Reduce complexity of function

changelog.d/8212.feature

@@ -0,0 +1 @@
+Updates to protocol used for Sign in with QR code

matrix-sdk-android/src/androidTest/java/org/matrix/android/sdk/api/rendezvous/RendezvousTest.kt

@@ -25,27 +25,53 @@ import org.junit.Test
 import org.matrix.android.sdk.InstrumentedTest
 import org.matrix.android.sdk.api.rendezvous.channels.ECDHRendezvousChannel
 import org.matrix.android.sdk.api.rendezvous.model.RendezvousError
+import org.matrix.android.sdk.api.rendezvous.model.RendezvousFlow
 import org.matrix.android.sdk.common.CommonTestHelper
 
 class RendezvousTest : InstrumentedTest {
 
     @Test
-    fun shouldSuccessfullyBuildChannels() = CommonTestHelper.runCryptoTest(context()) { _, _ ->
+    fun shouldSuccessfullyBuildMSC3906V1Channels() = CommonTestHelper.runCryptoTest(context()) { _, _ ->
         val cases = listOf(
-            // v1:
+            // MSC3903 v1 + MSC3906 v1:
             "{\"rendezvous\":{\"algorithm\":\"org.matrix.msc3903.rendezvous.v1.curve25519-aes-sha256\"," +
             "\"key\":\"aeSGwYTV1IUhikUyCapzC6p2xG5NpJ4Lwj2UgUMlcTk\",\"transport\":" +
             "{\"type\":\"org.matrix.msc3886.http.v1\",\"uri\":\"https://rendezvous.lab.element.dev/bcab62cd-3e34-48b4-bc39-90895da8f6fe\"}}," +
             "\"intent\":\"login.reciprocate\"}",
-            // v2:
+            // MSC3903 v2 + MSC3906 v1:
             "{\"rendezvous\":{\"algorithm\":\"org.matrix.msc3903.rendezvous.v2.curve25519-aes-sha256\"," +
             "\"key\":\"aeSGwYTV1IUhikUyCapzC6p2xG5NpJ4Lwj2UgUMlcTk\",\"transport\":" +
             "{\"type\":\"org.matrix.msc3886.http.v1\",\"uri\":\"https://rendezvous.lab.element.dev/bcab62cd-3e34-48b4-bc39-90895da8f6fe\"}}," +
-            "\"intent\":\"login.reciprocate\"}",
+            "\"intent\":\"login.reciprocate\"}"
         )
 
         cases.forEach { input ->
-            Rendezvous.buildChannelFromCode(input).channel shouldBeInstanceOf ECDHRendezvousChannel::class
+            val rz = Rendezvous.buildChannelFromCode(input)
+            rz.channel shouldBeInstanceOf ECDHRendezvousChannel::class
+            rz.flow shouldBeEqualTo RendezvousFlow.SETUP_ADDITIONAL_DEVICE_V1
+        }
+    }
+
+    fun shouldSuccessfullyBuildMSC3906V2Channels() = CommonTestHelper.runCryptoTest(context()) { _, _ ->
+        val cases = listOf(
+                // MSC3903 v1:
+                "{\"rendezvous\":{\"algorithm\":\"org.matrix.msc3903.rendezvous.v1.curve25519-aes-sha256\"," +
+                        "\"key\":\"aeSGwYTV1IUhikUyCapzC6p2xG5NpJ4Lwj2UgUMlcTk\",\"transport\":" +
+                        "{\"type\":\"org.matrix.msc3886.http.v1\",\"uri\":\"https://rendezvous.lab.element.dev/bcab62cd-3e34-48b4-bc39-90895da8f6fe\"}}," +
+                        "\"flow\":\"org.matrix.msc3906.setup.additional_device.v2\"," +
+                        "\"intent\":\"login.reciprocate\"}",
+                // MSC3903 v2:
+                "{\"rendezvous\":{\"algorithm\":\"org.matrix.msc3903.rendezvous.v2.curve25519-aes-sha256\"," +
+                        "\"key\":\"aeSGwYTV1IUhikUyCapzC6p2xG5NpJ4Lwj2UgUMlcTk\",\"transport\":" +
+                        "{\"type\":\"org.matrix.msc3886.http.v1\",\"uri\":\"https://rendezvous.lab.element.dev/bcab62cd-3e34-48b4-bc39-90895da8f6fe\"}}," +
+                        "\"flow\":\"org.matrix.msc3906.setup.additional_device.v2\"," +
+                        "\"intent\":\"login.reciprocate\"}"
+        )
+
+        cases.forEach { input ->
+            val rz = Rendezvous.buildChannelFromCode(input)
+            rz.channel shouldBeInstanceOf ECDHRendezvousChannel::class
+            rz.flow shouldBeEqualTo RendezvousFlow.SETUP_ADDITIONAL_DEVICE_V2
         }
     }
 
