Updated 30 files and deleted 2976 files (automated)

1 files changed, 0 insertions, 1496 deletions

diff --git a/includes/external/matrix/node_modules/matrix-js-sdk/src/crypto/OlmDevice.ts b/includes/external/matrix/node_modules/matrix-js-sdk/src/crypto/OlmDevice.ts
deleted file mode 100644
index 82a0a9a..0000000
--- a/includes/external/matrix/node_modules/matrix-js-sdk/src/crypto/OlmDevice.ts
+++ /dev/null
@@ -1,1496 +0,0 @@
-/*
-Copyright 2016 - 2021 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.
-*/
-
-import { Account, InboundGroupSession, OutboundGroupSession, Session, Utility } from "@matrix-org/olm";
-
-import { logger, PrefixedLogger } from "../logger";
-import { IndexedDBCryptoStore } from "./store/indexeddb-crypto-store";
-import * as algorithms from "./algorithms";
-import { CryptoStore, IProblem, ISessionInfo, IWithheld } from "./store/base";
-import { IOlmDevice, IOutboundGroupSessionKey } from "./algorithms/megolm";
-import { IMegolmSessionData, OlmGroupSessionExtraData } from "../@types/crypto";
-import { IMessage } from "./algorithms/olm";
-
-// The maximum size of an event is 65K, and we base64 the content, so this is a
-// reasonable approximation to the biggest plaintext we can encrypt.
-const MAX_PLAINTEXT_LENGTH = (65536 * 3) / 4;
-
-export class PayloadTooLargeError extends Error {
-    public readonly data = {
-        errcode: "M_TOO_LARGE",
-        error: "Payload too large for encrypted message",
-    };
-}
-
-function checkPayloadLength(payloadString: string): void {
-    if (payloadString === undefined) {
-        throw new Error("payloadString undefined");
-    }
-
-    if (payloadString.length > MAX_PLAINTEXT_LENGTH) {
-        // might as well fail early here rather than letting the olm library throw
-        // a cryptic memory allocation error.
-        //
-        // Note that even if we manage to do the encryption, the message send may fail,
-        // because by the time we've wrapped the ciphertext in the event object, it may
-        // exceed 65K. But at least we won't just fail with "abort()" in that case.
-        throw new PayloadTooLargeError(
-            `Message too long (${payloadString.length} bytes). ` +
-                `The maximum for an encrypted message is ${MAX_PLAINTEXT_LENGTH} bytes.`,
-        );
-    }
-}
-
-interface IInitOpts {
-    fromExportedDevice?: IExportedDevice;
-    pickleKey?: string;
-}
-
-/** data stored in the session store about an inbound group session */
-export interface InboundGroupSessionData {
-    room_id: string; // eslint-disable-line camelcase
-    /** pickled Olm.InboundGroupSession */
-    session: string;
-    keysClaimed: Record<string, string>;
-    /** Devices involved in forwarding this session to us (normally empty). */
-    forwardingCurve25519KeyChain: string[];
-    /** whether this session is untrusted. */
-    untrusted?: boolean;
-    /** whether this session exists during the room being set to shared history. */
-    sharedHistory?: boolean;
-}
-
-export interface IDecryptedGroupMessage {
-    result: string;
-    keysClaimed: Record<string, string>;
-    senderKey: string;
-    forwardingCurve25519KeyChain: string[];
-    untrusted: boolean;
-}
-
-export interface IInboundSession {
-    payload: string;
-    session_id: string;
-}
-
-export interface IExportedDevice {
-    pickleKey: string;
-    pickledAccount: string;
-    sessions: ISessionInfo[];
-}
-
-interface IUnpickledSessionInfo extends Omit<ISessionInfo, "session"> {
-    session: Session;
-}
-
-/* eslint-disable camelcase */
-interface IInboundGroupSessionKey {
-    chain_index: number;
-    key: string;
-    forwarding_curve25519_key_chain: string[];
-    sender_claimed_ed25519_key: string | null;
-    shared_history: boolean;
-    untrusted?: boolean;
-}
-/* eslint-enable camelcase */
-
-type OneTimeKeys = { curve25519: { [keyId: string]: string } };
-
-/**
- * Manages the olm cryptography functions. Each OlmDevice has a single
- * OlmAccount and a number of OlmSessions.
- *
- * Accounts and sessions are kept pickled in the cryptoStore.
- */
-export class OlmDevice {
-    public pickleKey = "DEFAULT_KEY"; // set by consumers
-
-    /** Curve25519 key for the account, unknown until we load the account from storage in init() */
-    public deviceCurve25519Key: string | null = null;
-    /** Ed25519 key for the account, unknown until we load the account from storage in init() */
-    public deviceEd25519Key: string | null = null;
-    private maxOneTimeKeys: number | null = null;
-
-    // we don't bother stashing outboundgroupsessions in the cryptoStore -
-    // instead we keep them here.
-    private outboundGroupSessionStore: Record<string, string> = {};
-
-    // Store a set of decrypted message indexes for each group session.
-    // This partially mitigates a replay attack where a MITM resends a group
-    // message into the room.
-    //
-    // When we decrypt a message and the message index matches a previously
-    // decrypted message, one possible cause of that is that we are decrypting
-    // the same event, and may not indicate an actual replay attack.  For
-    // example, this could happen if we receive events, forget about them, and
-    // then re-fetch them when we backfill.  So we store the event ID and
-    // timestamp corresponding to each message index when we first decrypt it,
-    // and compare these against the event ID and timestamp every time we use
-    // that same index.  If they match, then we're probably decrypting the same
-    // event and we don't consider it a replay attack.
-    //
-    // Keys are strings of form "<senderKey>|<session_id>|<message_index>"
-    // Values are objects of the form "{id: <event id>, timestamp: <ts>}"
-    private inboundGroupSessionMessageIndexes: Record<string, { id: string; timestamp: number }> = {};
-
-    // Keep track of sessions that we're starting, so that we don't start
-    // multiple sessions for the same device at the same time.
-    public sessionsInProgress: Record<string, Promise<void>> = {}; // set by consumers
-
-    // Used by olm to serialise prekey message decryptions
-    public olmPrekeyPromise: Promise<any> = Promise.resolve(); // set by consumers
-
-    public constructor(private readonly cryptoStore: CryptoStore) {}
-
-    /**
-     * @returns The version of Olm.
-     */
-    public static getOlmVersion(): [number, number, number] {
-        return global.Olm.get_library_version();
-    }
-
-    /**
-     * Initialise the OlmAccount. This must be called before any other operations
-     * on the OlmDevice.
-     *
-     * Data from an exported Olm device can be provided
-     * in order to re-create this device.
-     *
-     * Attempts to load the OlmAccount from the crypto store, or creates one if none is
-     * found.
