Use decrypted proximity data if available

This change introduces the capability to decrypt the last 16 bytes of the proximity pairing message if an encryption key is available.

The decrypted payload provides more precise battery information (0-100% instead of 0-10%) and charging status for each pod and the case.

This information is now used by `DualApplePods` to enhance battery reporting accuracy.

The `RPAChecker` has also been updated with improved error logging.

app-common/src/main/java/eu/darken/capod/monitor/core/PodMonitor.kt

@@ -19,6 +19,7 @@ import eu.darken.capod.main.core.GeneralSettings
 import eu.darken.capod.main.core.PermissionTool
 import eu.darken.capod.pods.core.PodDevice
 import eu.darken.capod.pods.core.PodFactory
+import eu.darken.capod.monitor.core.RPAChecker
 import eu.darken.capod.pods.core.apple.protocol.ProximityPairing
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.delay

app-common/src/main/java/eu/darken/capod/monitor/core/RPAChecker.kt

@@ -1,7 +1,12 @@
 package eu.darken.capod.monitor.core
 
 import android.annotation.SuppressLint
+import eu.darken.capod.common.debug.logging.Logging.Priority.ERROR
+import eu.darken.capod.common.debug.logging.asLog
+import eu.darken.capod.common.debug.logging.log
+import eu.darken.capod.common.debug.logging.logTag
 import eu.darken.capod.pods.core.PodDevice
+import okio.ByteString.Companion.toByteString
 import javax.crypto.Cipher
 import javax.crypto.spec.SecretKeySpec
 import javax.inject.Inject
@@ -9,12 +14,15 @@ import javax.inject.Inject
 class RPAChecker @Inject constructor() {
 
     // Resolvable-Private-Address
-    fun verify(dev: PodDevice, irk: ByteArray): Boolean {
+    fun verify(dev: PodDevice, irk: ByteArray): Boolean = try {
         val rpa = dev.address.split(":").map { it.toInt(16).toByte() }.reversed().toByteArray()
         val prand = rpa.copyOfRange(3, 6)
         val hash = rpa.copyOfRange(0, 3)
         val computedHash = ah(irk, prand)
-        return hash.contentEquals(computedHash)
+        hash.contentEquals(computedHash)
+    } catch (e: Exception) {
+        log(TAG, ERROR) { "Failed to verify RPA\nPod=${dev}\nIRK=${irk.toByteString()}\n${e.asLog()}" }
+        false
     }
 
     // E function (Encryption function):
@@ -34,4 +42,8 @@ class RPAChecker @Inject constructor() {
         }
         return e(k, rPadded).copyOfRange(0, 3)
     }
+
+    companion object {
+        private val TAG = logTag("Monitor", "PodMonitor", "RPAChecker")
+    }
 }

app-common/src/main/java/eu/darken/capod/pods/core/apple/AppleFactory.kt

@@ -5,9 +5,11 @@ import eu.darken.capod.common.debug.logging.Logging.Priority.WARN
 import eu.darken.capod.common.debug.logging.asLog
 import eu.darken.capod.common.debug.logging.log
 import eu.darken.capod.common.debug.logging.logTag
+import eu.darken.capod.main.core.GeneralSettings
 import eu.darken.capod.pods.core.PodDevice
 import eu.darken.capod.pods.core.apple.misc.UnknownAppleDevice
 import eu.darken.capod.pods.core.apple.protocol.ContinuityProtocol
+import eu.darken.capod.pods.core.apple.protocol.MessageDecrypter
 import eu.darken.capod.pods.core.apple.protocol.ProximityPairing
 import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
@@ -20,6 +22,8 @@ class AppleFactory @Inject constructor(
     private val proximityPairingDecoder: ProximityPairing.Decoder,
     private val podFactories: @JvmSuppressWildcards Set<ApplePodsFactory<out ApplePods>>,
     private val unknownAppleFactory: UnknownAppleDevice.Factory,
+    private val generalSettings: GeneralSettings,
+    private val messageDecrypter: MessageDecrypter,
 ) {
 
     private val lock = Mutex()
@@ -54,9 +58,13 @@ class AppleFactory @Inject constructor(
 
         val factory = podFactories.firstOrNull { it.isResponsible(pm) }
 
+        val decryptedData = generalSettings.mainDeviceEncryptionKey.value
+            ?.let { messageDecrypter.decrypt(pm, it) }
+
         return@withLock (factory ?: unknownAppleFactory).create(
             scanResult = scanResult,
             message = pm,
+            decrypted = decryptedData,
         )
     }
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/ApplePods.kt

