulty(event, powSettings.difficulty)) {
+                    Log.w(TAG, "🚫 Rejecting geohash event ${event.id.take(8)}... due to insufficient PoW (required: ${powSettings.difficulty})")
+                    return@launch
+                }
+                Log.v(TAG, "✅ PoW validation passed for event ${event.id.take(8)}...")
+            }
+            
            // Check if this user is blocked in geohash channels BEFORE any processing
            if (isGeohashUserBlocked(event.pubkey)) {
                Log.v(TAG, "🚫 Skipping event from blocked geohash user: ${event.pubkey.take(8)}...")
@@ -1238,6 +1274,9 @@ class NostrGeohashService(
            // Note: mentions parsing needs peer nicknames parameter
            // val mentions = messageManager.parseMentions(content, peerNicknames, nickname)
            
+            // Calculate actual PoW difficulty from the finalized event ID so we can show it for incoming messages too
+            val actualPow = try { NostrProofOfWork.calculateDifficulty(event.id) } catch (e: Exception) { 0 }
+
            val message = BitchatMessage(
                id = event.id,
                sender = senderName,
@@ -1247,7 +1286,8 @@ class NostrGeohashService(
                originalSender = senderHandle,
                senderPeerID = "nostr:${event.pubkey.take(8)}",
                mentions = null, // mentions need to be passed from outside
-                channel = "#$geohash"
+                channel = "#$geohash",
+                powDifficulty = actualPow.takeIf { it > 0 }
            )
            
            // Store in geohash history for persistence across channel switches
@@ -0,0 +1,216 @@
+package com.bitchat.android.nostr
+
+import android.util.Log
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import java.security.MessageDigest
+import kotlin.random.Random
+
+/**
+ * Nostr Proof of Work (PoW) implementation following NIP-13
+ * 
+ * This implements the Proof of Work system for Nostr events to provide spam deterrence.
+ * The difficulty is defined as the number of leading zero bits in the event ID.
+ * 
+ * Reference: https://github.com/nostr-protocol/nips/blob/master/13.md
+ */
+object NostrProofOfWork {
+    
+    private const val TAG = "NostrProofOfWork"
+    
+    /**
+     * Calculate the difficulty (number of leading zero bits) of an event ID
+     * @param eventIdHex The hexadecimal event ID
+     * @return The number of leading zero bits
+     */
+    fun calculateDifficulty(eventIdHex: String): Int {
+        var count = 0
+        
+        for (i in eventIdHex.indices) {
+            val nibble = eventIdHex[i].toString().toInt(16)
+            if (nibble == 0) {
+                count += 4
+            } else {
+                // Count leading zeros in the nibble
+                count += when (nibble) {
+                    1 -> 3  // 0001
+                    2, 3 -> 2  // 001x
+                    4, 5, 6, 7 -> 1  // 01xx
+                    else -> 0  // 1xxx
+                }
+                break
+            }
+        }
+        
+        return count
+    }
+    
+    /**
+     * Validate that an event meets the minimum difficulty requirement
+     * @param event The Nostr event to validate
+     * @param minimumDifficulty The minimum required difficulty
+     * @return true if the event meets the difficulty requirement
+     */
+    fun validateDifficulty(event: NostrEvent, minimumDifficulty: Int): Boolean {
+        if (minimumDifficulty <= 0) return true
+        
+        val actualDifficulty = calculateDifficulty(event.id)
+        val committedDifficulty = getCommittedDifficulty(event)
+        
+        Log.d(TAG, "Validating PoW: actual=$actualDifficulty, required=$minimumDifficulty, committed=$committedDifficulty")
+        
+        // Check if actual difficulty meets requirement
+        if (actualDifficulty < minimumDifficulty) {
+            Log.w(TAG, "Event ${event.id.take(16)}... has insufficient difficulty: $actualDifficulty < $minimumDifficulty")
+            return false
+        }
+        
+        // If there's a committed difficulty, it should match or exceed the minimum
+        if (committedDifficulty != null && committedDifficulty < minimumDifficulty) {
+            Log.w(TAG, "Event ${event.id.take(16)}... has committed difficulty $committedDifficulty but achieved $actualDifficulty (possible spam)")
+            return false
+        }
+        
+        return true
+    }
+    
+    /**
+     * Mine a Nostr event to achieve the target difficulty
+     * @param event The event to mine (will be modified with nonce tag)
+     * @param targetDifficulty The target difficulty to achieve
+     * @param maxIterations Maximum number of iterations before giving up (default: 1,000,000)
+     * @return The mined event with nonce tag, or null if mining failed
+     */
+    suspend fun mineEvent(
+        event: NostrEvent,
+        targetDifficulty: Int,
+        maxIterations: Int = 1_000_000
+    ): NostrEvent? = withContext(Dispatchers.Default) {
+        if (targetDifficulty <= 0) return@withContext event
+        
+        Log.d(TAG, "Starting PoW mining for difficulty $targetDifficulty...")
+        val startTime = System.currentTimeMillis()