-     *
-     * Reads the device keys from the OlmAccount object.
-     *
-     * @param fromExportedDevice - (Optional) data from exported device
-     *     that must be re-created.
-     *     If present, opts.pickleKey is ignored
-     *     (exported data already provides a pickle key)
-     * @param pickleKey - (Optional) pickle key to set instead of default one
-     */
-    public async init({ pickleKey, fromExportedDevice }: IInitOpts = {}): Promise<void> {
-        let e2eKeys;
-        const account = new global.Olm.Account();
-
-        try {
-            if (fromExportedDevice) {
-                if (pickleKey) {
-                    logger.warn("ignoring opts.pickleKey" + " because opts.fromExportedDevice is present.");
-                }
-                this.pickleKey = fromExportedDevice.pickleKey;
-                await this.initialiseFromExportedDevice(fromExportedDevice, account);
-            } else {
-                if (pickleKey) {
-                    this.pickleKey = pickleKey;
-                }
-                await this.initialiseAccount(account);
-            }
-            e2eKeys = JSON.parse(account.identity_keys());
-
-            this.maxOneTimeKeys = account.max_number_of_one_time_keys();
-        } finally {
-            account.free();
-        }
-
-        this.deviceCurve25519Key = e2eKeys.curve25519;
-        this.deviceEd25519Key = e2eKeys.ed25519;
-    }
-
-    /**
-     * Populates the crypto store using data that was exported from an existing device.
-     * Note that for now only the “account” and “sessions” stores are populated;
-     * Other stores will be as with a new device.
-     *
-     * @param exportedData - Data exported from another device
-     *     through the “export” method.
-     * @param account - an olm account to initialize
-     */
-    private async initialiseFromExportedDevice(exportedData: IExportedDevice, account: Account): Promise<void> {
-        await this.cryptoStore.doTxn(
-            "readwrite",
-            [IndexedDBCryptoStore.STORE_ACCOUNT, IndexedDBCryptoStore.STORE_SESSIONS],
-            (txn) => {
-                this.cryptoStore.storeAccount(txn, exportedData.pickledAccount);
-                exportedData.sessions.forEach((session) => {
-                    const { deviceKey, sessionId } = session;
-                    const sessionInfo = {
-                        session: session.session,
-                        lastReceivedMessageTs: session.lastReceivedMessageTs,
-                    };
-                    this.cryptoStore.storeEndToEndSession(deviceKey!, sessionId!, sessionInfo, txn);
-                });
-            },
-        );
-        account.unpickle(this.pickleKey, exportedData.pickledAccount);
-    }
-
-    private async initialiseAccount(account: Account): Promise<void> {
-        await this.cryptoStore.doTxn("readwrite", [IndexedDBCryptoStore.STORE_ACCOUNT], (txn) => {
-            this.cryptoStore.getAccount(txn, (pickledAccount) => {
-                if (pickledAccount !== null) {
-                    account.unpickle(this.pickleKey, pickledAccount);
-                } else {
-                    account.create();
-                    pickledAccount = account.pickle(this.pickleKey);
-                    this.cryptoStore.storeAccount(txn, pickledAccount);
-                }
-            });
-        });
-    }
-
-    /**
-     * extract our OlmAccount from the crypto store and call the given function
-     * with the account object
-     * The `account` object is usable only within the callback passed to this
-     * function and will be freed as soon the callback returns. It is *not*
-     * usable for the rest of the lifetime of the transaction.
-     * This function requires a live transaction object from cryptoStore.doTxn()
-     * and therefore may only be called in a doTxn() callback.
-     *
-     * @param txn - Opaque transaction object from cryptoStore.doTxn()
-     * @internal
-     */
-    private getAccount(txn: unknown, func: (account: Account) => void): void {
-        this.cryptoStore.getAccount(txn, (pickledAccount: string | null) => {
-            const account = new global.Olm.Account();
-            try {
-                account.unpickle(this.pickleKey, pickledAccount!);
-                func(account);
-            } finally {
-                account.free();
-            }
-        });
-    }
-
-    /*
-     * Saves an account to the crypto store.
-     * This function requires a live transaction object from cryptoStore.doTxn()
-     * and therefore may only be called in a doTxn() callback.
-     *
-     * @param txn - Opaque transaction object from cryptoStore.doTxn()
-     * @param Olm.Account object
-     * @internal
-     */
-    private storeAccount(txn: unknown, account: Account): void {
-        this.cryptoStore.storeAccount(txn, account.pickle(this.pickleKey));
-    }
-
-    /**
-     * Export data for re-creating the Olm device later.
-     * TODO export data other than just account and (P2P) sessions.
-     *
-     * @returns The exported data
-     */
-    public async export(): Promise<IExportedDevice> {
-        const result: Partial<IExportedDevice> = {
-            pickleKey: this.pickleKey,
-        };
-
-        await this.cryptoStore.doTxn(
-            "readonly",
-            [IndexedDBCryptoStore.STORE_ACCOUNT, IndexedDBCryptoStore.STORE_SESSIONS],
-            (txn) => {
-                this.cryptoStore.getAccount(txn, (pickledAccount: string | null) => {
-                    result.pickledAccount = pickledAccount!;
-                });
-                result.sessions = [];
-                // Note that the pickledSession object we get in the callback
-                // is not exactly the same thing you get in method _getSession
-                // see documentation of IndexedDBCryptoStore.getAllEndToEndSessions
-                this.cryptoStore.getAllEndToEndSessions(txn, (pickledSession) => {
-                    result.sessions!.push(pickledSession!);
-                });
-            },
-        );
-        return result as IExportedDevice;
-    }
-
-    /**
-     * extract an OlmSession from the session store and call the given function
-     * The session is usable only within the callback passed to this
-     * function and will be freed as soon the callback returns. It is *not*
-     * usable for the rest of the lifetime of the transaction.
-     *
-     * @param txn - Opaque transaction object from cryptoStore.doTxn()
-     * @internal
-     */
-    private getSession(
-        deviceKey: string,
-        sessionId: string,
-        txn: unknown,
-        func: (unpickledSessionInfo: IUnpickledSessionInfo) => void,
-    ): void {
-        this.cryptoStore.getEndToEndSession(deviceKey, sessionId, txn, (sessionInfo: ISessionInfo | null) => {
-            this.unpickleSession(sessionInfo!, func);
-        });
-    }
-
-    /**
-     * Creates a session object from a session pickle and executes the given
-     * function with it. The session object is destroyed once the function
-     * returns.