@@ -10,6 +10,9 @@ interface ApplePods : PodDevice {
 
     val proximityMessage: ProximityPairing.Message
 
+    val decryptedPayload: UByteArray?
+        get() = null
+
     // We start counting at the airpods prefix byte
     val rawPrefix: UByte
         get() = proximityMessage.data[0]

app-common/src/main/java/eu/darken/capod/pods/core/apple/ApplePodsFactory.kt

@@ -202,5 +202,6 @@ abstract class ApplePodsFactory<PodType : ApplePods>(private val tag: String) {
     abstract fun create(
         scanResult: BleScanResult,
         message: ProximityPairing.Message,
+        decrypted: UByteArray?,
     ): ApplePods
 }

app-common/src/main/java/eu/darken/capod/pods/core/apple/DualApplePods.kt

@@ -4,8 +4,12 @@ import eu.darken.capod.common.debug.logging.log
 import eu.darken.capod.common.isBitSet
 import eu.darken.capod.common.lowerNibble
 import eu.darken.capod.common.upperNibble
-import eu.darken.capod.pods.core.*
+import eu.darken.capod.pods.core.DualPodDevice
 import eu.darken.capod.pods.core.DualPodDevice.Pod
+import eu.darken.capod.pods.core.HasCase
+import eu.darken.capod.pods.core.HasChargeDetectionDual
+import eu.darken.capod.pods.core.HasDualMicrophone
+import eu.darken.capod.pods.core.HasEarDetectionDual
 
 interface DualApplePods : ApplePods, HasChargeDetectionDual, DualPodDevice, HasEarDetectionDual, HasCase,
     HasDualMicrophone, HasAppleColor {
@@ -25,6 +29,10 @@ interface DualApplePods : ApplePods, HasChargeDetectionDual, DualPodDevice, HasE
 
     override val batteryLeftPodPercent: Float?
         get() {
+            decryptedPayload?.get(if (areValuesFlipped) 2 else 1)?.let { raw ->
+                val level = (raw and 0x7Fu).toInt() / 100f
+                if (level <= 1.0f) return level
+            }
             val value = when (areValuesFlipped) {
                 true -> rawPodsBattery.upperNibble.toInt()
                 false -> rawPodsBattery.lowerNibble.toInt()
@@ -42,6 +50,10 @@ interface DualApplePods : ApplePods, HasChargeDetectionDual, DualPodDevice, HasE
 
     override val batteryRightPodPercent: Float?
         get() {
+            decryptedPayload?.get(if (areValuesFlipped) 1 else 2)?.let { raw ->
+                val level = (raw and 0x7Fu).toInt() / 100f
+                if (level <= 1.0f) return level
+            }
             val value = when (areValuesFlipped) {
                 true -> rawPodsBattery.lowerNibble.toInt()
                 false -> rawPodsBattery.upperNibble.toInt()
@@ -93,30 +105,55 @@ interface DualApplePods : ApplePods, HasChargeDetectionDual, DualPodDevice, HasE
         get() = !rawStatus.isBitSet(5) xor isThisPodInThecase
 
     override val isLeftPodCharging: Boolean
-        get() = when (areValuesFlipped) {
-            false -> rawFlags.isBitSet(0)
-            true -> rawFlags.isBitSet(1)
+        get() {
+            decryptedPayload?.get(if (areValuesFlipped) 2 else 1)?.let { raw ->
+                val isCharging = (raw and 0x80u).toInt() != 0
+                return isCharging
+            }
+            return when (areValuesFlipped) {
+                false -> rawFlags.isBitSet(0)
+                true -> rawFlags.isBitSet(1)
+            }
         }
 
     override val isRightPodCharging: Boolean
-        get() = when (areValuesFlipped) {
-            false -> rawFlags.isBitSet(1)
-            true -> rawFlags.isBitSet(0)
+        get() {
+            decryptedPayload?.get(if (areValuesFlipped) 1 else 2)?.let { raw ->
+                val isCharging = (raw and 0x80u).toInt() != 0
+                return isCharging
+            }
+            return when (areValuesFlipped) {
+                false -> rawFlags.isBitSet(1)
+                true -> rawFlags.isBitSet(0)
+            }
         }
 
     override val batteryCasePercent: Float?
-        get() = when (val value = rawCaseBattery.toInt()) {
-            15 -> null
-            else -> if (value > 10) {
-                log { "Case: Above 100% battery: $value" }
-                1.0f
-            } else {
-                value / 10f
+        get() {
+            decryptedPayload?.get(3)?.let { raw ->
+                val level = (raw and 0x7Fu).toInt() / 100f
+                if (level <= 1.0f) return level
+            }
+            return when (val value = rawCaseBattery.toInt()) {
+                15 -> null
+                else -> if (value > 10) {
+                    log { "Case: Above 100% battery: $value" }
+                    1.0f
+                } else {
+                    value / 10f
+                }
             }
         }
 