+        
+        var nonce = Random.nextLong(0, 1_000_000).toString()
+        var iterations = 0
+        
+        while (iterations < maxIterations) {
+            // Create a copy of the event with the nonce tag
+            val eventWithNonce = addNonceTag(event, nonce, targetDifficulty)
+            
+            // Calculate the event ID
+            val eventId = eventWithNonce.computeEventIdHex()
+            val actualDifficulty = calculateDifficulty(eventId)
+            
+            if (actualDifficulty >= targetDifficulty) {
+                val timeElapsed = System.currentTimeMillis() - startTime
+                Log.i(TAG, "✅ PoW mining successful! Difficulty: $actualDifficulty, iterations: $iterations, time: ${timeElapsed}ms")
+                
+                // Return the event with the computed ID
+                return@withContext eventWithNonce.copy(id = eventId)
+            }
+            
+            // Increment nonce and try again
+            nonce = (nonce.toLongOrNull()?.plus(1) ?: Random.nextLong()).toString()
+            iterations++
+            
+            // Log progress every 100,000 iterations
+            if (iterations % 100_000 == 0) {
+                val timeElapsed = System.currentTimeMillis() - startTime
+                Log.d(TAG, "PoW mining progress: $iterations iterations, ${timeElapsed}ms elapsed")
+            }
+        }
+        
+        val timeElapsed = System.currentTimeMillis() - startTime
+        Log.w(TAG, "❌ PoW mining failed after $maxIterations iterations (${timeElapsed}ms)")
+        return@withContext null
+    }
+    
+    /**
+     * Add or update the nonce tag in an event
+     * @param event The original event
+     * @param nonce The nonce value
+     * @param targetDifficulty The target difficulty being attempted
+     * @return A new event with the nonce tag added/updated
+     */
+    private fun addNonceTag(event: NostrEvent, nonce: String, targetDifficulty: Int): NostrEvent {
+        val newTags = event.tags.toMutableList()
+        
+        // Remove existing nonce tag if present
+        newTags.removeAll { tag -> tag.isNotEmpty() && tag[0] == "nonce" }
+        
+        // Add new nonce tag with format: ["nonce", nonce_value, target_difficulty]
+        newTags.add(listOf("nonce", nonce, targetDifficulty.toString()))
+        
+        // Update created_at as recommended by NIP-13
+        val updatedCreatedAt = (System.currentTimeMillis() / 1000).toInt()
+        
+        return event.copy(
+            tags = newTags,
+            createdAt = updatedCreatedAt
+        )
+    }
+    
+    /**
+     * Get the committed difficulty from an event's nonce tag
+     * @param event The event to check
+     * @return The committed difficulty, or null if not present
+     */
+    private fun getCommittedDifficulty(event: NostrEvent): Int? {
+        val nonceTag = event.tags.find { tag -> 
+            tag.isNotEmpty() && tag[0] == "nonce" && tag.size >= 3 
+        }
+        
+        return nonceTag?.get(2)?.toIntOrNull()
+    }
+    
+    /**
+     * Check if an event has a nonce tag (indicating it was mined)
+     * @param event The event to check
+     * @return true if the event has a nonce tag
+     */
+    fun hasNonce(event: NostrEvent): Boolean {
+        return event.tags.any { tag -> tag.isNotEmpty() && tag[0] == "nonce" }
+    }
+    
+    /**
+     * Get the nonce value from an event
+     * @param event The event to check
+     * @return The nonce value, or null if not present
+     */
+    fun getNonce(event: NostrEvent): String? {
+        val nonceTag = event.tags.find { tag -> 
+            tag.isNotEmpty() && tag[0] == "nonce" && tag.size >= 2 
+        }
+        
+        return nonceTag?.get(1)
+    }
+    
+    /**
+     * Estimate the computational work required for a given difficulty
+     * @param difficulty The target difficulty
+     * @return Estimated number of hash operations required
+     */
+    fun estimateWork(difficulty: Int): Long {
+        return if (difficulty <= 0) 1L else 1L shl difficulty
+    }
+    
+    /**
+     * Get a human-readable description of the estimated mining time
+     * @param difficulty The target difficulty
+     * @param hashesPerSecond Estimated hashes per second (default: 100,000)
+     * @return Human-readable time estimate
+     */
+    fun estimateMiningTime(difficulty: Int, hashesPerSecond: Int = 100_000): String {
+        val estimatedHashes = estimateWork(difficulty)
+        val estimatedSeconds = estimatedHashes / hashesPerSecond
+        
+        return when {
+            estimatedSeconds < 1 -> "< 1 second"
+            estimatedSeconds < 60 -> "${estimatedSeconds}s"
+            estimatedSeconds < 3600 -> "${estimatedSeconds / 60}m ${estimatedSeconds % 60}s"
+            estimatedSeconds < 86400 -> "${estimatedSeconds / 3600}h ${(estimatedSeconds % 3600) / 60}m"
+            else -> "${estimatedSeconds / 86400}d ${(estimatedSeconds % 86400) / 3600}h"
+        }
+    }
+}
@@ -3,6 +3,8 @@ package com.bitchat.android.nostr
 import android.util.Log
 import com.google.gson.Gson
 import com.google.gson.JsonParser
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext

 /**
 * NIP-17 Protocol Implementation for Private Direct Messages
@@ -90,14 +92,15 @@ object NostrProtocol {
    
    /**
     * Create a geohash-scoped ephemeral public message (kind 20000)
+     * Includes Proof of Work mining if enabled in settings
     */
-    fun createEphemeralGeohashEvent(
+    suspend fun createEphemeralGeohashEvent(
        content: String,
        geohash: String,
        senderIdentity: NostrIdentity,
        nickname: String? = null,
        teleported: Boolean = false
-    ): NostrEvent {
+    ): NostrEvent = withContext(Dispatchers.Default) {
        val tags = mutableListOf<List<String>>()
        tags.add(listOf("g", geohash))
        
@@ -110,7 +113,7 @@ object NostrProtocol {
            tags.add(listOf("t", "teleport"))
        }
        
-        val event = NostrEvent(
+        var event = NostrEvent(
            pubkey = senderIdentity.publicKeyHex,
            createdAt = (System.currentTimeMillis() / 1000).toInt(),
            kind = NostrKind.EPHEMERAL_EVENT,
@@ -118,7 +121,36 @@ object NostrProtocol {
            content = content
        )
        
-        return senderIdentity.signEvent(event)
+        // Check if Proof of Work is enabled
+        val powSettings = PoWPreferenceManager.getCurrentSettings()
+        if (powSettings.enabled && powSettings.difficulty > 0) {
+            Log.d(TAG, "PoW enabled for geohash event: difficulty=${powSettings.difficulty}")
+            
+            try {
+                // Start mining state for animated indicators
+                PoWPreferenceManager.startMining()
+                
+                // Mine the event before signing
+                val minedEvent = NostrProofOfWork.mineEvent(
+                    event = event,
+                    targetDifficulty = powSettings.difficulty,
+                    maxIterations = 2_000_000 // Allow up to 2M iterations for reasonable mining time
+                )
+                
+                if (minedEvent != null) {
+                    event = minedEvent
+                    val actualDifficulty = NostrProofOfWork.calculateDifficulty(event.id)
+                    Log.d(TAG, "✅ PoW mining successful: target=${powSettings.difficulty}, actual=$actualDifficulty, nonce=${NostrProofOfWork.getNonce(event)}")
+                } else {
+                    Log.w(TAG, "❌ PoW mining failed, proceeding without PoW")
+                }
+            } finally {
+                // Always stop mining state when done (success or failure)
+                PoWPreferenceManager.stopMining()
+            }
+        }
+        
+        return@withContext senderIdentity.signEvent(event)
    }
    