-     *
-     * @internal
-     */
-    private unpickleSession(
-        sessionInfo: ISessionInfo,
-        func: (unpickledSessionInfo: IUnpickledSessionInfo) => void,
-    ): void {
-        const session = new global.Olm.Session();
-        try {
-            session.unpickle(this.pickleKey, sessionInfo.session!);
-            const unpickledSessInfo: IUnpickledSessionInfo = Object.assign({}, sessionInfo, { session });
-
-            func(unpickledSessInfo);
-        } finally {
-            session.free();
-        }
-    }
-
-    /**
-     * store our OlmSession in the session store
-     *
-     * @param sessionInfo - `{session: OlmSession, lastReceivedMessageTs: int}`
-     * @param txn - Opaque transaction object from cryptoStore.doTxn()
-     * @internal
-     */
-    private saveSession(deviceKey: string, sessionInfo: IUnpickledSessionInfo, txn: unknown): void {
-        const sessionId = sessionInfo.session.session_id();
-        logger.debug(`Saving Olm session ${sessionId} with device ${deviceKey}: ${sessionInfo.session.describe()}`);
-
-        // Why do we re-use the input object for this, overwriting the same key with a different
-        // type? Is it because we want to erase the unpickled session to enforce that it's no longer
-        // used? A comment would be great.
-        const pickledSessionInfo = Object.assign(sessionInfo, {
-            session: sessionInfo.session.pickle(this.pickleKey),
-        });
-        this.cryptoStore.storeEndToEndSession(deviceKey, sessionId, pickledSessionInfo, txn);
-    }
-
-    /**
-     * get an OlmUtility and call the given function
-     *
-     * @returns result of func
-     * @internal
-     */
-    private getUtility<T>(func: (utility: Utility) => T): T {
-        const utility = new global.Olm.Utility();
-        try {
-            return func(utility);
-        } finally {
-            utility.free();
-        }
-    }
-
-    /**
-     * Signs a message with the ed25519 key for this account.
-     *
-     * @param message -  message to be signed
-     * @returns base64-encoded signature
-     */
-    public async sign(message: string): Promise<string> {
-        let result: string;
-        await this.cryptoStore.doTxn("readonly", [IndexedDBCryptoStore.STORE_ACCOUNT], (txn) => {
-            this.getAccount(txn, (account: Account) => {
-                result = account.sign(message);
-            });
-        });
-        return result!;
-    }
-
-    /**
-     * Get the current (unused, unpublished) one-time keys for this account.
-     *
-     * @returns one time keys; an object with the single property
-     * <tt>curve25519</tt>, which is itself an object mapping key id to Curve25519
-     * key.
-     */
-    public async getOneTimeKeys(): Promise<OneTimeKeys> {
-        let result: OneTimeKeys;
-        await this.cryptoStore.doTxn("readonly", [IndexedDBCryptoStore.STORE_ACCOUNT], (txn) => {
-            this.getAccount(txn, (account) => {
-                result = JSON.parse(account.one_time_keys());
-            });
-        });
-
-        return result!;
-    }
-
-    /**
-     * Get the maximum number of one-time keys we can store.
-     *
-     * @returns number of keys
-     */
-    public maxNumberOfOneTimeKeys(): number {
-        return this.maxOneTimeKeys ?? -1;
-    }
-
-    /**
-     * Marks all of the one-time keys as published.
-     */
-    public async markKeysAsPublished(): Promise<void> {
-        await this.cryptoStore.doTxn("readwrite", [IndexedDBCryptoStore.STORE_ACCOUNT], (txn) => {
-            this.getAccount(txn, (account: Account) => {
-                account.mark_keys_as_published();
-                this.storeAccount(txn, account);
-            });
-        });
-    }
-
-    /**
-     * Generate some new one-time keys
-     *
-     * @param numKeys - number of keys to generate
-     * @returns Resolved once the account is saved back having generated the keys
-     */
-    public generateOneTimeKeys(numKeys: number): Promise<void> {
-        return this.cryptoStore.doTxn("readwrite", [IndexedDBCryptoStore.STORE_ACCOUNT], (txn) => {
-            this.getAccount(txn, (account) => {
-                account.generate_one_time_keys(numKeys);
-                this.storeAccount(txn, account);
-            });
-        });
-    }
-
-    /**
-     * Generate a new fallback keys
-     *
-     * @returns Resolved once the account is saved back having generated the key
-     */
-    public async generateFallbackKey(): Promise<void> {
-        await this.cryptoStore.doTxn("readwrite", [IndexedDBCryptoStore.STORE_ACCOUNT], (txn) => {
-            this.getAccount(txn, (account) => {
-                account.generate_fallback_key();
-                this.storeAccount(txn, account);
-            });
-        });
-    }
-
-    public async getFallbackKey(): Promise<Record<string, Record<string, string>>> {
-        let result: Record<string, Record<string, string>>;
-        await this.cryptoStore.doTxn("readonly", [IndexedDBCryptoStore.STORE_ACCOUNT], (txn) => {
-            this.getAccount(txn, (account: Account) => {
-                result = JSON.parse(account.unpublished_fallback_key());
-            });
-        });
-        return result!;
-    }
-
-    public async forgetOldFallbackKey(): Promise<void> {
-        await this.cryptoStore.doTxn("readwrite", [IndexedDBCryptoStore.STORE_ACCOUNT], (txn) => {
-            this.getAccount(txn, (account: Account) => {
-                account.forget_old_fallback_key();
-                this.storeAccount(txn, account);
-            });
-        });
-    }
-
-    /**
-     * Generate a new outbound session
-     *
-     * The new session will be stored in the cryptoStore.
-     *
-     * @param theirIdentityKey - remote user's Curve25519 identity key
-     * @param theirOneTimeKey -  remote user's one-time Curve25519 key
-     * @returns sessionId for the outbound session.
-     */
-    public async createOutboundSession(theirIdentityKey: string, theirOneTimeKey: string): Promise<string> {
-        let newSessionId: string;
-        await this.cryptoStore.doTxn(
-            "readwrite",
-            [IndexedDBCryptoStore.STORE_ACCOUNT, IndexedDBCryptoStore.STORE_SESSIONS],
-            (txn) => {
-                this.getAccount(txn, (account: Account) => {
-                    const session = new global.Olm.Session();
-                    try {
-                        session.create_outbound(account, theirIdentityKey, theirOneTimeKey);
-                        newSessionId = session.session_id();
-                        this.storeAccount(txn, account);
-                        const sessionInfo: IUnpickledSessionInfo = {
-                            session,
-                            // Pretend we've received a message at this point, otherwise
-                            // if we try to send a message to the device, it won't use
-                            // this session
-                            lastReceivedMessageTs: Date.now(),
-                        };
-                        this.saveSession(theirIdentityKey, sessionInfo, txn);
-                    } finally {
-                        session.free();
-                    }
-                });
-            },
-            logger.withPrefix("[createOutboundSession]"),
-        );
-        return newSessionId!;
-    }
-
-    /**
-     * Generate a new inbound session, given an incoming message
-     *
-     * @param theirDeviceIdentityKey - remote user's Curve25519 identity key
-     * @param messageType -  messageType field from the received message (must be 0)
-     * @param ciphertext - base64-encoded body from the received message
-     *
-     * @returns decrypted payload, and
-     *     session id of new session
-     *
-     * @throws Error if the received message was not valid (for instance, it didn't use a valid one-time key).
