Feat/dm 2byte tlv

CHANGELOG.md

@@ -1,3 +1,7 @@
+## Unreleased
+
+- feat(dm): add backward-compatible 2-byte TLV for Direct Messages with capability signaling to enable Cashu token DMs. Receive supports both 1B/2B; send uses 2B when peer advertises support. Enables integration with [bitpoints.me](https://github.com/bitpoints-cashu/bitpoints.me) for offline peer-to-peer Bitcoin payments.
+
 # Changelog
 
 All notable changes to this project will be documented in this file.

app/src/main/java/com/bitchat/android/mesh/BluetoothMeshService.kt

@@ -241,8 +241,8 @@ class BluetoothMeshService(private val context: Context) {
                 return peerManager.getPeerInfo(peerID)
             }
 
-            override fun updatePeerInfo(peerID: String, nickname: String, noisePublicKey: ByteArray, signingPublicKey: ByteArray, isVerified: Boolean): Boolean {
-                return peerManager.updatePeerInfo(peerID, nickname, noisePublicKey, signingPublicKey, isVerified)
+            override fun updatePeerInfo(peerID: String, nickname: String, noisePublicKey: ByteArray, signingPublicKey: ByteArray, isVerified: Boolean, features: Int): Boolean {
+                return peerManager.updatePeerInfo(peerID, nickname, noisePublicKey, signingPublicKey, isVerified, features)
             }
 
             // Packet operations
@@ -744,7 +744,8 @@ class BluetoothMeshService(private val context: Context) {
                         content = content
                     )
 
-                    val tlvData = privateMessage.encode()
+                    val use2Byte = peerManager.peerHasFeature(recipientPeerID, com.bitchat.android.protocol.ProtocolFeatures.DM_TLV_2BYTE)
+                    val tlvData = if (use2Byte) privateMessage.encode2B() else privateMessage.encode()
                     if (tlvData == null) {
                         Log.e(TAG, "Failed to encode private message with TLV")
                         return@launch
@@ -869,7 +870,7 @@ class BluetoothMeshService(private val context: Context) {
             }
 
             // Create iOS-compatible IdentityAnnouncement with TLV encoding
-            val announcement = IdentityAnnouncement(nickname, staticKey, signingKey)
+            val announcement = IdentityAnnouncement(nickname, staticKey, signingKey, com.bitchat.android.protocol.ProtocolFeatures.DM_TLV_2BYTE)
             val tlvPayload = announcement.encode()
             if (tlvPayload == null) {
                 Log.e(TAG, "Failed to encode announcement as TLV")
@@ -918,7 +919,7 @@ class BluetoothMeshService(private val context: Context) {
         }
 
         // Create iOS-compatible IdentityAnnouncement with TLV encoding
-        val announcement = IdentityAnnouncement(nickname, staticKey, signingKey)
+        val announcement = IdentityAnnouncement(nickname, staticKey, signingKey, com.bitchat.android.protocol.ProtocolFeatures.DM_TLV_2BYTE)
         val tlvPayload = announcement.encode()
         if (tlvPayload == null) {
             Log.e(TAG, "Failed to encode peer announcement as TLV")
@@ -1016,9 +1017,10 @@ class BluetoothMeshService(private val context: Context) {
         nickname: String,
         noisePublicKey: ByteArray,
         signingPublicKey: ByteArray,
-        isVerified: Boolean
+        isVerified: Boolean,
+        features: Int = 0
     ): Boolean {
-        return peerManager.updatePeerInfo(peerID, nickname, noisePublicKey, signingPublicKey, isVerified)
+        return peerManager.updatePeerInfo(peerID, nickname, noisePublicKey, signingPublicKey, isVerified, features)
     }
 
     /**

app/src/main/java/com/bitchat/android/mesh/MessageHandler.kt

@@ -267,7 +267,8 @@ class MessageHandler(private val myPeerID: String, private val appContext: andro
             nickname = nickname,
             noisePublicKey = noisePublicKey,
             signingPublicKey = signingPublicKey,
-            isVerified = true
+            isVerified = true,
+            features = announcement.features
         ) ?: false
 