    // MARK: - Private Methods
@@ -0,0 +1,149 @@
+package com.bitchat.android.nostr
+
+import android.content.Context
+import android.content.SharedPreferences
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+
+/**
+ * Manages Proof of Work preferences for Nostr events
+ */
+object PoWPreferenceManager {
+    
+    private const val PREFS_NAME = "pow_preferences"
+    private const val KEY_POW_ENABLED = "pow_enabled"
+    private const val KEY_POW_DIFFICULTY = "pow_difficulty"
+    
+    // Default values
+    private const val DEFAULT_POW_ENABLED = true
+    private const val DEFAULT_POW_DIFFICULTY = 10 // Reasonable default for geohash spam prevention
+    
+    // State flows for reactive UI
+    private val _powEnabled = MutableStateFlow(DEFAULT_POW_ENABLED)
+    val powEnabled: StateFlow<Boolean> = _powEnabled.asStateFlow()
+    
+    private val _powDifficulty = MutableStateFlow(DEFAULT_POW_DIFFICULTY)
+    val powDifficulty: StateFlow<Int> = _powDifficulty.asStateFlow()
+    
+    // Mining state for animated indicators
+    private val _isMining = MutableStateFlow(false)
+    val isMining: StateFlow<Boolean> = _isMining.asStateFlow()
+    
+    private lateinit var sharedPrefs: SharedPreferences
+    private var isInitialized = false
+    
+    /**
+     * Initialize the preference manager with application context
+     * Should be called once during app startup
+     */
+    fun init(context: Context) {
+        if (isInitialized) return
+        
+        sharedPrefs = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE)
+        
+        // Load current values
+        _powEnabled.value = sharedPrefs.getBoolean(KEY_POW_ENABLED, DEFAULT_POW_ENABLED)
+        _powDifficulty.value = sharedPrefs.getInt(KEY_POW_DIFFICULTY, DEFAULT_POW_DIFFICULTY)
+        
+        isInitialized = true
+    }
+    
+    /**
+     * Get current PoW enabled state
+     */
+    fun isPowEnabled(): Boolean {
+        return _powEnabled.value
+    }
+    
+    /**
+     * Set PoW enabled state
+     */
+    fun setPowEnabled(enabled: Boolean) {
+        _powEnabled.value = enabled
+        if (::sharedPrefs.isInitialized) {
+            sharedPrefs.edit().putBoolean(KEY_POW_ENABLED, enabled).apply()
+        }
+    }
+    
+    /**
+     * Get current PoW difficulty setting
+     */
+    fun getPowDifficulty(): Int {
+        return _powDifficulty.value
+    }
+    
+    /**
+     * Set PoW difficulty (clamped between 0 and 32)
+     */
+    fun setPowDifficulty(difficulty: Int) {
+        val clampedDifficulty = difficulty.coerceIn(0, 32)
+        _powDifficulty.value = clampedDifficulty
+        if (::sharedPrefs.isInitialized) {
+            sharedPrefs.edit().putInt(KEY_POW_DIFFICULTY, clampedDifficulty).apply()
+        }
+    }
+    
+    /**
+     * Get current settings as a data class
+     */
+    data class PoWSettings(
+        val enabled: Boolean,
+        val difficulty: Int
+    )
+    
+    /**
+     * Get current settings
+     */
+    fun getCurrentSettings(): PoWSettings {
+        return PoWSettings(
+            enabled = _powEnabled.value,
+            difficulty = _powDifficulty.value
+        )
+    }
+    
+    /**
+     * Reset to default settings
+     */
+    fun resetToDefaults() {
+        setPowEnabled(DEFAULT_POW_ENABLED)
+        setPowDifficulty(DEFAULT_POW_DIFFICULTY)
+    }
+    
+    /**
+     * Get difficulty levels with descriptions for UI
+     */
+    fun getDifficultyLevels(): List<Pair<Int, String>> {
+        return listOf(
+            0 to "Disabled (no PoW)",
+            8 to "Very Low (instant)",
+            12 to "Low (~0.1s)",
+            16 to "Medium (~2s)",
+            20 to "High (~30s)",
+            24 to "Very High (~8m)",
+            28 to "Extreme (~2h)",
+            32 to "Maximum (~8h)"
+        )
+    }
+    
+    /**
+     * Get current mining state
+     */
+    fun isMining(): Boolean {
+        return _isMining.value
+    }
+    
+    /**
+     * Start mining state - triggers animated indicators
+     */
+    fun startMining() {
+        _isMining.value = true
+    }
+    
+    /**
+     * Stop mining state - stops animated indicators
+     */
+    fun stopMining() {
+        _isMining.value = false
+    }
+}
@@ -7,6 +7,7 @@ import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Bluetooth
 import androidx.compose.material.icons.filled.Lock
 import androidx.compose.material.icons.filled.Public
+import androidx.compose.material.icons.filled.Security
 import androidx.compose.material.icons.filled.Warning
 import androidx.compose.material3.*
 import androidx.compose.runtime.*
@@ -20,6 +21,8 @@ import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.BaselineShift
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
+import com.bitchat.android.nostr.NostrProofOfWork
+import com.bitchat.android.nostr.PoWPreferenceManager

 /**
 * About Sheet for bitchat app information
@@ -168,6 +171,128 @@ fun AboutSheet(
                    }
                }