@@ -56,6 +82,7 @@ class RendezvousTest : InstrumentedTest {
                 "{\"rendezvous\":{\"algorithm\":\"bad algo\"," +
                 "\"key\":\"aeSGwYTV1IUhikUyCapzC6p2xG5NpJ4Lwj2UgUMlcTk\",\"transport\":" +
                 "{\"type\":\"org.matrix.msc3886.http.v1\",\"uri\":\"https://rendezvous.lab.element.dev/bcab62cd-3e34-48b4-bc39-90895da8f6fe\"}}," +
+                "\"flow\":\"org.matrix.msc3906.setup.additional_device.v2\"," +
                 "\"intent\":\"login.reciprocate\"}"
             )
         } shouldThrow RendezvousError::class with {
@@ -70,6 +97,7 @@ class RendezvousTest : InstrumentedTest {
                     "{\"rendezvous\":{\"algorithm\":\"org.matrix.msc3903.rendezvous.v1.curve25519-aes-sha256\"," +
                             "\"key\":\"aeSGwYTV1IUhikUyCapzC6p2xG5NpJ4Lwj2UgUMlcTk\",\"transport\":" +
                             "{\"type\":\"bad transport\",\"uri\":\"https://rendezvous.lab.element.dev/bcab62cd-3e34-48b4-bc39-90895da8f6fe\"}}," +
+                            "\"flow\":\"org.matrix.msc3906.setup.additional_device.v2\"," +
                             "\"intent\":\"login.reciprocate\"}"
             )
         } shouldThrow RendezvousError::class with {
@@ -84,6 +112,7 @@ class RendezvousTest : InstrumentedTest {
                     "{\"rendezvous\":{\"algorithm\":\"org.matrix.msc3903.rendezvous.v1.curve25519-aes-sha256\"," +
                             "\"key\":\"aeSGwYTV1IUhikUyCapzC6p2xG5NpJ4Lwj2UgUMlcTk\",\"transport\":" +
                             "{\"type\":\"org.matrix.msc3886.http.v1\",\"uri\":\"https://rendezvous.lab.element.dev/bcab62cd-3e34-48b4-bc39-90895da8f6fe\"}}," +
+                            "\"flow\":\"org.matrix.msc3906.setup.additional_device.v2\"," +
                             "\"intent\":\"foo\"}"
             )
         } shouldThrow RendezvousError::class with {

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/rendezvous/Rendezvous.kt

@@ -22,12 +22,14 @@ import org.matrix.android.sdk.api.auth.data.HomeServerConnectionConfig
 import org.matrix.android.sdk.api.logger.LoggerTag
 import org.matrix.android.sdk.api.rendezvous.channels.ECDHRendezvousChannel
 import org.matrix.android.sdk.api.rendezvous.model.ECDHRendezvousCode
+import org.matrix.android.sdk.api.rendezvous.model.FailureReason
 import org.matrix.android.sdk.api.rendezvous.model.Outcome
 import org.matrix.android.sdk.api.rendezvous.model.Payload
 import org.matrix.android.sdk.api.rendezvous.model.PayloadType
 import org.matrix.android.sdk.api.rendezvous.model.Protocol
 import org.matrix.android.sdk.api.rendezvous.model.RendezvousCode
 import org.matrix.android.sdk.api.rendezvous.model.RendezvousError
+import org.matrix.android.sdk.api.rendezvous.model.RendezvousFlow
 import org.matrix.android.sdk.api.rendezvous.model.RendezvousIntent
 import org.matrix.android.sdk.api.rendezvous.model.RendezvousTransportType
 import org.matrix.android.sdk.api.rendezvous.model.SecureRendezvousChannelAlgorithm
@@ -42,11 +44,14 @@ import org.matrix.android.sdk.api.util.MatrixJsonParser
 import timber.log.Timber
 