-     */
-    public async createInboundSession(
-        theirDeviceIdentityKey: string,
-        messageType: number,
-        ciphertext: string,
-    ): Promise<IInboundSession> {
-        if (messageType !== 0) {
-            throw new Error("Need messageType == 0 to create inbound session");
-        }
-
-        let result: { payload: string; session_id: string }; // eslint-disable-line camelcase
-        await this.cryptoStore.doTxn(
-            "readwrite",
-            [IndexedDBCryptoStore.STORE_ACCOUNT, IndexedDBCryptoStore.STORE_SESSIONS],
-            (txn) => {
-                this.getAccount(txn, (account: Account) => {
-                    const session = new global.Olm.Session();
-                    try {
-                        session.create_inbound_from(account, theirDeviceIdentityKey, ciphertext);
-                        account.remove_one_time_keys(session);
-                        this.storeAccount(txn, account);
-
-                        const payloadString = session.decrypt(messageType, ciphertext);
-
-                        const sessionInfo: IUnpickledSessionInfo = {
-                            session,
-                            // this counts as a received message: set last received message time
-                            // to now
-                            lastReceivedMessageTs: Date.now(),
-                        };
-                        this.saveSession(theirDeviceIdentityKey, sessionInfo, txn);
-
-                        result = {
-                            payload: payloadString,
-                            session_id: session.session_id(),
-                        };
-                    } finally {
-                        session.free();
-                    }
-                });
-            },
-            logger.withPrefix("[createInboundSession]"),
-        );
-
-        return result!;
-    }
-
-    /**
-     * Get a list of known session IDs for the given device
-     *
-     * @param theirDeviceIdentityKey - Curve25519 identity key for the
-     *     remote device
-     * @returns  a list of known session ids for the device
-     */
-    public async getSessionIdsForDevice(theirDeviceIdentityKey: string): Promise<string[]> {
-        const log = logger.withPrefix("[getSessionIdsForDevice]");
-
-        if (theirDeviceIdentityKey in this.sessionsInProgress) {
-            log.debug(`Waiting for Olm session for ${theirDeviceIdentityKey} to be created`);
-            try {
-                await this.sessionsInProgress[theirDeviceIdentityKey];
-            } catch (e) {
-                // if the session failed to be created, just fall through and
-                // return an empty result
-            }
-        }
-        let sessionIds: string[];
-        await this.cryptoStore.doTxn(
-            "readonly",
-            [IndexedDBCryptoStore.STORE_SESSIONS],
-            (txn) => {
-                this.cryptoStore.getEndToEndSessions(theirDeviceIdentityKey, txn, (sessions) => {
-                    sessionIds = Object.keys(sessions);
-                });
-            },
-            log,
-        );
-
-        return sessionIds!;
-    }
-
-    /**
-     * Get the right olm session id for encrypting messages to the given identity key
-     *
-     * @param theirDeviceIdentityKey - Curve25519 identity key for the
-     *     remote device
-     * @param nowait - Don't wait for an in-progress session to complete.
-     *     This should only be set to true of the calling function is the function
-     *     that marked the session as being in-progress.
-     * @param log - A possibly customised log
-     * @returns  session id, or null if no established session
-     */
-    public async getSessionIdForDevice(
-        theirDeviceIdentityKey: string,
-        nowait = false,
-        log?: PrefixedLogger,
-    ): Promise<string | null> {
-        const sessionInfos = await this.getSessionInfoForDevice(theirDeviceIdentityKey, nowait, log);
-
-        if (sessionInfos.length === 0) {
-            return null;
-        }
-        // Use the session that has most recently received a message
-        let idxOfBest = 0;
-        for (let i = 1; i < sessionInfos.length; i++) {
-            const thisSessInfo = sessionInfos[i];
-            const thisLastReceived =
-                thisSessInfo.lastReceivedMessageTs === undefined ? 0 : thisSessInfo.lastReceivedMessageTs;
-
-            const bestSessInfo = sessionInfos[idxOfBest];
-            const bestLastReceived =
-                bestSessInfo.lastReceivedMessageTs === undefined ? 0 : bestSessInfo.lastReceivedMessageTs;
-            if (
-                thisLastReceived > bestLastReceived ||
-                (thisLastReceived === bestLastReceived && thisSessInfo.sessionId < bestSessInfo.sessionId)
-            ) {
-                idxOfBest = i;
-            }
-        }
-        return sessionInfos[idxOfBest].sessionId;
-    }
-
-    /**
-     * Get information on the active Olm sessions for a device.
-     * <p>
-     * Returns an array, with an entry for each active session. The first entry in
-     * the result will be the one used for outgoing messages. Each entry contains
-     * the keys 'hasReceivedMessage' (true if the session has received an incoming
-     * message and is therefore past the pre-key stage), and 'sessionId'.
-     *
-     * @param deviceIdentityKey - Curve25519 identity key for the device
-     * @param nowait - Don't wait for an in-progress session to complete.
-     *     This should only be set to true of the calling function is the function
-     *     that marked the session as being in-progress.