+                // Proof of Work section
+                item {
+                    val context = LocalContext.current
+                    
+                    // Initialize PoW preferences if not already done
+                    LaunchedEffect(Unit) {
+                        PoWPreferenceManager.init(context)
+                    }
+                    
+                    val powEnabled by PoWPreferenceManager.powEnabled.collectAsState()
+                    val powDifficulty by PoWPreferenceManager.powDifficulty.collectAsState()
+                    
+                    Column(
+                        modifier = Modifier.fillMaxWidth(),
+                        verticalArrangement = Arrangement.spacedBy(8.dp)
+                    ) {
+                        Text(
+                            text = "proof of work",
+                            fontSize = 12.sp,
+                            fontFamily = FontFamily.Monospace,
+                            fontWeight = FontWeight.Medium,
+                            color = colorScheme.onSurface.copy(alpha = 0.8f)
+                        )
+                        
+                        Row(
+                            horizontalArrangement = Arrangement.spacedBy(8.dp),
+                            verticalAlignment = Alignment.CenterVertically
+                        ) {
+                            FilterChip(
+                                selected = !powEnabled,
+                                onClick = { PoWPreferenceManager.setPowEnabled(false) },
+                                label = { Text("pow off", fontFamily = FontFamily.Monospace) }
+                            )
+                            FilterChip(
+                                selected = powEnabled,
+                                onClick = { PoWPreferenceManager.setPowEnabled(true) },
+                                label = { 
+                                    Row(
+                                        horizontalArrangement = Arrangement.spacedBy(6.dp),
+                                        verticalAlignment = Alignment.CenterVertically
+                                    ) {
+                                        Text("pow on", fontFamily = FontFamily.Monospace)
+                                        // Show current difficulty
+                                        if (powEnabled) {
+                                            Surface(
+                                                color = if (isDark) Color(0xFF32D74B) else Color(0xFF248A3D),
+                                                shape = RoundedCornerShape(50)
+                                            ) { Box(Modifier.size(8.dp)) }
+                                        }
+                                    }
+                                }
+                            )
+                        }
+                        
+                        Text(
+                            text = "add proof of work to geohash messages for spam deterrence.",
+                            fontSize = 10.sp,
+                            fontFamily = FontFamily.Monospace,
+                            color = colorScheme.onSurface.copy(alpha = 0.6f)
+                        )
+                        
+                        // Show difficulty slider when enabled
+                        if (powEnabled) {
+                            Column(
+                                modifier = Modifier.fillMaxWidth(),
+                                verticalArrangement = Arrangement.spacedBy(8.dp)
+                            ) {
+                                Text(
+                                    text = "difficulty: $powDifficulty bits (~${NostrProofOfWork.estimateMiningTime(powDifficulty)})",
+                                    fontSize = 11.sp,
+                                    fontFamily = FontFamily.Monospace,
+                                    color = colorScheme.onSurface.copy(alpha = 0.7f)
+                                )
+                                
+                                Slider(
+                                    value = powDifficulty.toFloat(),
+                                    onValueChange = { PoWPreferenceManager.setPowDifficulty(it.toInt()) },
+                                    valueRange = 0f..20f,
+                                    steps = 21, // 20 discrete values (0-20)
+                                    colors = SliderDefaults.colors(
+                                        thumbColor = if (isDark) Color(0xFF32D74B) else Color(0xFF248A3D),
+                                        activeTrackColor = if (isDark) Color(0xFF32D74B) else Color(0xFF248A3D)
+                                    )
+                                )
+                                
+                                // Show difficulty description
+                                Surface(
+                                    modifier = Modifier.fillMaxWidth(),
+                                    color = colorScheme.surfaceVariant.copy(alpha = 0.25f),
+                                    shape = RoundedCornerShape(8.dp)
+                                ) {
+                                    Column(
+                                        modifier = Modifier.padding(12.dp),
+                                        verticalArrangement = Arrangement.spacedBy(4.dp)
+                                    ) {
+                                        Text(
+                                            text = "difficulty $powDifficulty requires ~${NostrProofOfWork.estimateWork(powDifficulty)} hash attempts",
+                                            fontSize = 10.sp,
+                                            fontFamily = FontFamily.Monospace,
+                                            color = colorScheme.onSurface.copy(alpha = 0.7f)
+                                        )
+                                        Text(
+                                            text = when {
+                                                powDifficulty == 0 -> "no proof of work required"
+                                                powDifficulty <= 8 -> "very low - minimal spam protection"
+                                                powDifficulty <= 12 -> "low - basic spam protection"
+                                                powDifficulty <= 16 -> "medium - good spam protection"
+                                                powDifficulty <= 20 -> "high - strong spam protection"
+                                                powDifficulty <= 24 -> "very high - may cause delays"
+                                                else -> "extreme - significant computation required"
+                                            },
+                                            fontSize = 10.sp,
+                                            fontFamily = FontFamily.Monospace,
+                                            color = colorScheme.onSurface.copy(alpha = 0.6f)
+                                        )
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+
                // Network (Tor) section
                item {
                    val ctx = LocalContext.current
@@ -572,6 +572,12 @@ private fun MainHeader(
            // Tor status cable icon when Tor is enabled
            TorStatusIcon(modifier = Modifier.size(14.dp))
            
+            // PoW status indicator
+            PoWStatusIndicator(
+                modifier = Modifier,
+                style = PoWIndicatorStyle.COMPACT
+            )
+
            PeerCounter(
                connectedPeers = connectedPeers.filter { it != viewModel.meshService.myPeerID },
                joinedChannels = joinedChannels,
@@ -117,11 +117,18 @@ fun formatMessageAsAnnotatedString(
        appendIOSFormattedContent(builder, message.content, message.mentions, currentUserNickname, baseColor, isSelf, isDark)
        
        // iOS-style timestamp at the END (smaller, grey)
+        // Timestamp (and optional PoW badge)
        builder.pushStyle(SpanStyle(
            color = Color.Gray.copy(alpha = 0.7f),
            fontSize = (BASE_FONT_SIZE - 4).sp
        ))
        builder.append(" [${timeFormatter.format(message.timestamp)}]")
+        // If message has valid PoW difficulty, append bits immediately after timestamp with minimal spacing
+        //message.powDifficulty?.let { bits ->
+        //    if (bits > 0) {
+        //        builder.append(" ${bits}b")
+        //    }
+        //}
        builder.pop()
        