 /**
- * Implementation of MSC3906 to sign in + E2EE set up using a QR code.
+ * Implementation of MSC3906 to sign in + E2EE set up using a QR code: https://github.com/matrix-org/matrix-spec-proposals/pull/3906
+ *
+ * @alpha This is an experimental API, and is subject to change until MSC3906 is stabilised and accepted.
  */
 class Rendezvous(
         val channel: RendezvousChannel,
         val theirIntent: RendezvousIntent,
+        val flow: RendezvousFlow,
 ) {
     companion object {
         private val TAG = LoggerTag(Rendezvous::class.java.simpleName, LoggerTag.RENDEZVOUS).value
@@ -61,6 +66,11 @@ class Rendezvous(
                 throw RendezvousError("Malformed code", RendezvousFailureReason.InvalidCode)
             } ?: throw RendezvousError("Code is null", RendezvousFailureReason.InvalidCode)
 
+            // then we check that flow is supported
+            if (genericParsed.flow != null && !RendezvousFlow.values().map { it.value }.contains(genericParsed.flow)) {
+                throw RendezvousError("Unsupported flow", RendezvousFailureReason.UnsupportedAlgorithm)
+            }
+
             // then we check that algorithm is supported
             if (!SecureRendezvousChannelAlgorithm.values().map { it.value }.contains(genericParsed.rendezvous.algorithm)) {
                 throw RendezvousError("Unsupported algorithm", RendezvousFailureReason.UnsupportedAlgorithm)
@@ -83,25 +93,33 @@ class Rendezvous(
 
             return Rendezvous(
                     ECDHRendezvousChannel(transport, supportedParsed.rendezvous.algorithm, supportedParsed.rendezvous.key),
-                    supportedParsed.intent
+                    supportedParsed.intent,
+                    // default to v1 if not specified:
+                    supportedParsed.flow ?: RendezvousFlow.SETUP_ADDITIONAL_DEVICE_V1
             )
         }
     }
 
     private val adapter = MatrixJsonParser.getMoshi().adapter(Payload::class.java)
 
-    // not yet implemented: RendezvousIntent.RECIPROCATE_LOGIN_ON_EXISTING_DEVICE
-    val ourIntent: RendezvousIntent = RendezvousIntent.LOGIN_ON_NEW_DEVICE
+    fun isUsingV1(): Boolean = flow == RendezvousFlow.SETUP_ADDITIONAL_DEVICE_V1
 
     @Throws(RendezvousError::class)
     private suspend fun checkCompatibility() {
+        // not yet implemented: RendezvousIntent.RECIPROCATE_LOGIN_ON_EXISTING_DEVICE
+        val ourIntent: RendezvousIntent = RendezvousIntent.LOGIN_ON_NEW_DEVICE
+
         val incompatible = theirIntent == ourIntent
 
-        Timber.tag(TAG).d("ourIntent: $ourIntent, theirIntent: $theirIntent, incompatible: $incompatible")
+        Timber.tag(TAG).d("ourIntent: $ourIntent, theirIntent: $theirIntent, incompatible: $incompatible, flow: $flow")
 
         if (incompatible) {
             // inform the other side
-            send(Payload(PayloadType.FINISH, intent = ourIntent))
+            if (isUsingV1()) {
+                send(Payload(PayloadType.FINISH, intent = ourIntent))
+            } else {
+                send(Payload(PayloadType.FAILURE, intent = ourIntent))
+            }
             if (ourIntent == RendezvousIntent.LOGIN_ON_NEW_DEVICE) {
                 throw RendezvousError("The other device isn't signed in", RendezvousFailureReason.OtherDeviceNotSignedIn)
             } else {
@@ -123,11 +141,19 @@ class Rendezvous(
         val protocolsResponse = receive()
 
         if (protocolsResponse?.protocols == null || !protocolsResponse.protocols.contains(Protocol.LOGIN_TOKEN)) {
-            send(Payload(PayloadType.FINISH, outcome = Outcome.UNSUPPORTED))
+            if (isUsingV1()) {
+                send(Payload(PayloadType.FINISH, outcome = Outcome.UNSUPPORTED))
+            } else {
+                send(Payload(PayloadType.FAILURE, reason = FailureReason.UNSUPPORTED))
+            }
             throw RendezvousError("Unsupported protocols", RendezvousFailureReason.UnsupportedHomeserver)
         }
 