-     * @param log - A possibly customised log
-     */
-    public async getSessionInfoForDevice(
-        deviceIdentityKey: string,
-        nowait = false,
-        log = logger,
-    ): Promise<{ sessionId: string; lastReceivedMessageTs: number; hasReceivedMessage: boolean }[]> {
-        log = log.withPrefix("[getSessionInfoForDevice]");
-
-        if (deviceIdentityKey in this.sessionsInProgress && !nowait) {
-            log.debug(`Waiting for Olm session for ${deviceIdentityKey} to be created`);
-            try {
-                await this.sessionsInProgress[deviceIdentityKey];
-            } catch (e) {
-                // if the session failed to be created, then just fall through and
-                // return an empty result
-            }
-        }
-        const info: {
-            lastReceivedMessageTs: number;
-            hasReceivedMessage: boolean;
-            sessionId: string;
-        }[] = [];
-
-        await this.cryptoStore.doTxn(
-            "readonly",
-            [IndexedDBCryptoStore.STORE_SESSIONS],
-            (txn) => {
-                this.cryptoStore.getEndToEndSessions(deviceIdentityKey, txn, (sessions) => {
-                    const sessionIds = Object.keys(sessions).sort();
-                    for (const sessionId of sessionIds) {
-                        this.unpickleSession(sessions[sessionId], (sessInfo: IUnpickledSessionInfo) => {
-                            info.push({
-                                lastReceivedMessageTs: sessInfo.lastReceivedMessageTs!,
-                                hasReceivedMessage: sessInfo.session.has_received_message(),
-                                sessionId,
-                            });
-                        });
-                    }
-                });
-            },
-            log,
-        );
-
-        return info;
-    }
-
-    /**
-     * Encrypt an outgoing message using an existing session
-     *
-     * @param theirDeviceIdentityKey - Curve25519 identity key for the
-     *     remote device
-     * @param sessionId -  the id of the active session
-     * @param payloadString -  payload to be encrypted and sent
-     *
-     * @returns ciphertext
-     */
-    public async encryptMessage(
-        theirDeviceIdentityKey: string,
-        sessionId: string,
-        payloadString: string,
-    ): Promise<IMessage> {
-        checkPayloadLength(payloadString);
-
-        let res: IMessage;
-        await this.cryptoStore.doTxn(
-            "readwrite",
-            [IndexedDBCryptoStore.STORE_SESSIONS],
-            (txn) => {
-                this.getSession(theirDeviceIdentityKey, sessionId, txn, (sessionInfo) => {
-                    const sessionDesc = sessionInfo.session.describe();
-                    logger.log(
-                        "encryptMessage: Olm Session ID " +
-                            sessionId +
-                            " to " +
-                            theirDeviceIdentityKey +
-                            ": " +
-                            sessionDesc,
-                    );
-                    res = sessionInfo.session.encrypt(payloadString);
-                    this.saveSession(theirDeviceIdentityKey, sessionInfo, txn);
-                });
-            },
-            logger.withPrefix("[encryptMessage]"),
-        );
-        return res!;
-    }
-
-    /**
-     * Decrypt an incoming message using an existing session
-     *
-     * @param theirDeviceIdentityKey - Curve25519 identity key for the
-     *     remote device
-     * @param sessionId -  the id of the active session
-     * @param messageType -  messageType field from the received message
-     * @param ciphertext - base64-encoded body from the received message
-     *
-     * @returns decrypted payload.
-     */
-    public async decryptMessage(
-        theirDeviceIdentityKey: string,
-        sessionId: string,
-        messageType: number,
-        ciphertext: string,
-    ): Promise<string> {
-        let payloadString: string;
-        await this.cryptoStore.doTxn(
-            "readwrite",
-            [IndexedDBCryptoStore.STORE_SESSIONS],
-            (txn) => {
-                this.getSession(theirDeviceIdentityKey, sessionId, txn, (sessionInfo: IUnpickledSessionInfo) => {
-                    const sessionDesc = sessionInfo.session.describe();
-                    logger.log(
-                        "decryptMessage: Olm Session ID " +
-                            sessionId +
-                            " from " +
-                            theirDeviceIdentityKey +
-                            ": " +
-                            sessionDesc,
-                    );
-                    payloadString = sessionInfo.session.decrypt(messageType, ciphertext);
-                    sessionInfo.lastReceivedMessageTs = Date.now();
-                    this.saveSession(theirDeviceIdentityKey, sessionInfo, txn);
-                });
-            },
-            logger.withPrefix("[decryptMessage]"),
-        );
-        return payloadString!;
-    }
-
-    /**
-     * Determine if an incoming messages is a prekey message matching an existing session
-     *
-     * @param theirDeviceIdentityKey - Curve25519 identity key for the
-     *     remote device
-     * @param sessionId -  the id of the active session
-     * @param messageType -  messageType field from the received message
-     * @param ciphertext - base64-encoded body from the received message
-     *
-     * @returns true if the received message is a prekey message which matches
-     *    the given session.
-     */
-    public async matchesSession(
-        theirDeviceIdentityKey: string,
-        sessionId: string,
-        messageType: number,
-        ciphertext: string,
-    ): Promise<boolean> {
-        if (messageType !== 0) {
-            return false;
-        }
-
-        let matches: boolean;
-        await this.cryptoStore.doTxn(
-            "readonly",
-            [IndexedDBCryptoStore.STORE_SESSIONS],
-            (txn) => {
-                this.getSession(theirDeviceIdentityKey, sessionId, txn, (sessionInfo) => {
-                    matches = sessionInfo.session.matches_inbound(ciphertext);
-                });
-            },
-            logger.withPrefix("[matchesSession]"),
-        );
-        return matches!;
-    }
-
-    public async recordSessionProblem(deviceKey: string, type: string, fixed: boolean): Promise<void> {
-        logger.info(`Recording problem on olm session with ${deviceKey} of type ${type}. Recreating: ${fixed}`);
-        await this.cryptoStore.storeEndToEndSessionProblem(deviceKey, type, fixed);
-    }
-
-    public sessionMayHaveProblems(deviceKey: string, timestamp: number): Promise<IProblem | null> {
-        return this.cryptoStore.getEndToEndSessionProblem(deviceKey, timestamp);
-    }
-
-    public filterOutNotifiedErrorDevices(devices: IOlmDevice[]): Promise<IOlmDevice[]> {
-        return this.cryptoStore.filterOutNotifiedErrorDevices(devices);
-    }
-
-    // Outbound group session
-    // ======================
-
-    /**
-     * store an OutboundGroupSession in outboundGroupSessionStore
-     *
-     * @internal
-     */
-    private saveOutboundGroupSession(session: OutboundGroupSession): void {
-        this.outboundGroupSessionStore[session.session_id()] = session.pickle(this.pickleKey);
-    }
-
-    /**
-     * extract an OutboundGroupSession from outboundGroupSessionStore and call the
-     * given function
-     *
-     * @returns result of func
-     * @internal
-     */
-    private getOutboundGroupSession<T>(sessionId: string, func: (session: OutboundGroupSession) => T): T {
-        const pickled = this.outboundGroupSessionStore[sessionId];
-        if (pickled === undefined) {
-            throw new Error("Unknown outbound group session " + sessionId);
-        }
-
-        const session = new global.Olm.OutboundGroupSession();
-        try {
-            session.unpickle(this.pickleKey, pickled);
-            return func(session);
-        } finally {
-            session.free();
-        }
-    }
-
-    /**
-     * Generate a new outbound group session
-     *
-     * @returns sessionId for the outbound session.
-     */
-    public createOutboundGroupSession(): string {
-        const session = new global.Olm.OutboundGroupSession();
-        try {
-            session.create();
-            this.saveOutboundGroupSession(session);
-            return session.session_id();
-        } finally {
-            session.free();
-        }
-    }
-
-    /**
-     * Encrypt an outgoing message with an outbound group session
-     *
-     * @param sessionId -  the id of the outboundgroupsession
-     * @param payloadString -  payload to be encrypted and sent
-     *
-     * @returns ciphertext
-     */
-    public encryptGroupMessage(sessionId: string, payloadString: string): string {
-        logger.log(`encrypting msg with megolm session ${sessionId}`);
-
-        checkPayloadLength(payloadString);
-
-        return this.getOutboundGroupSession(sessionId, (session: OutboundGroupSession) => {
-            const res = session.encrypt(payloadString);
-            this.saveOutboundGroupSession(session);
-            return res;
-        });
-    }
-
-    /**
-     * Get the session keys for an outbound group session
-     *
-     * @param sessionId -  the id of the outbound group session
-     *
-     * @returns current chain index, and
-     *     base64-encoded secret key.