    } else {
@@ -0,0 +1,270 @@
+package com.bitchat.android.ui
+
+import androidx.compose.material3.*
+import androidx.compose.runtime.*
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.text.font.FontFamily
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.launch
+import kotlin.random.Random
+
+/**
+ * Animation state for individual characters
+ */
+private enum class CharacterAnimationState {
+    ENCRYPTED,    // Showing random encrypted characters
+    DECRYPTING,   // Transitioning to final character
+    FINAL         // Showing final decrypted character
+}
+
+/**
+ * Check if a message should be animated based on its mining state
+ */
+@Composable
+fun shouldAnimateMessage(messageId: String): Boolean {
+    val miningMessages by PoWMiningTracker.miningMessages.collectAsState()
+    return miningMessages.contains(messageId)
+}
+
+/**
+ * Tracks which messages are currently being mined for PoW
+ * Provides reactive state for UI animations
+ */
+object PoWMiningTracker {
+    private val _miningMessages = MutableStateFlow<Set<String>>(emptySet())
+    val miningMessages: StateFlow<Set<String>> = _miningMessages.asStateFlow()
+    
+    /**
+     * Start tracking a message as mining
+     */
+    fun startMiningMessage(messageId: String) {
+        _miningMessages.value = _miningMessages.value + messageId
+    }
+    
+    /**
+     * Stop tracking a message as mining
+     */
+    fun stopMiningMessage(messageId: String) {
+        _miningMessages.value = _miningMessages.value - messageId
+    }
+    
+    /**
+     * Check if a message is currently mining
+     */
+    fun isMiningMessage(messageId: String): Boolean {
+        return _miningMessages.value.contains(messageId)
+    }
+    
+    /**
+     * Clear all mining messages (for cleanup)
+     */
+    fun clearAllMining() {
+        _miningMessages.value = emptySet()
+    }
+}
+
+/**
+ * Enhanced message display that shows matrix animation during PoW mining
+ * Formats message like a normal message but animates only the content portion
+ */
+@Composable
+fun MessageWithMatrixAnimation(
+    message: com.bitchat.android.model.BitchatMessage,
+    currentUserNickname: String,
+    meshService: com.bitchat.android.mesh.BluetoothMeshService,
+    colorScheme: androidx.compose.material3.ColorScheme,
+    timeFormatter: java.text.SimpleDateFormat,
+    onNicknameClick: ((String) -> Unit)?,
+    onMessageLongPress: ((com.bitchat.android.model.BitchatMessage) -> Unit)?,
+    modifier: Modifier = Modifier
+) {
+    val isAnimating = shouldAnimateMessage(message.id)
+    
+    if (isAnimating) {
+        // During animation: Show formatted message with animated content
+        AnimatedMessageDisplay(
+            message = message,
+            currentUserNickname = currentUserNickname,
+            meshService = meshService,
+            colorScheme = colorScheme,
+            timeFormatter = timeFormatter,
+            modifier = modifier
+        )
+    } else {
+        // After animation: Show complete normal message using existing formatter
+        val annotatedText = formatMessageAsAnnotatedString(
+            message = message,
+            currentUserNickname = currentUserNickname,
+            meshService = meshService,
+            colorScheme = colorScheme,
+            timeFormatter = timeFormatter
+        )
+        
+        Text(
+            text = annotatedText,
+            modifier = modifier,
+            fontFamily = FontFamily.Monospace,
+            softWrap = true
+        )
+    }
+}
+
+/**
+ * Display message with proper formatting but animated content
+ * Uses IDENTICAL layout structure as normal message for pixel-perfect alignment
+ */
+@Composable
+private fun AnimatedMessageDisplay(
+    message: com.bitchat.android.model.BitchatMessage,
+    currentUserNickname: String,
+    meshService: com.bitchat.android.mesh.BluetoothMeshService,
+    colorScheme: androidx.compose.material3.ColorScheme,
+    timeFormatter: java.text.SimpleDateFormat,
+    modifier: Modifier = Modifier
+) {
+    // Get the animated content text
+    var animatedContent by remember(message.content) { mutableStateOf(message.content) }
+    val isAnimating = shouldAnimateMessage(message.id)
+    
+    // Character-by-character animation state like the JavaScript version
+    var characterStates by remember(message.content) { 
+        mutableStateOf(message.content.map { char -> 
+            if (char == ' ') CharacterAnimationState.FINAL else CharacterAnimationState.ENCRYPTED 
+        })
+    }
+    
+    // Update animated content when animation state changes
+    LaunchedEffect(isAnimating, message.content) {
+        if (isAnimating && message.content.isNotEmpty()) {
+            val encryptedChars = "!@$%^&*()_+-=[]{}|;:,<>?".toCharArray()
+            
+            // Start character animations with staggered delays (like JS version)
+            message.content.forEachIndexed { index, targetChar ->
+                if (targetChar != ' ') { // Skip spaces
+                    launch {
+                        delay(index * 50L) // Stagger start like JS version
+                        
+                        // Animate this character indefinitely in a loop
+                        while (true) {
+                            // Animate with random characters
+                            while (characterStates.getOrNull(index) == CharacterAnimationState.ENCRYPTED) {
+                                // Generate random encrypted character for this position
+                                val newContent = animatedContent.toCharArray()
+                                if (index < newContent.size) {
+                                    newContent[index] = encryptedChars[Random.nextInt(encryptedChars.size)]
+                                    animatedContent = String(newContent)
+                                }
+                                
+                                delay(100L) // Change character every 100ms like JS
+                                
+                                // Random chance to reveal (10% like JS version)
+                                if (Random.nextFloat() < 0.1f) {
+                                    // Reveal the final character
+                                    val finalContent = animatedContent.toCharArray()
+                                    if (index < finalContent.size) {
+                                        finalContent[index] = targetChar
+                                        animatedContent = String(finalContent)
+                                    }
+                                    
+                                    // Mark as revealed
+                                    val finalStates = characterStates.toMutableList()
+                                    finalStates[index] = CharacterAnimationState.FINAL
+                                    characterStates = finalStates
+                                    break
+                                }
+                            }
+                            
+                            // Keep revealed for 2 seconds, then fade back to encrypted (like JS)
+                            delay(2000L)
+                            
+                            // Reset back to encrypted for next cycle
+                            val resetStates = characterStates.toMutableList()
+                            resetStates[index] = CharacterAnimationState.ENCRYPTED
+                            characterStates = resetStates
+                        }
+                    }
+                }
+            }
+        } else {
+            // Not animating, show final content
+            animatedContent = message.content
+            characterStates = message.content.map { CharacterAnimationState.FINAL }
+        }
+    }
+    
+    // Create a temporary message with animated content for formatting
+    val animatedMessage = message.copy(content = animatedContent)
+    
+    // Use formatting function without timestamp during animation
+    val annotatedText = if (isAnimating) {
+        formatMessageAsAnnotatedStringWithoutTimestamp(
+            message = animatedMessage,
+            currentUserNickname = currentUserNickname,
+            meshService = meshService,
+            colorScheme = colorScheme
+        )
+    } else {
+        formatMessageAsAnnotatedString(
+            message = animatedMessage,
+            currentUserNickname = currentUserNickname,
+            meshService = meshService,
+            colorScheme = colorScheme,
+            timeFormatter = timeFormatter
+        )
+    }
+    
+    // Use IDENTICAL Text composable structure as normal message
+    Text(
+        text = annotatedText,
+        modifier = modifier,
+        fontFamily = FontFamily.Monospace,
+        softWrap = true,
+        overflow = androidx.compose.ui.text.style.TextOverflow.Visible,
+        style = androidx.compose.ui.text.TextStyle(
+            color = colorScheme.onSurface
+        )
+    )
+}
+
+
+/**
+ * Format message without timestamp and PoW badge for animation phase
+ * Identical to formatMessageAsAnnotatedString but excludes timestamp and PoW badge
+ */
+private fun formatMessageAsAnnotatedStringWithoutTimestamp(
+    message: com.bitchat.android.model.BitchatMessage,
+    currentUserNickname: String,
+    meshService: com.bitchat.android.mesh.BluetoothMeshService,
+    colorScheme: androidx.compose.material3.ColorScheme
+): AnnotatedString {
+    // Get the full formatted text first
+    val timeFormatter = java.text.SimpleDateFormat("HH:mm:ss", java.util.Locale.getDefault())
+    val fullText = formatMessageAsAnnotatedString(
+        message = message,
+        currentUserNickname = currentUserNickname,
+        meshService = meshService,
+        colorScheme = colorScheme,
+        timeFormatter = timeFormatter
+    )
+    
+    // Find and remove the timestamp and PoW badge at the end
+    val text = fullText.text
+    val timestampPattern = """ \[\d{2}:\d{2}:\d{2}].*$""".toRegex() // Matches " [HH:mm:ss] 12b" or just " [HH:mm:ss]"
+    val match = timestampPattern.find(text)
+    
+    return if (match != null) {
+        // Remove timestamp and PoW portion
+        val endIndex = match.range.first
+        AnnotatedString(
+            text = text.substring(0, endIndex),
+            spanStyles = fullText.spanStyles.filter { it.end <= endIndex },
+            paragraphStyles = fullText.paragraphStyles.filter { it.end <= endIndex }
+        )
+    } else {
+        fullText
+    }
+}
@@ -166,101 +166,120 @@ private fun MessageTextWithClickableNicknames(
    onMessageLongPress: ((BitchatMessage) -> Unit)?,
    modifier: Modifier = Modifier
 ) {
-    val annotatedText = formatMessageAsAnnotatedString(
-        message = message,
-        currentUserNickname = currentUserNickname,
-        meshService = meshService,
-        colorScheme = colorScheme,
-        timeFormatter = timeFormatter
-    )
+    // Check if this message should be animated during PoW mining
+    val shouldAnimate = shouldAnimateMessage(message.id)
    