-        send(Payload(PayloadType.PROGRESS, protocol = Protocol.LOGIN_TOKEN))
+        if (isUsingV1()) {
+            send(Payload(PayloadType.PROGRESS, protocol = Protocol.LOGIN_TOKEN))
+        } else {
+            send(Payload(PayloadType.PROTOCOL, protocol = Protocol.LOGIN_TOKEN))
+        }
 
         return checksum
     }
@@ -138,6 +164,7 @@ class Rendezvous(
 
         val loginToken = receive()
 
+        // v1:
         if (loginToken?.type == PayloadType.FINISH) {
             when (loginToken.outcome) {
                 Outcome.DECLINED -> {
@@ -152,6 +179,28 @@ class Rendezvous(
             }
         }
 
+        // v2:
+        if (loginToken?.type == PayloadType.DECLINED) {
+            throw RendezvousError("Login declined by other device", RendezvousFailureReason.UserDeclined)
+        }
+        if (loginToken?.type == PayloadType.FAILURE) {
+            when (loginToken.reason) {
+                FailureReason.UNSUPPORTED -> {
+                    throw RendezvousError("Homeserver lacks support", RendezvousFailureReason.UnsupportedHomeserver)
+                }
+                FailureReason.CANCELLED -> {
+                    throw RendezvousError("Login cancelled by other device", RendezvousFailureReason.UserDeclined)
+                }
+                FailureReason.E2EE_SECURITY_ERROR -> {
+                    throw RendezvousError("E2EE security error", RendezvousFailureReason.E2EESecurityIssue)
+                }
+                // incompatible intent shouldn't be received at this stage
+                else -> {
+                    throw RendezvousError("Unknown error", RendezvousFailureReason.Unknown)
+                }
+            }
+        }
+
         val homeserver = loginToken?.homeserver ?: throw RendezvousError("No homeserver returned", RendezvousFailureReason.ProtocolError)
         val token = loginToken.loginToken ?: throw RendezvousError("No login token returned", RendezvousFailureReason.ProtocolError)
 
@@ -167,8 +216,11 @@ class Rendezvous(
         val crypto = session.cryptoService()
         val deviceId = crypto.getMyCryptoDevice().deviceId
         val deviceKey = crypto.getMyCryptoDevice().fingerprint()
-        send(Payload(PayloadType.PROGRESS, outcome = Outcome.SUCCESS, deviceId = deviceId, deviceKey = deviceKey))
-
+        if (isUsingV1()) {
+            send(Payload(PayloadType.PROGRESS, outcome = Outcome.SUCCESS, deviceId = deviceId, deviceKey = deviceKey))
+        } else {
+            send(Payload(PayloadType.SUCCESS, deviceId = deviceId, deviceKey = deviceKey))
+        }
         try {
             // explicitly download keys for ourself rather than racing with initial sync which might not complete in time
             crypto.downloadKeysIfNeeded(listOf(userId), false)
@@ -179,63 +231,78 @@ class Rendezvous(
 