-     */
-    public getOutboundGroupSessionKey(sessionId: string): IOutboundGroupSessionKey {
-        return this.getOutboundGroupSession(sessionId, function (session: OutboundGroupSession) {
-            return {
-                chain_index: session.message_index(),
-                key: session.session_key(),
-            };
-        });
-    }
-
-    // Inbound group session
-    // =====================
-
-    /**
-     * Unpickle a session from a sessionData object and invoke the given function.
-     * The session is valid only until func returns.
-     *
-     * @param sessionData - Object describing the session.
-     * @param func - Invoked with the unpickled session
-     * @returns result of func
-     */
-    private unpickleInboundGroupSession<T>(
-        sessionData: InboundGroupSessionData,
-        func: (session: InboundGroupSession) => T,
-    ): T {
-        const session = new global.Olm.InboundGroupSession();
-        try {
-            session.unpickle(this.pickleKey, sessionData.session);
-            return func(session);
-        } finally {
-            session.free();
-        }
-    }
-
-    /**
-     * extract an InboundGroupSession from the crypto store and call the given function
-     *
-     * @param roomId - The room ID to extract the session for, or null to fetch
-     *     sessions for any room.
-     * @param txn - Opaque transaction object from cryptoStore.doTxn()
-     * @param func - function to call.
-     *
-     * @internal
-     */
-    private getInboundGroupSession(
-        roomId: string,
-        senderKey: string,
-        sessionId: string,
-        txn: unknown,
-        func: (
-            session: InboundGroupSession | null,
-            data: InboundGroupSessionData | null,
-            withheld: IWithheld | null,
-        ) => void,
-    ): void {
-        this.cryptoStore.getEndToEndInboundGroupSession(
-            senderKey,
-            sessionId,
-            txn,
-            (sessionData: InboundGroupSessionData | null, withheld: IWithheld | null) => {
-                if (sessionData === null) {
-                    func(null, null, withheld);
-                    return;
-                }
-
-                // if we were given a room ID, check that the it matches the original one for the session. This stops
-                // the HS pretending a message was targeting a different room.
-                if (roomId !== null && roomId !== sessionData.room_id) {
-                    throw new Error(
-                        "Mismatched room_id for inbound group session (expected " +
-                            sessionData.room_id +
-                            ", was " +
-                            roomId +
-                            ")",
-                    );
-                }
-
-                this.unpickleInboundGroupSession(sessionData, (session: InboundGroupSession) => {
-                    func(session, sessionData, withheld);
-                });
-            },
-        );
-    }
-
-    /**
-     * Add an inbound group session to the session store
-     *
-     * @param roomId -     room in which this session will be used
-     * @param senderKey -  base64-encoded curve25519 key of the sender
-     * @param forwardingCurve25519KeyChain -  Devices involved in forwarding
-     *     this session to us.
-     * @param sessionId -  session identifier
-     * @param sessionKey - base64-encoded secret key
-     * @param keysClaimed - Other keys the sender claims.
-     * @param exportFormat - true if the megolm keys are in export format
-     *    (ie, they lack an ed25519 signature)
-     * @param extraSessionData - any other data to be include with the session
-     */
-    public async addInboundGroupSession(
-        roomId: string,
-        senderKey: string,
-        forwardingCurve25519KeyChain: string[],
-        sessionId: string,
-        sessionKey: string,
-        keysClaimed: Record<string, string>,
-        exportFormat: boolean,
-        extraSessionData: OlmGroupSessionExtraData = {},
-    ): Promise<void> {
-        await this.cryptoStore.doTxn(
-            "readwrite",
-            [
-                IndexedDBCryptoStore.STORE_INBOUND_GROUP_SESSIONS,
-                IndexedDBCryptoStore.STORE_INBOUND_GROUP_SESSIONS_WITHHELD,
-                IndexedDBCryptoStore.STORE_SHARED_HISTORY_INBOUND_GROUP_SESSIONS,
-            ],
-            (txn) => {
-                /* if we already have this session, consider updating it */
-                this.getInboundGroupSession(
-                    roomId,
-                    senderKey,
-                    sessionId,
-                    txn,
-                    (
-                        existingSession: InboundGroupSession | null,
-                        existingSessionData: InboundGroupSessionData | null,
-                    ) => {
-                        // new session.
-                        const session = new global.Olm.InboundGroupSession();
-                        try {
-                            if (exportFormat) {
-                                session.import_session(sessionKey);
-                            } else {
-                                session.create(sessionKey);
-                            }
-                            if (sessionId != session.session_id()) {
-                                throw new Error("Mismatched group session ID from senderKey: " + senderKey);
-                            }
-
-                            if (existingSession) {
-                                logger.log(`Update for megolm session ${senderKey}|${sessionId}`);
-                                if (existingSession.first_known_index() <= session.first_known_index()) {
-                                    if (!existingSessionData!.untrusted || extraSessionData.untrusted) {
-                                        // existing session has less-than-or-equal index
-                                        // (i.e. can decrypt at least as much), and the
-                                        // new session's trust does not win over the old
-                                        // session's trust, so keep it
-                                        logger.log(`Keeping existing megolm session ${senderKey}|${sessionId}`);
-                                        return;
-                                    }
-                                    if (existingSession.first_known_index() < session.first_known_index()) {
-                                        // We want to upgrade the existing session's trust,
-                                        // but we can't just use the new session because we'll
-                                        // lose the lower index. Check that the sessions connect
-                                        // properly, and then manually set the existing session
-                                        // as trusted.
-                                        if (
-                                            existingSession.export_session(session.first_known_index()) ===
-                                            session.export_session(session.first_known_index())
-                                        ) {
-                                            logger.info(
-                                                "Upgrading trust of existing megolm session " +
-                                                    `${senderKey}|${sessionId} based on newly-received trusted session`,
-                                            );
-                                            existingSessionData!.untrusted = false;
-                                            this.cryptoStore.storeEndToEndInboundGroupSession(
-                                                senderKey,
-                                                sessionId,
-                                                existingSessionData!,
-                                                txn,
-                                            );
-                                        } else {
-                                            logger.warn(
-                                                `Newly-received megolm session ${senderKey}|$sessionId}` +
-                                                    " does not match existing session! Keeping existing session",
-                                            );
-                                        }
-                                        return;
-                                    }
-                                    // If the sessions have the same index, go ahead and store the new trusted one.