-    // Check if this message was sent by self to avoid click interactions on own nickname
-    val isSelf = message.senderPeerID == meshService.myPeerID || 
-                 message.sender == currentUserNickname ||
-                 message.sender.startsWith("$currentUserNickname#")
+    // If animation is needed, use the matrix animation component for content only
+    if (shouldAnimate) {
+        // Display message with matrix animation for content
+        MessageWithMatrixAnimation(
+            message = message,
+            currentUserNickname = currentUserNickname,
+            meshService = meshService,
+            colorScheme = colorScheme,
+            timeFormatter = timeFormatter,
+            onNicknameClick = onNicknameClick,
+            onMessageLongPress = onMessageLongPress,
+            modifier = modifier
+        )
+    } else {
+        // Normal message display
+        val annotatedText = formatMessageAsAnnotatedString(
+            message = message,
+            currentUserNickname = currentUserNickname,
+            meshService = meshService,
+            colorScheme = colorScheme,
+            timeFormatter = timeFormatter
+        )
        
-    val haptic = LocalHapticFeedback.current
-    val context = LocalContext.current
-    var textLayoutResult by remember { mutableStateOf<TextLayoutResult?>(null) }
-    Text(
-        text = annotatedText,
-        modifier = modifier.pointerInput(message) {
-            detectTapGestures(
-                onTap = { position ->
-                    val layout = textLayoutResult ?: return@detectTapGestures
-                    val offset = layout.getOffsetForPosition(position)
-                    // Nickname click only when not self
-                    if (!isSelf && onNicknameClick != null) {
-                        val nicknameAnnotations = annotatedText.getStringAnnotations(
-                            tag = "nickname_click",
+        // Check if this message was sent by self to avoid click interactions on own nickname
+        val isSelf = message.senderPeerID == meshService.myPeerID || 
+                     message.sender == currentUserNickname ||
+                     message.sender.startsWith("$currentUserNickname#")
+        
+        val haptic = LocalHapticFeedback.current
+        val context = LocalContext.current
+        var textLayoutResult by remember { mutableStateOf<TextLayoutResult?>(null) }
+        Text(
+            text = annotatedText,
+            modifier = modifier.pointerInput(message) {
+                detectTapGestures(
+                    onTap = { position ->
+                        val layout = textLayoutResult ?: return@detectTapGestures
+                        val offset = layout.getOffsetForPosition(position)
+                        // Nickname click only when not self
+                        if (!isSelf && onNicknameClick != null) {
+                            val nicknameAnnotations = annotatedText.getStringAnnotations(
+                                tag = "nickname_click",
+                                start = offset,
+                                end = offset
+                            )
+                            if (nicknameAnnotations.isNotEmpty()) {
+                                val nickname = nicknameAnnotations.first().item
+                                haptic.performHapticFeedback(HapticFeedbackType.TextHandleMove)
+                                onNicknameClick.invoke(nickname)
+                                return@detectTapGestures
+                            }
+                        }
+                        // Geohash teleport (all messages)
+                        val geohashAnnotations = annotatedText.getStringAnnotations(
+                            tag = "geohash_click",
                            start = offset,
                            end = offset
                        )
-                        if (nicknameAnnotations.isNotEmpty()) {
-                            val nickname = nicknameAnnotations.first().item
+                        if (geohashAnnotations.isNotEmpty()) {
+                            val geohash = geohashAnnotations.first().item
+                            try {
+                                val locationManager = com.bitchat.android.geohash.LocationChannelManager.getInstance(
+                                    context
+                                )
+                                val level = when (geohash.length) {
+                                    in 0..2 -> com.bitchat.android.geohash.GeohashChannelLevel.REGION
+                                    in 3..4 -> com.bitchat.android.geohash.GeohashChannelLevel.PROVINCE
+                                    5 -> com.bitchat.android.geohash.GeohashChannelLevel.CITY
+                                    6 -> com.bitchat.android.geohash.GeohashChannelLevel.NEIGHBORHOOD
+                                    else -> com.bitchat.android.geohash.GeohashChannelLevel.BLOCK
+                                }
+                                val channel = com.bitchat.android.geohash.GeohashChannel(level, geohash.lowercase())
+                                locationManager.setTeleported(true)
+                                locationManager.select(com.bitchat.android.geohash.ChannelID.Location(channel))
+                            } catch (_: Exception) { }
                            haptic.performHapticFeedback(HapticFeedbackType.TextHandleMove)
-                            onNicknameClick.invoke(nickname)
                            return@detectTapGestures
                        }
+                        // URL open (all messages)
+                        val urlAnnotations = annotatedText.getStringAnnotations(
+                            tag = "url_click",
+                            start = offset,
+                            end = offset
+                        )
+                        if (urlAnnotations.isNotEmpty()) {
+                            val raw = urlAnnotations.first().item
+                            val resolved = if (raw.startsWith("http://", ignoreCase = true) || raw.startsWith("https://", ignoreCase = true)) raw else "https://$raw"
+                            try {
+                                val intent = Intent(Intent.ACTION_VIEW, Uri.parse(resolved))
+                                intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+                                context.startActivity(intent)
+                            } catch (_: Exception) { }
+                            haptic.performHapticFeedback(HapticFeedbackType.TextHandleMove)
+                            return@detectTapGestures
+                        }
+                    },
+                    onLongPress = {
+                        haptic.performHapticFeedback(HapticFeedbackType.LongPress)
+                        onMessageLongPress?.invoke(message)
                    }
-                    // Geohash teleport (all messages)
-                    val geohashAnnotations = annotatedText.getStringAnnotations(
-                        tag = "geohash_click",
-                        start = offset,
-                        end = offset
-                    )
-                    if (geohashAnnotations.isNotEmpty()) {
-                        val geohash = geohashAnnotations.first().item
-                        try {
-                            val locationManager = com.bitchat.android.geohash.LocationChannelManager.getInstance(
-                                context
-                            )
-                            val level = when (geohash.length) {
-                                in 0..2 -> com.bitchat.android.geohash.GeohashChannelLevel.REGION
-                                in 3..4 -> com.bitchat.android.geohash.GeohashChannelLevel.PROVINCE
-                                5 -> com.bitchat.android.geohash.GeohashChannelLevel.CITY
-                                6 -> com.bitchat.android.geohash.GeohashChannelLevel.NEIGHBORHOOD
-                                else -> com.bitchat.android.geohash.GeohashChannelLevel.BLOCK
-                            }
-                            val channel = com.bitchat.android.geohash.GeohashChannel(level, geohash.lowercase())
-                            locationManager.setTeleported(true)
-                            locationManager.select(com.bitchat.android.geohash.ChannelID.Location(channel))
-                        } catch (_: Exception) { }
-                        haptic.performHapticFeedback(HapticFeedbackType.TextHandleMove)
-                        return@detectTapGestures
-                    }
-                    // URL open (all messages)
-                    val urlAnnotations = annotatedText.getStringAnnotations(
-                        tag = "url_click",
-                        start = offset,
-                        end = offset
-                    )
-                    if (urlAnnotations.isNotEmpty()) {
-                        val raw = urlAnnotations.first().item
-                        val resolved = if (raw.startsWith("http://", ignoreCase = true) || raw.startsWith("https://", ignoreCase = true)) raw else "https://$raw"
-                        try {
-                            val intent = Intent(Intent.ACTION_VIEW, Uri.parse(resolved))
-                            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
-                            context.startActivity(intent)
-                        } catch (_: Exception) { }
-                        haptic.performHapticFeedback(HapticFeedbackType.TextHandleMove)
-                        return@detectTapGestures
-                    }
-                },
-                onLongPress = {
-                    haptic.performHapticFeedback(HapticFeedbackType.LongPress)
-                    onMessageLongPress?.invoke(message)
-                }
-            )
-        },
-        fontFamily = FontFamily.Monospace,
-        softWrap = true,
-        overflow = TextOverflow.Visible,
-        style = androidx.compose.ui.text.TextStyle(
-            color = colorScheme.onSurface
-        ),
-        onTextLayout = { result -> textLayoutResult = result }
-    )
+                )
+            },
+            fontFamily = FontFamily.Monospace,
+            softWrap = true,
+            overflow = TextOverflow.Visible,
+            style = androidx.compose.ui.text.TextStyle(
+                color = colorScheme.onSurface
+            ),
+            onTextLayout = { result -> textLayoutResult = result }
+        )
+    }
 }