         // await confirmation of verification
         val verificationResponse = receive()
-        if (verificationResponse?.outcome == Outcome.VERIFIED) {
+        if (verificationResponse?.outcome == Outcome.VERIFIED || verificationResponse?.type == PayloadType.VERIFIED) {
             val verifyingDeviceId = verificationResponse.verifyingDeviceId
                     ?: throw RendezvousError("No verifying device id returned", RendezvousFailureReason.ProtocolError)
-            val verifyingDeviceFromServer = crypto.getCryptoDeviceInfo(userId, verifyingDeviceId)
-            if (verifyingDeviceFromServer?.fingerprint() != verificationResponse.verifyingDeviceKey) {
-                Timber.tag(TAG).w(
-                        "Verifying device $verifyingDeviceId key doesn't match: ${
-                            verifyingDeviceFromServer?.fingerprint()
-                        } vs ${verificationResponse.verifyingDeviceKey})"
-                )
-                // inform the other side
-                send(Payload(PayloadType.FINISH, outcome = Outcome.E2EE_SECURITY_ERROR))
-                throw RendezvousError("Key from verifying device doesn't match", RendezvousFailureReason.E2EESecurityIssue)
-            }
-
-            verificationResponse.masterKey?.let { masterKeyFromVerifyingDevice ->
-                // verifying device provided us with a master key, so use it to check integrity
-
-                // see what the homeserver told us
-                val localMasterKey = crypto.crossSigningService().getMyCrossSigningKeys()?.masterKey()
-
-                // n.b. if no local master key this is a problem, as well as it not matching
-                if (localMasterKey?.unpaddedBase64PublicKey != masterKeyFromVerifyingDevice) {
-                    Timber.tag(TAG).w("Master key from verifying device doesn't match: $masterKeyFromVerifyingDevice vs $localMasterKey")
-                    // inform the other side
-                    send(Payload(PayloadType.FINISH, outcome = Outcome.E2EE_SECURITY_ERROR))
-                    throw RendezvousError("Master key from verifying device doesn't match", RendezvousFailureReason.E2EESecurityIssue)
-                }
-
-                // set other device as verified
-                Timber.tag(TAG).i("Setting device $verifyingDeviceId as verified")
-                crypto.setDeviceVerification(DeviceTrustLevel(locallyVerified = true, crossSigningVerified = false), userId, verifyingDeviceId)
-
-                Timber.tag(TAG).i("Setting master key as trusted")
-                crypto.crossSigningService().markMyMasterKeyAsTrusted()
-            } ?: run {
-                // set other device as verified anyway
-                Timber.tag(TAG).i("Setting device $verifyingDeviceId as verified")
-                crypto.setDeviceVerification(DeviceTrustLevel(locallyVerified = true, crossSigningVerified = false), userId, verifyingDeviceId)
-
-                Timber.tag(TAG).i("No master key given by verifying device")
-            }
-
-            // request secrets from the verifying device
-            Timber.tag(TAG).i("Requesting secrets from $verifyingDeviceId")
-
-            session.sharedSecretStorageService().let {
-                it.requestSecret(MASTER_KEY_SSSS_NAME, verifyingDeviceId)
-                it.requestSecret(SELF_SIGNING_KEY_SSSS_NAME, verifyingDeviceId)
-                it.requestSecret(USER_SIGNING_KEY_SSSS_NAME, verifyingDeviceId)
-                it.requestSecret(KEYBACKUP_SECRET_SSSS_NAME, verifyingDeviceId)
-            }
+            handleVerification(session, verifyingDeviceId, verificationResponse.verifyingDeviceKey, verificationResponse.masterKey)
         } else {
             Timber.tag(TAG).i("Not doing verification")
         }
     }
 
