diff --git a/app/src/test/kotlin/com/bitchat/android/protocol/BinaryProtocolTest.kt b/app/src/test/kotlin/com/bitchat/android/protocol/BinaryProtocolTest.kt
new file mode 100644
index 00000000..03f41b6d
--- /dev/null
+++ b/app/src/test/kotlin/com/bitchat/android/protocol/BinaryProtocolTest.kt
@@ -0,0 +1,154 @@
+package com.bitchat.android.protocol
+
+import org.junit.Assert.*
+import org.junit.Test
+
+class BinaryProtocolTest {
+
+    private val senderID = hexStringToPeerBytes("1111111111111111")
+    private val recipientID = hexStringToPeerBytes("2222222222222222")
+    private val hop1 = hexStringToPeerBytes("aaaaaaaaaaaaaaaa")
+    private val hop2 = hexStringToPeerBytes("bbbbbbbbbbbbbbbb")
+
+    @Test
+    fun `v1 packet ignores route field during encoding`() {
+        val packet = BitchatPacket(
+            version = 1u,
+            type = MessageType.MESSAGE.value,
+            senderID = senderID,
+            recipientID = recipientID,
+            timestamp = 1234567890UL,
+            payload = "hello".toByteArray(),
+            ttl = 5u,
+            route = listOf(hop1, hop2)
+        )
+
+        val encoded = BinaryProtocol.encode(packet)
+        assertNotNull(encoded)
+
+        val decoded = BinaryProtocol.decode(encoded!!)
+        assertNotNull(decoded)
+
+        // V1 should NOT have route even though we provided one
+        assertEquals(1u.toUByte(), decoded!!.version)
+        assertNull("V1 packet should not contain route", decoded.route)
+    }
+
+    @Test
+    fun `v2 packet encodes and decodes route field`() {
+        val packet = BitchatPacket(
+            version = 2u,
+            type = MessageType.MESSAGE.value,
+            senderID = senderID,
+            recipientID = recipientID,
+            timestamp = 1234567890UL,
+            payload = "hello".toByteArray(),
+            ttl = 5u,
+            route = listOf(hop1, hop2)
+        )
+
+        val encoded = BinaryProtocol.encode(packet)
+        assertNotNull(encoded)
+
+        val decoded = BinaryProtocol.decode(encoded!!)
+        assertNotNull(decoded)
+
+        // V2 should have the route
+        assertEquals(2u.toUByte(), decoded!!.version)
+        assertNotNull("V2 packet should contain route", decoded.route)
+        assertEquals(2, decoded.route!!.size)
+        assertArrayEquals(hop1, decoded.route!![0])
+        assertArrayEquals(hop2, decoded.route!![1])
+    }
+
+    @Test
+    fun `v2 packet without route encodes and decodes correctly`() {
+        val packet = BitchatPacket(
+            version = 2u,
+            type = MessageType.MESSAGE.value,
+            senderID = senderID,
+            recipientID = recipientID,
+            timestamp = 1234567890UL,
+            payload = "hello".toByteArray(),
+            ttl = 5u,
+            route = null
+        )
+
+        val encoded = BinaryProtocol.encode(packet)
+        assertNotNull(encoded)
+
+        val decoded = BinaryProtocol.decode(encoded!!)
+        assertNotNull(decoded)
+
+        assertEquals(2u.toUByte(), decoded!!.version)
+        assertNull("V2 packet with no route should decode with null route", decoded.route)
+    }
+
+    @Test
+    fun `v1 packet round-trips correctly without route`() {
+        val packet = BitchatPacket(
+            version = 1u,
+            type = MessageType.MESSAGE.value,
+            senderID = senderID,
+            recipientID = recipientID,
+            timestamp = 1234567890UL,
+            payload = "test payload".toByteArray(),
+            ttl = 3u,
+            route = null
+        )
+
+        val encoded = BinaryProtocol.encode(packet)
+        assertNotNull(encoded)
+
+        val decoded = BinaryProtocol.decode(encoded!!)
+        assertNotNull(decoded)
+
+        assertEquals(1u.toUByte(), decoded!!.version)
+        assertEquals(MessageType.MESSAGE.value, decoded.type)
+        assertArrayEquals(senderID, decoded.senderID)
+        assertArrayEquals(recipientID, decoded.recipientID)
+        assertEquals(1234567890UL, decoded.timestamp)
+        assertArrayEquals("test payload".toByteArray(), decoded.payload)
+        assertNull(decoded.route)
+    }
+
+    @Test
+    fun `v2 packet decoding logic correctly identifies route count`() {
+        // Construct a packet where the first byte of senderID is a high value (e.g. 0x87 = 135)
+        // If the decoder peeks at the wrong offset (the senderID), it will think route count is 135
+        // and expect a huge packet size, causing decode to return null.
+        val trickySenderID = hexStringToPeerBytes("872b3ccb2c3eb8c7") 
+        val packet = BitchatPacket(
+            version = 2u,
+            type = MessageType.MESSAGE.value,
+            senderID = trickySenderID,
+            recipientID = recipientID,
+            timestamp = 1234567890UL,
+            payload = "bugcheck".toByteArray(),
+            ttl = 5u,
+            route = listOf(hop1) // Actual route count is 1
+        )
+
+        val encoded = BinaryProtocol.encode(packet)
+        assertNotNull(encoded)
+
+        val decoded = BinaryProtocol.decode(encoded!!)
+        assertNotNull("Decoding failed - likely due to incorrect route count peek", decoded)
+        
+        assertEquals(2u.toUByte(), decoded!!.version)
+        assertEquals(1, decoded.route!!.size)
+        assertArrayEquals(trickySenderID, decoded.senderID)
+    }
+
+    private fun hexStringToPeerBytes(hex: String): ByteArray {
+        val result = ByteArray(8)
+        var idx = 0
+        var out = 0
+        while (idx + 1 < hex.length && out < 8) {
+            val b = hex.substring(idx, idx + 2).toIntOrNull(16)?.toByte() ?: 0
+            result[out++] = b
+            idx += 2
+        }
+        return result
+    }
+}