     override val isCaseCharging: Boolean
-        get() = rawFlags.isBitSet(2)
+        get() {
+            decryptedPayload?.get(3)?.let { raw ->
+                val isCharging = (raw and 0x80u).toInt() != 0
+                if (batteryCasePercent != null) return isCharging
+            }
+
+            return rawFlags.isBitSet(2)
+        }
 
     val caseLidState: LidState
         get() {

app-common/src/main/java/eu/darken/capod/pods/core/apple/airpods/AirPodsGen1.kt

@@ -41,7 +41,11 @@ data class AirPodsGen1 constructor(
         }
 
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = AirPodsGen1(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/airpods/AirPodsGen2.kt

@@ -40,7 +40,11 @@ data class AirPodsGen2 constructor(
             getModelInfo().full == DEVICE_CODE && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = AirPodsGen2(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/airpods/AirPodsGen3.kt

@@ -40,7 +40,11 @@ data class AirPodsGen3 constructor(
             getModelInfo().full == DEVICE_CODE && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = AirPodsGen3(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/airpods/AirPodsGen4.kt

@@ -40,7 +40,11 @@ data class AirPodsGen4(
             getModelInfo().full == DEVICE_CODE && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = AirPodsGen4(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/airpods/AirPodsGen4Anc.kt

@@ -40,7 +40,11 @@ data class AirPodsGen4Anc(
             getModelInfo().full == DEVICE_CODE && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = AirPodsGen4Anc(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/airpods/AirPodsMax.kt

@@ -42,7 +42,11 @@ data class AirPodsMax(
             getModelInfo().full == DEVICE_CODE && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = AirPodsMax(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/airpods/AirPodsMaxUsbc.kt

@@ -42,7 +42,11 @@ data class AirPodsMaxUsbc(
             getModelInfo().full == DEVICE_CODE && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = AirPodsMaxUsbc(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/airpods/AirPodsPro.kt

@@ -20,6 +20,7 @@ data class AirPodsPro(
     override val seenCounter: Int = 1,
     override val scanResult: BleScanResult,
     override val proximityMessage: ProximityPairing.Message,
+    override val decryptedPayload: UByteArray?,
     override val reliability: Float = PodDevice.BASE_CONFIDENCE,
     private val rssiAverage: Int? = null,
     private val cachedBatteryPercentage: Float? = null,
@@ -59,8 +60,16 @@ data class AirPodsPro(
             getModelInfo().full == DEVICE_CODE && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
-            var basic = AirPodsPro(scanResult = scanResult, proximityMessage = message)
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
+            var basic = AirPodsPro(
+                scanResult = scanResult,
+                proximityMessage = message,
+                decryptedPayload = decrypted
+            )
             val result = searchHistory(basic)
 
             if (result != null) basic = basic.copy(identifier = result.id)
@@ -79,7 +88,6 @@ data class AirPodsPro(
                 cachedCaseState = result.getLatestCaseLidState(basic)
             )
         }
-
     }
 
     companion object {

app-common/src/main/java/eu/darken/capod/pods/core/apple/airpods/AirPodsPro2.kt

@@ -59,7 +59,11 @@ data class AirPodsPro2(
             getModelInfo().full == DEVICE_CODE && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = AirPodsPro2(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/airpods/AirPodsPro2Usbc.kt

@@ -59,7 +59,11 @@ data class AirPodsPro2Usbc(
             getModelInfo().full == DEVICE_CODE && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = AirPodsPro2Usbc(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/beats/BeatsFitPro.kt

@@ -40,7 +40,11 @@ data class BeatsFitPro(
             getModelInfo().full == DEVICE_CODE && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = BeatsFitPro(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/beats/BeatsFlex.kt

@@ -32,7 +32,11 @@ data class BeatsFlex(
             getModelInfo().full == DEVICE_CODE && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = BeatsFlex(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/beats/BeatsSolo3.kt

@@ -31,7 +31,11 @@ data class BeatsSolo3(
             getModelInfo().full == DEVICE_CODE && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = BeatsSolo3(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/beats/BeatsStudio3.kt

@@ -29,7 +29,11 @@ data class BeatsStudio3(
             getModelInfo().dirty == DEVICE_CODE_DIRTY && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = BeatsStudio3(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/beats/BeatsX.kt