+    @Throws(RendezvousError::class)
+    private suspend fun handleVerification(session: Session, verifyingDeviceId: String, verifyingDeviceKey: String?, masterKey: String?) {
+        var crypto = session.cryptoService()
+        var userId = session.myUserId
+        val verifyingDeviceFromServer = crypto.getCryptoDeviceInfo(userId, verifyingDeviceId)
+        if (verifyingDeviceFromServer?.fingerprint() != verifyingDeviceKey) {
+            Timber.tag(TAG).w(
+                    "Verifying device $verifyingDeviceId key doesn't match: ${
+                        verifyingDeviceFromServer?.fingerprint()
+                    } vs $verifyingDeviceKey)"
+            )
+            // inform the other side
+            if (isUsingV1()) {
+                send(Payload(PayloadType.FINISH, outcome = Outcome.E2EE_SECURITY_ERROR))
+            } else {
+                send(Payload(PayloadType.FAILURE, reason = FailureReason.E2EE_SECURITY_ERROR))
+            }
+            throw RendezvousError("Key from verifying device doesn't match", RendezvousFailureReason.E2EESecurityIssue)
+        }
+
+        masterKey?.let { masterKeyFromVerifyingDevice ->
+            // verifying device provided us with a master key, so use it to check integrity
+
+            // see what the homeserver told us
+            val localMasterKey = crypto.crossSigningService().getMyCrossSigningKeys()?.masterKey()
+
+            // n.b. if no local master key this is a problem, as well as it not matching
+            if (localMasterKey?.unpaddedBase64PublicKey != masterKeyFromVerifyingDevice) {
+                Timber.tag(TAG).w("Master key from verifying device doesn't match: $masterKeyFromVerifyingDevice vs $localMasterKey")
+                // inform the other side
+                if (isUsingV1()) {
+                    send(Payload(PayloadType.FINISH, outcome = Outcome.E2EE_SECURITY_ERROR))
+                } else {
+                    send(Payload(PayloadType.FAILURE, reason = FailureReason.E2EE_SECURITY_ERROR))
+                }
+                throw RendezvousError("Master key from verifying device doesn't match", RendezvousFailureReason.E2EESecurityIssue)
+            }
+
+            // set other device as verified
+            Timber.tag(TAG).i("Setting device $verifyingDeviceId as verified")
+            crypto.setDeviceVerification(DeviceTrustLevel(locallyVerified = true, crossSigningVerified = false), userId, verifyingDeviceId)
+
+            Timber.tag(TAG).i("Setting master key as trusted")
+            crypto.crossSigningService().markMyMasterKeyAsTrusted()
+        } ?: run {
+            // set other device as verified anyway
+            Timber.tag(TAG).i("Setting device $verifyingDeviceId as verified")
+            crypto.setDeviceVerification(DeviceTrustLevel(locallyVerified = true, crossSigningVerified = false), userId, verifyingDeviceId)
+
+            Timber.tag(TAG).i("No master key given by verifying device")
+        }
+
+        // request secrets from the verifying device
+        Timber.tag(TAG).i("Requesting secrets from $verifyingDeviceId")
+
+        session.sharedSecretStorageService().let {
+            it.requestSecret(MASTER_KEY_SSSS_NAME, verifyingDeviceId)
+            it.requestSecret(SELF_SIGNING_KEY_SSSS_NAME, verifyingDeviceId)
+            it.requestSecret(USER_SIGNING_KEY_SSSS_NAME, verifyingDeviceId)
+            it.requestSecret(KEYBACKUP_SECRET_SSSS_NAME, verifyingDeviceId)
+        }
+    }
+
     @Throws(RendezvousError::class)
     private suspend fun receive(): Payload? {
         val data = channel.receive() ?: return null

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/rendezvous/channels/ECDHRendezvousChannel.kt

@@ -40,6 +40,8 @@ import javax.crypto.spec.SecretKeySpec
 /**
  *  Implements X25519 ECDH key agreement and AES-256-GCM encryption channel as per MSC3903:
  *  https://github.com/matrix-org/matrix-spec-proposals/pull/3903
+ *
+ * @alpha This is an experimental API, and is subject to change until MSC3903 is stabilised and accepted.
  */
 class ECDHRendezvousChannel(
         override var transport: RendezvousTransport,

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/rendezvous/model/ECDHRendezvousCode.kt

@@ -21,5 +21,6 @@ import com.squareup.moshi.JsonClass
 @JsonClass(generateAdapter = true)
 data class ECDHRendezvousCode(
         val intent: RendezvousIntent,
+        val flow: RendezvousFlow?,
         val rendezvous: ECDHRendezvous
 )

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/rendezvous/model/FailureReason.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2023 The Matrix.org Foundation C.I.C.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.matrix.android.sdk.api.rendezvous.model
+
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+
+@JsonClass(generateAdapter = false)
+enum class FailureReason(val value: String) {
+    @Json(name = "cancelled")
+    CANCELLED("cancelled"),
+
+    @Json(name = "unsupported")
+    UNSUPPORTED("unsupported"),
+
+    @Json(name = "e2ee_security_error")
+    E2EE_SECURITY_ERROR("e2ee_security_error"),
+
+    @Json(name = "incompatible_intent")
+    INCOMPATIBLE_INTENT("incompatible_intent")
+}