         // Update peer ID binding with noise public key for identity management
@@ -583,7 +584,7 @@ interface MessageHandlerDelegate {
     fun getNetworkSize(): Int
     fun getMyNickname(): String?
     fun getPeerInfo(peerID: String): PeerInfo?
-    fun updatePeerInfo(peerID: String, nickname: String, noisePublicKey: ByteArray, signingPublicKey: ByteArray, isVerified: Boolean): Boolean
+    fun updatePeerInfo(peerID: String, nickname: String, noisePublicKey: ByteArray, signingPublicKey: ByteArray, isVerified: Boolean, features: Int = 0): Boolean
 
     // Packet operations
     fun sendPacket(packet: BitchatPacket)

app/src/main/java/com/bitchat/android/mesh/PeerManager.kt

@@ -17,7 +17,8 @@ data class PeerInfo(
     var noisePublicKey: ByteArray?,
     var signingPublicKey: ByteArray?,      // NEW: Ed25519 public key for verification
     var isVerifiedNickname: Boolean,       // NEW: Verification status flag
-    var lastSeen: Long  // Using Long instead of Date for simplicity
+    var lastSeen: Long,  // Using Long instead of Date for simplicity
+    var features: Int = 0                  // Feature bitmask from announcements
 ) {
     override fun equals(other: Any?): Boolean {
         if (this === other) return true
@@ -39,6 +40,7 @@ data class PeerInfo(
         } else if (other.signingPublicKey != null) return false
         if (isVerifiedNickname != other.isVerifiedNickname) return false
         if (lastSeen != other.lastSeen) return false
+        if (features != other.features) return false
 
         return true
     }
@@ -52,6 +54,7 @@ data class PeerInfo(
         result = 31 * result + (signingPublicKey?.contentHashCode() ?: 0)
         result = 31 * result + isVerifiedNickname.hashCode()
         result = 31 * result + lastSeen.hashCode()
+        result = 31 * result + features.hashCode()
         return result
     }
 }
@@ -104,7 +107,8 @@ class PeerManager {
         nickname: String,
         noisePublicKey: ByteArray,
         signingPublicKey: ByteArray,
-        isVerified: Boolean
+        isVerified: Boolean,
+        features: Int = 0
     ): Boolean {
         if (peerID == "unknown") return false
 
@@ -121,7 +125,8 @@ class PeerManager {
             noisePublicKey = noisePublicKey,
             signingPublicKey = signingPublicKey,
             isVerifiedNickname = isVerified,
-            lastSeen = now
+            lastSeen = now,
+            features = features
         )
 
         peers[peerID] = peerInfo
@@ -151,6 +156,14 @@ class PeerManager {
         return peers[peerID]
     }
 
+    /**
+     * Check if a peer advertises a feature bit.
+     */
+    fun peerHasFeature(peerID: String, featureBit: Int): Boolean {
+        val f = peers[peerID]?.features ?: 0
+        return (f and featureBit) != 0
+    }
+
     /**
      * Check if peer is verified
      */

app/src/main/java/com/bitchat/android/model/IdentityAnnouncement.kt

@@ -12,7 +12,8 @@ import com.bitchat.android.util.*
 data class IdentityAnnouncement(
     val nickname: String,
     val noisePublicKey: ByteArray,    // Noise static public key (Curve25519.KeyAgreement)
-    val signingPublicKey: ByteArray   // Ed25519 public key for signing
+    val signingPublicKey: ByteArray,  // Ed25519 public key for signing
+    val features: Int = 0             // Optional feature bitmask (unknown bits ignored by legacy)
 ) : Parcelable {
 
     /**
@@ -21,7 +22,8 @@ data class IdentityAnnouncement(
     private enum class TLVType(val value: UByte) {
         NICKNAME(0x01u),
         NOISE_PUBLIC_KEY(0x02u),
-        SIGNING_PUBLIC_KEY(0x03u);  // NEW: Ed25519 signing public key
+        SIGNING_PUBLIC_KEY(0x03u),  // NEW: Ed25519 signing public key
+        FEATURES(0x04u);            // Optional feature bitmask (u8 length, up to 4 bytes value)
 
         companion object {
             fun fromValue(value: UByte): TLVType? {
@@ -58,6 +60,21 @@ data class IdentityAnnouncement(
         result.add(signingPublicKey.size.toByte())
         result.addAll(signingPublicKey.toList())
 