-                                }
-                            }
-
-                            logger.info(
-                                `Storing megolm session ${senderKey}|${sessionId} with first index ` +
-                                    session.first_known_index(),
-                            );
-
-                            const sessionData = Object.assign({}, extraSessionData, {
-                                room_id: roomId,
-                                session: session.pickle(this.pickleKey),
-                                keysClaimed: keysClaimed,
-                                forwardingCurve25519KeyChain: forwardingCurve25519KeyChain,
-                            });
-
-                            this.cryptoStore.storeEndToEndInboundGroupSession(senderKey, sessionId, sessionData, txn);
-
-                            if (!existingSession && extraSessionData.sharedHistory) {
-                                this.cryptoStore.addSharedHistoryInboundGroupSession(roomId, senderKey, sessionId, txn);
-                            }
-                        } finally {
-                            session.free();
-                        }
-                    },
-                );
-            },
-            logger.withPrefix("[addInboundGroupSession]"),
-        );
-    }
-
-    /**
-     * Record in the data store why an inbound group session was withheld.
-     *
-     * @param roomId -     room that the session belongs to
-     * @param senderKey -  base64-encoded curve25519 key of the sender
-     * @param sessionId -  session identifier
-     * @param code -       reason code
-     * @param reason -     human-readable version of `code`
-     */
-    public async addInboundGroupSessionWithheld(
-        roomId: string,
-        senderKey: string,
-        sessionId: string,
-        code: string,
-        reason: string,
-    ): Promise<void> {
-        await this.cryptoStore.doTxn(
-            "readwrite",
-            [IndexedDBCryptoStore.STORE_INBOUND_GROUP_SESSIONS_WITHHELD],
-            (txn) => {
-                this.cryptoStore.storeEndToEndInboundGroupSessionWithheld(
-                    senderKey,
-                    sessionId,
-                    {
-                        room_id: roomId,
-                        code: code,
-                        reason: reason,
-                    },
-                    txn,
-                );
-            },
-        );
-    }
-
-    /**
-     * Decrypt a received message with an inbound group session
-     *
-     * @param roomId -    room in which the message was received
-     * @param senderKey - base64-encoded curve25519 key of the sender
-     * @param sessionId - session identifier
-     * @param body -      base64-encoded body of the encrypted message
-     * @param eventId -   ID of the event being decrypted
-     * @param timestamp - timestamp of the event being decrypted
-     *
-     * @returns null if the sessionId is unknown
-     */
-    public async decryptGroupMessage(
-        roomId: string,
-        senderKey: string,
-        sessionId: string,
-        body: string,
-        eventId: string,
-        timestamp: number,
-    ): Promise<IDecryptedGroupMessage | null> {
-        let result: IDecryptedGroupMessage | null = null;
-        // when the localstorage crypto store is used as an indexeddb backend,
-        // exceptions thrown from within the inner function are not passed through
-        // to the top level, so we store exceptions in a variable and raise them at
-        // the end
-        let error: Error;
-
-        await this.cryptoStore.doTxn(
-            "readwrite",
-            [
-                IndexedDBCryptoStore.STORE_INBOUND_GROUP_SESSIONS,
-                IndexedDBCryptoStore.STORE_INBOUND_GROUP_SESSIONS_WITHHELD,
-            ],
-            (txn) => {
-                this.getInboundGroupSession(roomId, senderKey, sessionId, txn, (session, sessionData, withheld) => {
-                    if (session === null || sessionData === null) {
-                        if (withheld) {
-                            error = new algorithms.DecryptionError(
-                                "MEGOLM_UNKNOWN_INBOUND_SESSION_ID",
-                                calculateWithheldMessage(withheld),
-                                {
-                                    session: senderKey + "|" + sessionId,
-                                },
-                            );
-                        }
-                        result = null;
-                        return;
-                    }
-                    let res: ReturnType<InboundGroupSession["decrypt"]>;
-                    try {
-                        res = session.decrypt(body);
-                    } catch (e) {
-                        if ((<Error>e)?.message === "OLM.UNKNOWN_MESSAGE_INDEX" && withheld) {
-                            error = new algorithms.DecryptionError(
-                                "MEGOLM_UNKNOWN_INBOUND_SESSION_ID",
-                                calculateWithheldMessage(withheld),
-                                {
-                                    session: senderKey + "|" + sessionId,
-                                },
-                            );
-                        } else {
-                            error = <Error>e;
-                        }
-                        return;
-                    }
-
-                    let plaintext: string = res.plaintext;
-                    if (plaintext === undefined) {
-                        // @ts-ignore - Compatibility for older olm versions.
-                        plaintext = res as string;
-                    } else {
-                        // Check if we have seen this message index before to detect replay attacks.
-                        // If the event ID and timestamp are specified, and the match the event ID
-                        // and timestamp from the last time we used this message index, then we
-                        // don't consider it a replay attack.
-                        const messageIndexKey = senderKey + "|" + sessionId + "|" + res.message_index;
-                        if (messageIndexKey in this.inboundGroupSessionMessageIndexes) {
-                            const msgInfo = this.inboundGroupSessionMessageIndexes[messageIndexKey];
-                            if (msgInfo.id !== eventId || msgInfo.timestamp !== timestamp) {
-                                error = new Error(
-                                    "Duplicate message index, possible replay attack: " + messageIndexKey,
-                                );
-                                return;
-                            }
-                        }
-                        this.inboundGroupSessionMessageIndexes[messageIndexKey] = {
-                            id: eventId,
-                            timestamp: timestamp,
-                        };
-                    }
-
-                    sessionData.session = session.pickle(this.pickleKey);
-                    this.cryptoStore.storeEndToEndInboundGroupSession(senderKey, sessionId, sessionData, txn);
-                    result = {
-                        result: plaintext,
-                        keysClaimed: sessionData.keysClaimed || {},
-                        senderKey: senderKey,
-                        forwardingCurve25519KeyChain: sessionData.forwardingCurve25519KeyChain || [],
-                        untrusted: !!sessionData.untrusted,
-                    };
-                });
-            },
-            logger.withPrefix("[decryptGroupMessage]"),
-        );
-
-        if (error!) {
-            throw error;
-        }
-        return result!;
-    }
-
-    /**
-     * Determine if we have the keys for a given megolm session
-     *
-     * @param roomId -    room in which the message was received
-     * @param senderKey - base64-encoded curve25519 key of the sender
-     * @param sessionId - session identifier
-     *
-     * @returns true if we have the keys to this session
-     */
-    public async hasInboundSessionKeys(roomId: string, senderKey: string, sessionId: string): Promise<boolean> {
-        let result: boolean;
-        await this.cryptoStore.doTxn(
-            "readonly",
-            [
-                IndexedDBCryptoStore.STORE_INBOUND_GROUP_SESSIONS,
-                IndexedDBCryptoStore.STORE_INBOUND_GROUP_SESSIONS_WITHHELD,
-            ],
-            (txn) => {
-                this.cryptoStore.getEndToEndInboundGroupSession(senderKey, sessionId, txn, (sessionData) => {
-                    if (sessionData === null) {
-                        result = false;
-                        return;
-                    }
-
-                    if (roomId !== sessionData.room_id) {
-                        logger.warn(
-                            `requested keys for inbound group session ${senderKey}|` +
-                                `${sessionId}, with incorrect room_id ` +
-                                `(expected ${sessionData.room_id}, ` +
-                                `was ${roomId})`,
-                        );
-                        result = false;
-                    } else {
-                        result = true;
-                    }
-                });
-            },
-            logger.withPrefix("[hasInboundSessionKeys]"),
-        );
-
-        return result!;
-    }
-
-    /**
-     * Extract the keys to a given megolm session, for sharing
-     *
-     * @param roomId -    room in which the message was received
-     * @param senderKey - base64-encoded curve25519 key of the sender
-     * @param sessionId - session identifier
-     * @param chainIndex - The chain index at which to export the session.