@Composable
@@ -0,0 +1,194 @@
+package com.bitchat.android.ui
+
+import androidx.compose.animation.core.*
+import androidx.compose.foundation.layout.*
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Security
+import androidx.compose.material3.*
+import androidx.compose.runtime.*
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.text.font.FontFamily
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import com.bitchat.android.nostr.NostrProofOfWork
+import com.bitchat.android.nostr.PoWPreferenceManager
+
+/**
+ * Shows the current Proof of Work status and settings
+ */
+@Composable
+fun PoWStatusIndicator(
+    modifier: Modifier = Modifier,
+    style: PoWIndicatorStyle = PoWIndicatorStyle.COMPACT
+) {
+    val powEnabled by PoWPreferenceManager.powEnabled.collectAsState()
+    val powDifficulty by PoWPreferenceManager.powDifficulty.collectAsState()
+    val isMining by PoWPreferenceManager.isMining.collectAsState()
+    val colorScheme = MaterialTheme.colorScheme
+    val isDark = colorScheme.background.red + colorScheme.background.green + colorScheme.background.blue < 1.5f
+    
+    if (!powEnabled) return
+    
+    when (style) {
+        PoWIndicatorStyle.COMPACT -> {
+            Row(
+                modifier = modifier,
+                horizontalArrangement = Arrangement.spacedBy(4.dp),
+                verticalAlignment = Alignment.CenterVertically
+            ) {
+                // PoW icon with animation if mining
+                if (isMining) {
+                    val rotation by rememberInfiniteTransition(label = "pow-rotation").animateFloat(
+                        initialValue = 0f,
+                        targetValue = 360f,
+                        animationSpec = infiniteRepeatable(
+                            animation = tween(1000, easing = LinearEasing),
+                            repeatMode = RepeatMode.Restart
+                        ),
+                        label = "pow-icon-rotation"
+                    )
+                    
+                    Icon(
+                        imageVector = Icons.Filled.Security,
+                        contentDescription = "Mining PoW",
+                        tint = Color(0xFFFF9500), // Orange for mining
+                        modifier = Modifier
+                            .size(12.dp)
+                            .graphicsLayer { rotationZ = rotation }
+                    )
+                } else {
+                    Icon(
+                        imageVector = Icons.Filled.Security,
+                        contentDescription = "PoW Enabled",
+                        tint = if (isDark) Color(0xFF32D74B) else Color(0xFF248A3D), // Green when ready
+                        modifier = Modifier.size(12.dp)
+                    )
+                }
+            }
+        }
+        
+        PoWIndicatorStyle.DETAILED -> {
+            Surface(
+                modifier = modifier,
+                color = colorScheme.surfaceVariant.copy(alpha = 0.3f),
+                shape = androidx.compose.foundation.shape.RoundedCornerShape(8.dp)
+            ) {
+                Row(
+                    modifier = Modifier.padding(horizontal = 8.dp, vertical = 4.dp),
+                    horizontalArrangement = Arrangement.spacedBy(6.dp),
+                    verticalAlignment = Alignment.CenterVertically
+                ) {
+                    // PoW icon
+                    Icon(
+                        imageVector = Icons.Filled.Security,
+                        contentDescription = "Proof of Work",
+                        tint = if (isMining) Color(0xFFFF9500) else {
+                            if (isDark) Color(0xFF32D74B) else Color(0xFF248A3D)
+                        },
+                        modifier = Modifier.size(14.dp)
+                    )
+                    
+                    // Status text
+                    Text(
+                        text = if (isMining) {
+                            "mining..."
+                        } else {
+                            "pow: ${powDifficulty}bit"
+                        },
+                        fontSize = 11.sp,
+                        fontFamily = FontFamily.Monospace,
+                        color = if (isMining) Color(0xFFFF9500) else {
+                            colorScheme.onSurface.copy(alpha = 0.7f)
+                        }
+                    )
+                    
+                    // Time estimate
+                    if (!isMining && powDifficulty > 0) {
+                        Text(
+                            text = "(~${NostrProofOfWork.estimateMiningTime(powDifficulty)})",
+                            fontSize = 9.sp,
+                            fontFamily = FontFamily.Monospace,
+                            color = colorScheme.onSurface.copy(alpha = 0.5f)
+                        )
+                    }
+                }
+            }
+        }
+    }
+}
+
+/**
+ * Style options for the PoW status indicator
+ */
+enum class PoWIndicatorStyle {
+    COMPACT,    // Small icon + difficulty number
+    DETAILED    // Icon + status text + time estimate
+}
+
+/**
+ * Shows mining progress with animated indicator
+ */
+@Composable
+fun PoWMiningIndicator(
+    modifier: Modifier = Modifier,
+    difficulty: Int,
+    iterations: Int? = null
+) {
+    val colorScheme = MaterialTheme.colorScheme
+    
+    Surface(
+        modifier = modifier,
+        color = Color(0xFFFF9500).copy(alpha = 0.1f),
+        shape = androidx.compose.foundation.shape.RoundedCornerShape(8.dp)
+    ) {
+        Row(
+            modifier = Modifier.padding(horizontal = 12.dp, vertical = 8.dp),
+            horizontalArrangement = Arrangement.spacedBy(8.dp),
+            verticalAlignment = Alignment.CenterVertically
+        ) {
+            // Animated security icon
+            val rotation by rememberInfiniteTransition(label = "mining-rotation").animateFloat(
+                initialValue = 0f,
+                targetValue = 360f,
+                animationSpec = infiniteRepeatable(
+                    animation = tween(1000, easing = LinearEasing),
+                    repeatMode = RepeatMode.Restart
+                ),
+                label = "mining-icon-rotation"
+            )
+            
+            Icon(
+                imageVector = Icons.Filled.Security,
+                contentDescription = "Mining Proof of Work",
+                tint = Color(0xFFFF9500),
+                modifier = Modifier
+                    .size(16.dp)
+                    .graphicsLayer { rotationZ = rotation }
+            )
+            
+            Column(
+                verticalArrangement = Arrangement.spacedBy(2.dp)
+            ) {
+                Text(
+                    text = "mining proof of work...",
+                    fontSize = 12.sp,
+                    fontFamily = FontFamily.Monospace,
+                    fontWeight = FontWeight.Medium,
+                    color = Color(0xFFFF9500)
+                )
+                
+                Text(
+                    text = "difficulty: ${difficulty}bit (~${NostrProofOfWork.estimateMiningTime(difficulty)})" +
+                            if (iterations != null) " • ${iterations} attempts" else "",
+                    fontSize = 10.sp,
+                    fontFamily = FontFamily.Monospace,
+                    color = colorScheme.onSurface.copy(alpha = 0.7f)
+                )
+            }
+        }
+    }
+}