+        // Optional: features bitmask (encode as minimal big-endian, up to 4 bytes)
+        if (features != 0) {
+            val featBytes = ByteArray(4)
+            featBytes[0] = ((features ushr 24) and 0xFF).toByte()
+            featBytes[1] = ((features ushr 16) and 0xFF).toByte()
+            featBytes[2] = ((features ushr 8) and 0xFF).toByte()
+            featBytes[3] = (features and 0xFF).toByte()
+            // Trim leading zeros to minimize length
+            val firstNonZero = featBytes.indexOfFirst { it.toInt() != 0 }
+            val valueBytes = if (firstNonZero == -1) byteArrayOf(0) else featBytes.copyOfRange(firstNonZero, 4)
+            result.add(TLVType.FEATURES.value.toByte())
+            result.add(valueBytes.size.toByte())
+            result.addAll(valueBytes.toList())
+        }
+
         return result.toByteArray()
     }
 
@@ -73,6 +90,7 @@ data class IdentityAnnouncement(
             var nickname: String? = null
             var noisePublicKey: ByteArray? = null
             var signingPublicKey: ByteArray? = null
+            var features: Int = 0
 
             while (offset + 2 <= dataCopy.size) {
                 // Read TLV type
@@ -102,6 +120,14 @@ data class IdentityAnnouncement(
                     TLVType.SIGNING_PUBLIC_KEY -> {
                         signingPublicKey = value
                     }
+                    TLVType.FEATURES -> {
+                        // Parse big-endian up to 4 bytes
+                        var f = 0
+                        value.forEach { b ->
+                            f = (f shl 8) or (b.toInt() and 0xFF)
+                        }
+                        features = f
+                    }
                     null -> {
                         // Unknown TLV; skip (tolerant decoder for forward compatibility)
                         continue
@@ -111,7 +137,7 @@ data class IdentityAnnouncement(
 
             // All three fields are required
             return if (nickname != null && noisePublicKey != null && signingPublicKey != null) {
-                IdentityAnnouncement(nickname, noisePublicKey, signingPublicKey)
+                IdentityAnnouncement(nickname, noisePublicKey, signingPublicKey, features)
             } else {
                 null
             }
@@ -128,6 +154,7 @@ data class IdentityAnnouncement(
         if (nickname != other.nickname) return false
         if (!noisePublicKey.contentEquals(other.noisePublicKey)) return false
         if (!signingPublicKey.contentEquals(other.signingPublicKey)) return false
+        if (features != other.features) return false
 
         return true
     }
@@ -136,10 +163,11 @@ data class IdentityAnnouncement(
         var result = nickname.hashCode()
         result = 31 * result + noisePublicKey.contentHashCode()
         result = 31 * result + signingPublicKey.contentHashCode()
+        result = 31 * result + features.hashCode()
         return result
     }
 
     override fun toString(): String {
-        return "IdentityAnnouncement(nickname='$nickname', noisePublicKey=${noisePublicKey.joinToString("") { "%02x".format(it) }.take(16)}..., signingPublicKey=${signingPublicKey.joinToString("") { "%02x".format(it) }.take(16)}...)"
+        return "IdentityAnnouncement(nickname='$nickname', noisePublicKey=${noisePublicKey.joinToString("") { "%02x".format(it) }.take(16)}..., signingPublicKey=${signingPublicKey.joinToString("") { "%02x".format(it) }.take(16)}..., features=$features)"
     }
 }

app/src/main/java/com/bitchat/android/model/NoiseEncrypted.kt

@@ -118,8 +118,8 @@ data class PrivateMessagePacket(
     }
 
     /**
-     * Encode to TLV binary data - exactly like iOS
-     * Format: [type][length][value] for each field
+     * Encode to TLV binary data (legacy 1-byte TLV)
+     * Format: [type:u8][length:u8][value] for each field
      */
     fun encode(): ByteArray? {
         val messageIDData = messageID.toByteArray(Charsets.UTF_8)
@@ -144,12 +144,47 @@ data class PrivateMessagePacket(
 