-     *     If omitted, export at the first index we know about.
-     *
-     * @returns
-     *    details of the session key. The key is a base64-encoded megolm key in
-     *    export format.
-     *
-     * @throws Error If the given chain index could not be obtained from the known
-     *     index (ie. the given chain index is before the first we have).
-     */
-    public async getInboundGroupSessionKey(
-        roomId: string,
-        senderKey: string,
-        sessionId: string,
-        chainIndex?: number,
-    ): Promise<IInboundGroupSessionKey | null> {
-        let result: IInboundGroupSessionKey | null = null;
-        await this.cryptoStore.doTxn(
-            "readonly",
-            [
-                IndexedDBCryptoStore.STORE_INBOUND_GROUP_SESSIONS,
-                IndexedDBCryptoStore.STORE_INBOUND_GROUP_SESSIONS_WITHHELD,
-            ],
-            (txn) => {
-                this.getInboundGroupSession(roomId, senderKey, sessionId, txn, (session, sessionData) => {
-                    if (session === null || sessionData === null) {
-                        result = null;
-                        return;
-                    }
-
-                    if (chainIndex === undefined) {
-                        chainIndex = session.first_known_index();
-                    }
-
-                    const exportedSession = session.export_session(chainIndex);
-
-                    const claimedKeys = sessionData.keysClaimed || {};
-                    const senderEd25519Key = claimedKeys.ed25519 || null;
-
-                    const forwardingKeyChain = sessionData.forwardingCurve25519KeyChain || [];
-                    // older forwarded keys didn't set the "untrusted"
-                    // property, but can be identified by having a
-                    // non-empty forwarding key chain.  These keys should
-                    // be marked as untrusted since we don't know that they
-                    // can be trusted
-                    const untrusted =
-                        "untrusted" in sessionData ? sessionData.untrusted : forwardingKeyChain.length > 0;
-
-                    result = {
-                        chain_index: chainIndex,
-                        key: exportedSession,
-                        forwarding_curve25519_key_chain: forwardingKeyChain,
-                        sender_claimed_ed25519_key: senderEd25519Key,
-                        shared_history: sessionData.sharedHistory || false,
-                        untrusted: untrusted,
-                    };
-                });
-            },
-            logger.withPrefix("[getInboundGroupSessionKey]"),
-        );
-
-        return result;
-    }
-
-    /**
-     * Export an inbound group session
-     *
-     * @param senderKey - base64-encoded curve25519 key of the sender
-     * @param sessionId - session identifier
-     * @param sessionData - The session object from the store
-     * @returns exported session data
-     */
-    public exportInboundGroupSession(
-        senderKey: string,
-        sessionId: string,
-        sessionData: InboundGroupSessionData,
-    ): IMegolmSessionData {
-        return this.unpickleInboundGroupSession(sessionData, (session) => {
-            const messageIndex = session.first_known_index();
-
-            return {
-                "sender_key": senderKey,
-                "sender_claimed_keys": sessionData.keysClaimed,
-                "room_id": sessionData.room_id,
-                "session_id": sessionId,
-                "session_key": session.export_session(messageIndex),
-                "forwarding_curve25519_key_chain": sessionData.forwardingCurve25519KeyChain || [],
-                "first_known_index": session.first_known_index(),
-                "org.matrix.msc3061.shared_history": sessionData.sharedHistory || false,
-            } as IMegolmSessionData;
-        });
-    }
-
-    public async getSharedHistoryInboundGroupSessions(
-        roomId: string,
-    ): Promise<[senderKey: string, sessionId: string][]> {
-        let result: Promise<[senderKey: string, sessionId: string][]>;
-        await this.cryptoStore.doTxn(
-            "readonly",
-            [IndexedDBCryptoStore.STORE_SHARED_HISTORY_INBOUND_GROUP_SESSIONS],
-            (txn) => {
-                result = this.cryptoStore.getSharedHistoryInboundGroupSessions(roomId, txn);
-            },
-            logger.withPrefix("[getSharedHistoryInboundGroupSessionsForRoom]"),
-        );
-        return result!;
-    }
-
-    // Utilities
-    // =========
-
-    /**
-     * Verify an ed25519 signature.
-     *
-     * @param key - ed25519 key
-     * @param message - message which was signed
-     * @param signature - base64-encoded signature to be checked
-     *
-     * @throws Error if there is a problem with the verification. If the key was
-     * too small then the message will be "OLM.INVALID_BASE64". If the signature
-     * was invalid then the message will be "OLM.BAD_MESSAGE_MAC".
-     */
-    public verifySignature(key: string, message: string, signature: string): void {
-        this.getUtility(function (util: Utility) {
-            util.ed25519_verify(key, message, signature);
-        });
-    }
-}
-
-export const WITHHELD_MESSAGES: Record<string, string> = {
-    "m.unverified": "The sender has disabled encrypting to unverified devices.",
-    "m.blacklisted": "The sender has blocked you.",
-    "m.unauthorised": "You are not authorised to read the message.",
-    "m.no_olm": "Unable to establish a secure channel.",
-};
-
-/**
- * Calculate the message to use for the exception when a session key is withheld.
- *
- * @param withheld -  An object that describes why the key was withheld.
- *
- * @returns the message
- *
- * @internal
- */
-function calculateWithheldMessage(withheld: IWithheld): string {
-    if (withheld.code && withheld.code in WITHHELD_MESSAGES) {
-        return WITHHELD_MESSAGES[withheld.code];
-    } else if (withheld.reason) {
-        return withheld.reason;
-    } else {
-        return "decryption key withheld";
-    }
-}