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/rendezvous/model/Outcome.kt

@@ -19,6 +19,9 @@ package org.matrix.android.sdk.api.rendezvous.model
 import com.squareup.moshi.Json
 import com.squareup.moshi.JsonClass
 
+/**
+ * This is only used for v1 of MSC3906 and will be removed in future. FailureReason is used in v2.
+ */
 @JsonClass(generateAdapter = false)
 enum class Outcome(val value: String) {
     @Json(name = "success")

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/rendezvous/model/Payload.kt

@@ -23,7 +23,11 @@ import com.squareup.moshi.JsonClass
 internal data class Payload(
         val type: PayloadType,
         val intent: RendezvousIntent? = null,
+        /**
+         * This is only used in v1 of MSC3906 and will be removed in future.
+         */
         val outcome: Outcome? = null,
+        val reason: FailureReason? = null,
         val protocols: List<Protocol>? = null,
         val protocol: Protocol? = null,
         val homeserver: String? = null,
@@ -32,5 +36,5 @@ internal data class Payload(
         @Json(name = "device_key") val deviceKey: String? = null,
         @Json(name = "verifying_device_id") val verifyingDeviceId: String? = null,
         @Json(name = "verifying_device_key") val verifyingDeviceKey: String? = null,
-        @Json(name = "master_key") val masterKey: String? = null
+        @Json(name = "master_key") val masterKey: String? = null,
 )

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/rendezvous/model/PayloadType.kt

@@ -21,12 +21,33 @@ import com.squareup.moshi.JsonClass
 
 @JsonClass(generateAdapter = false)
 internal enum class PayloadType(val value: String) {
-    @Json(name = "m.login.start")
-    START("m.login.start"),
-
+    /**
+     * This is only used in v1 of MSC3906 and will be removed in future.
+     */
     @Json(name = "m.login.finish")
     FINISH("m.login.finish"),
 
     @Json(name = "m.login.progress")
-    PROGRESS("m.login.progress")
+    PROGRESS("m.login.progress"),
+
+    @Json(name = "m.login.protocol")
+    PROTOCOL("m.login.protocol"),
+
+    @Json(name = "m.login.protocols")
+    PROTOCOLS("m.login.protocols"),
+
+    @Json(name = "m.login.approved")
+    APPROVED("m.login.approved"),
+
+    @Json(name = "m.login.success")
+    SUCCESS("m.login.success"),
+
+    @Json(name = "m.login.verified")
+    VERIFIED("m.login.verified"),
+
+    @Json(name = "m.login.failure")
+    FAILURE("m.login.failure"),
+
+    @Json(name = "m.login.declined")
+    DECLINED("m.login.declined"),
 }

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/rendezvous/model/RendezvousCode.kt

@@ -21,5 +21,6 @@ import com.squareup.moshi.JsonClass
 @JsonClass(generateAdapter = true)
 open class RendezvousCode(
         open val intent: RendezvousIntent,
+        open val flow: String?,
         open val rendezvous: Rendezvous
 )

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/rendezvous/model/RendezvousFlow.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2023 The Matrix.org Foundation C.I.C.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.matrix.android.sdk.api.rendezvous.model
+
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+
+@JsonClass(generateAdapter = false)
+enum class RendezvousFlow(val value: String) {
+    // v1 is never represented in JSON so we don't annotate it
+    SETUP_ADDITIONAL_DEVICE_V1("org.matrix.msc3906.v1"),
+    @Json(name = "org.matrix.msc3906.setup.additional_device.v2")
+    SETUP_ADDITIONAL_DEVICE_V2("org.matrix.msc3906.setup.additional_device.v2"),
+}

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/rendezvous/transports/SimpleHttpRendezvousTransport.kt

@@ -33,6 +33,8 @@ import java.util.Locale
 
 /**
  * Implementation of the Simple HTTP transport MSC3886: https://github.com/matrix-org/matrix-spec-proposals/pull/3886
+ *
+ * @alpha This is an experimental API, and is subject to change until MSC3886 is stabilised and accepted.
  */
 class SimpleHttpRendezvousTransport(rendezvousUri: String?) : RendezvousTransport {
     companion object {