         return result.toByteArray()
     }
+
+    /**
+     * Encode to TLV binary data with 2-byte fields
+     * Format: [type:u16][length:u16][value]
+     */
+    fun encode2B(): ByteArray? {
+        val messageIDData = messageID.toByteArray(Charsets.UTF_8)
+        val contentData = content.toByteArray(Charsets.UTF_8)
+
+        // 2-byte length supports up to 65535
+        if (messageIDData.size > 0xFFFF || contentData.size > 0xFFFF) return null
+
+        val out = mutableListOf<Byte>()
+
+        fun put(type: UShort, value: ByteArray) {
+            // type u16
+            out.add(((type.toInt() ushr 8) and 0xFF).toByte())
+            out.add((type.toInt() and 0xFF).toByte())
+            // length u16
+            out.add(((value.size ushr 8) and 0xFF).toByte())
+            out.add((value.size and 0xFF).toByte())
+            out.addAll(value.toList())
+        }
+
+        put(0u, messageIDData)
+        put(1u, contentData)
+
+        return out.toByteArray()
+    }
 
     companion object {
         /**
          * Decode from TLV binary data - exactly like iOS
          */
         fun decode(data: ByteArray): PrivateMessagePacket? {
+            // Try 2-byte TLV first, then fallback to legacy 1-byte TLV
+            decode2B(data)?.let { return it }
+            return decode1B(data)
+        }
+
+        private fun decode1B(data: ByteArray): PrivateMessagePacket? {
             var offset = 0
             var messageID: String? = null
             var content: String? = null
@@ -187,6 +222,43 @@ data class PrivateMessagePacket(
                 null
             }
         }
+
+        private fun decode2B(data: ByteArray): PrivateMessagePacket? {
+            var offset = 0
+            var messageID: String? = null
+            var content: String? = null
+
+            while (offset + 4 <= data.size) {
+                // Read type u16
+                val tHigh = data[offset].toInt() and 0xFF
+                val tLow = data[offset + 1].toInt() and 0xFF
+                val type = (tHigh shl 8) or tLow
+                offset += 2
+
+                // Read length u16
+                if (offset + 2 > data.size) return null
+                val lHigh = data[offset].toInt() and 0xFF
+                val lLow = data[offset + 1].toInt() and 0xFF
+                val length = (lHigh shl 8) or lLow
+                offset += 2
+
+                if (length < 0 || offset + length > data.size) return null
+                val value = data.copyOfRange(offset, offset + length)
+                offset += length
+
+                when (type) {
+                    0 -> messageID = String(value, Charsets.UTF_8)
+                    1 -> content = String(value, Charsets.UTF_8)
+                    else -> {
+                        // Unknown type, ignore for forward compatibility
+                    }
+                }
+            }
+
+            return if (messageID != null && content != null) {
+                PrivateMessagePacket(messageID, content)
+            } else null
+        }
     }
 
     override fun toString(): String {

app/src/main/java/com/bitchat/android/protocol/ProtocolFeatures.kt

@@ -0,0 +1,6 @@
+package com.bitchat.android.protocol
+
+object ProtocolFeatures {
+    // Feature bits advertised in announcements (bitmask)
+    const val DM_TLV_2BYTE: Int = 1 shl 0
+}

app/src/test/java/com/bitchat/android/model/PrivateMessagePacketTest.kt

@@ -0,0 +1,31 @@
+package com.bitchat.android.model
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Test
+
+class PrivateMessagePacketTest {
+
+    @Test
+    fun encodeDecode1B_roundtrip() {
+        val pm = PrivateMessagePacket(messageID = "abc-123", content = "hello cashu")
+        val tlv = pm.encode()
+        assertNotNull(tlv)
+        val decoded = PrivateMessagePacket.decode(tlv!!)
+        assertNotNull(decoded)
+        assertEquals(pm.messageID, decoded!!.messageID)
+        assertEquals(pm.content, decoded.content)
+    }
+
+    @Test
+    fun encodeDecode2B_roundtrip() {
+        val longContent = "x".repeat(300)
+        val pm = PrivateMessagePacket(messageID = "id-300", content = longContent)
+        val tlv = pm.encode2B()
+        assertNotNull(tlv)
+        val decoded = PrivateMessagePacket.decode(tlv!!)
+        assertNotNull(decoded)
+        assertEquals(pm.messageID, decoded!!.messageID)
+        assertEquals(pm.content, decoded.content)
+    }
+}