add pow

app/src/main/java/com/bitchat/android/MainActivity.kt

@@ -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()

app/src/main/java/com/bitchat/android/nostr/NostrClient.kt

@@ -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)
             

app/src/main/java/com/bitchat/android/nostr/NostrGeohashService.kt

@@ -1156,6 +1156,16 @@ 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)}...")

app/src/main/java/com/bitchat/android/nostr/NostrProofOfWork.kt

@@ -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"
+        }
+    }
+}

app/src/main/java/com/bitchat/android/nostr/NostrProtocol.kt

@@ -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 +121,28 @@ 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=${powSettings.difficulty}")
+            
+            // Mine the event before signing
+            val minedEvent = NostrProofOfWork.mineEvent(
+                event = event,
+                targetDifficulty = powSettings.difficulty,
+                maxIterations = 2_000_000 // Allow up to 2M iterations for reasonable mining time
+            )
+            
+            if (minedEvent != null) {
+                event = minedEvent
+                val actualDifficulty = NostrProofOfWork.calculateDifficulty(event.id)
+                Log.d(TAG, "✅ PoW mining successful: target=${powSettings.difficulty}, actual=$actualDifficulty, nonce=${NostrProofOfWork.getNonce(event)}")
+            } else {
+                Log.w(TAG, "❌ PoW mining failed, proceeding without PoW")
+            }
+        }
+        
+        return@withContext senderIdentity.signEvent(event)
     }
     
     // MARK: - Private Methods

app/src/main/java/com/bitchat/android/nostr/PoWPreferenceManager.kt

@@ -0,0 +1,124 @@
+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 = false
+    private const val DEFAULT_POW_DIFFICULTY = 16 // 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()
+    
+    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)"
+        )
+    }
+}

app/src/main/java/com/bitchat/android/ui/AboutSheet.kt

@@ -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 +171,136 @@ 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)
+                                            ) { 
+                                                Text(
+                                                    text = "$powDifficulty",
+                                                    fontSize = 9.sp,
+                                                    fontFamily = FontFamily.Monospace,
+                                                    color = Color.White,
+                                                    modifier = Modifier.padding(horizontal = 6.dp, vertical = 2.dp)
+                                                )
+                                            }
+                                        }
+                                    }
+                                }
+                            )
+                        }
+                        
+                        Text(
+                            text = "add computational 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..32f,
+                                    steps = 31, // 32 discrete values (0-32)
+                                    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

app/src/main/java/com/bitchat/android/ui/ChatHeader.kt

@@ -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,

app/src/main/java/com/bitchat/android/ui/PoWStatusIndicator.kt

@@ -0,0 +1,205 @@
+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,
+    isMining: Boolean = false,
+    style: PoWIndicatorStyle = PoWIndicatorStyle.COMPACT
+) {
+    val powEnabled by PoWPreferenceManager.powEnabled.collectAsState()
+    val powDifficulty by PoWPreferenceManager.powDifficulty.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)
+                    )
+                }
+                
+                // Difficulty indicator
+                Text(
+                    text = powDifficulty.toString(),
+                    fontSize = 10.sp,
+                    fontFamily = FontFamily.Monospace,
+                    fontWeight = FontWeight.Medium,
+                    color = if (isMining) Color(0xFFFF9500) else {
+                        if (isDark) Color(0xFF32D74B) else Color(0xFF248A3D)
+                    }
+                )
+            }
+        }
+        
+        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)
+                )
+            }
+        }
+    }
+}