@@ -32,7 +32,11 @@ data class BeatsX(
             getModelInfo().full == DEVICE_CODE && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = BeatsX(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/beats/PowerBeats3.kt

@@ -32,7 +32,11 @@ data class PowerBeats3(
             getModelInfo().full == DEVICE_CODE && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = PowerBeats3(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/beats/PowerBeats4.kt

@@ -33,7 +33,11 @@ data class PowerBeats4(
             getModelInfo().full == DEVICE_CODE && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = PowerBeats4(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/beats/PowerBeatsPro.kt

@@ -40,7 +40,11 @@ data class PowerBeatsPro(
             getModelInfo().dirty == DEVICE_CODE_DIRTY && length == ProximityPairing.PAIRING_MESSAGE_LENGTH
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = PowerBeatsPro(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/misc/FakeAirPodsGen1.kt

@@ -124,7 +124,11 @@ data class FakeAirPodsGen1 constructor(
             getModelInfo().full == DEVICE_CODE && length == 19
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = FakeAirPodsGen1(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/misc/FakeAirPodsGen2.kt

@@ -122,7 +122,11 @@ data class FakeAirPodsGen2 constructor(
             getModelInfo().full == DEVICE_CODE && length == 19
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = FakeAirPodsGen2(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/misc/FakeAirPodsGen3.kt

@@ -124,7 +124,11 @@ data class FakeAirPodsGen3 constructor(
             getModelInfo().full == DEVICE_CODE && length == 19
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = FakeAirPodsGen3(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/misc/FakeAirPodsPro.kt

@@ -142,7 +142,11 @@ data class FakeAirPodsPro constructor(
             getModelInfo().full == DEVICE_CODE && length == 19
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = FakeAirPodsPro(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/misc/FakeAirPodsPro2.kt

@@ -139,7 +139,11 @@ data class FakeAirPodsPro2 constructor(
             getModelInfo().full == DEVICE_CODE && length == 19
         }
 
-        override fun create(scanResult: BleScanResult, message: ProximityPairing.Message): ApplePods {
+        override fun create(
+            scanResult: BleScanResult,
+            message: ProximityPairing.Message,
+            decrypted: UByteArray?
+        ): ApplePods {
             var basic = FakeAirPodsPro2(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)
 

app-common/src/main/java/eu/darken/capod/pods/core/apple/misc/UnknownAppleDevice.kt

@@ -35,6 +35,7 @@ data class UnknownAppleDevice(
         override fun create(
             scanResult: BleScanResult,
             message: ProximityPairing.Message,
+            decrypted: UByteArray?,
         ): ApplePods {
             var basic = UnknownAppleDevice(scanResult = scanResult, proximityMessage = message)
             val result = searchHistory(basic)

app-common/src/main/java/eu/darken/capod/pods/core/apple/protocol/MessageDecrypter.kt

@@ -0,0 +1,44 @@
+package eu.darken.capod.pods.core.apple.protocol
+
+import android.annotation.SuppressLint
+import eu.darken.capod.common.debug.logging.Logging
+import eu.darken.capod.common.debug.logging.asLog
+import eu.darken.capod.common.debug.logging.log
+import eu.darken.capod.common.debug.logging.logTag
+import okio.ByteString.Companion.toByteString
+import javax.crypto.Cipher
+import javax.crypto.spec.SecretKeySpec
+import javax.inject.Inject
+
+class MessageDecrypter @Inject constructor() {
+
+    @SuppressLint("GetInstance")
+    fun decrypt(message: ProximityPairing.Message, key: ByteArray): UByteArray? {
+        val data = message.data.toByteArray()
+        if (data.size < 16) return null
+
+        val decryptedData = try {
+            val cipher = Cipher.getInstance("AES/ECB/NoPadding").apply {
+                val secretKey = SecretKeySpec(key, "AES")
+                init(Cipher.DECRYPT_MODE, secretKey)
+            }
+            cipher.doFinal(data.copyOfRange(data.size - 16, data.size))
+        } catch (e: Exception) {
+            log(TAG, Logging.Priority.ERROR) { "Failed to decrypt $message with ${key.toByteString()}\n${e.asLog()}" }
+            null
+        }
+
+        log(
+            TAG,
+            Logging.Priority.VERBOSE
+        ) { "Decrypted $message with ${key.toByteString()} to ${decryptedData?.toByteString()}" }
+
+        if (decryptedData == null || decryptedData.size != 16) return null
+
+        return decryptedData.toUByteArray()
+    }
+
+    companion object {
+        private val TAG = logTag("Pod", "Factory", "Decrypter")
+    }
+}