diff --git a/crypto/verificationhelper/reciprocate.go b/crypto/verificationhelper/reciprocate.go
index 395775e1..21276218 100644
--- a/crypto/verificationhelper/reciprocate.go
+++ b/crypto/verificationhelper/reciprocate.go
@@ -35,13 +35,13 @@ func (vh *VerificationHelper) HandleScannedQRData(ctx context.Context, data []by
 	vh.activeTransactionsLock.Lock()
 	defer vh.activeTransactionsLock.Unlock()
 
-	txn, err := vh.store.GetVerificationTransaction(ctx, qrCode.TransactionID)
-	if err != nil {
-		return fmt.Errorf("failed to get transaction %s: %w", qrCode.TransactionID, err)
-	} else if txn.VerificationState != VerificationStateReady {
+	txn, ok := vh.activeTransactions[qrCode.TransactionID]
+	if !ok {
+		return fmt.Errorf("unknown transaction ID found in QR code")
+	} else if txn.VerificationState != verificationStateReady {
 		return vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUnexpectedMessage, "transaction found in the QR code is not in the ready state")
 	}
-	txn.VerificationState = VerificationStateTheirQRScanned
+	txn.VerificationState = verificationStateTheirQRScanned
 
 	// Verify the keys
 	log.Info().Msg("Verifying keys from QR code")
@@ -53,9 +53,9 @@ func (vh *VerificationHelper) HandleScannedQRData(ctx context.Context, data []by
 
 	switch qrCode.Mode {
 	case QRCodeModeCrossSigning:
-		theirSigningKeys, err := vh.mach.GetCrossSigningPublicKeys(ctx, txn.TheirUserID)
+		theirSigningKeys, err := vh.mach.GetCrossSigningPublicKeys(ctx, txn.TheirUser)
 		if err != nil {
-			return vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeKeyMismatch, "couldn't get %s's cross-signing keys: %w", txn.TheirUserID, err)
+			return vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeKeyMismatch, "couldn't get %s's cross-signing keys: %w", txn.TheirUser, err)
 		}
 		if bytes.Equal(theirSigningKeys.MasterKey.Bytes(), qrCode.Key1[:]) {
 			log.Info().Msg("Verified that the other device has the master key we expected")
@@ -70,7 +70,7 @@ func (vh *VerificationHelper) HandleScannedQRData(ctx context.Context, data []by
 			return vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeKeyMismatch, "the master key does not match")
 		}
 
-		if err := vh.mach.SignUser(ctx, txn.TheirUserID, theirSigningKeys.MasterKey); err != nil {
+		if err := vh.mach.SignUser(ctx, txn.TheirUser, theirSigningKeys.MasterKey); err != nil {
 			return vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeInternalError, "failed to sign their master key: %w", err)
 		}
 	case QRCodeModeSelfVerifyingMasterKeyTrusted:
@@ -78,7 +78,7 @@ func (vh *VerificationHelper) HandleScannedQRData(ctx context.Context, data []by
 		// means that we don't trust the key. Key1 is the master key public
 		// key, and Key2 is what the other device thinks our device key is.
 
-		if vh.client.UserID != txn.TheirUserID {
+		if vh.client.UserID != txn.TheirUser {
 			return vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUnexpectedMessage, "mode %d is only allowed when the other user is the same as the current user", qrCode.Mode)
 		}
 
@@ -114,12 +114,12 @@ func (vh *VerificationHelper) HandleScannedQRData(ctx context.Context, data []by
 			return vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeMasterKeyNotTrusted, "the master key is not trusted by this device, cannot verify device that does not trust the master key")
 		}
 
-		if vh.client.UserID != txn.TheirUserID {
+		if vh.client.UserID != txn.TheirUser {
 			return vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUnexpectedMessage, "mode %d is only allowed when the other user is the same as the current user", qrCode.Mode)
 		}
 
 		// Get their device
-		theirDevice, err := vh.mach.GetOrFetchDevice(ctx, txn.TheirUserID, txn.TheirDeviceID)
+		theirDevice, err := vh.mach.GetOrFetchDevice(ctx, txn.TheirUser, txn.TheirDevice)
 		if err != nil {
 			return vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeInternalError, "failed to get their device: %w", err)
 		}
@@ -140,7 +140,7 @@ func (vh *VerificationHelper) HandleScannedQRData(ctx context.Context, data []by
 
 		// Trust their device
 		theirDevice.Trust = id.TrustStateVerified
-		err = vh.mach.CryptoStore.PutDevice(ctx, txn.TheirUserID, theirDevice)
+		err = vh.mach.CryptoStore.PutDevice(ctx, txn.TheirUser, theirDevice)
 		if err != nil {
 			return vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeInternalError, "failed to update device trust state after verifying: %+v", err)
 		}
@@ -177,12 +177,8 @@ func (vh *VerificationHelper) HandleScannedQRData(ctx context.Context, data []by
 	txn.SentOurDone = true
 	if txn.ReceivedTheirDone {
 		log.Debug().Msg("We already received their done event. Setting verification state to done.")
-		if err = vh.store.DeleteVerification(ctx, txn.TransactionID); err != nil {
-			return err
-		}
+		delete(vh.activeTransactions, txn.TransactionID)
 		vh.verificationDone(ctx, txn.TransactionID)
-	} else {
-		vh.store.SaveVerificationTransaction(ctx, txn)
 	}
 	return nil
 }
@@ -200,27 +196,28 @@ func (vh *VerificationHelper) ConfirmQRCodeScanned(ctx context.Context, txnID id
 
 	vh.activeTransactionsLock.Lock()
 	defer vh.activeTransactionsLock.Unlock()
-	txn, err := vh.store.GetVerificationTransaction(ctx, txnID)
-	if err != nil {
-		return fmt.Errorf("failed to get transaction %s: %w", txnID, err)
-	} else if txn.VerificationState != VerificationStateOurQRScanned {
+	txn, ok := vh.activeTransactions[txnID]
+	if !ok {
+		log.Warn().Msg("Ignoring QR code scan confirmation for an unknown transaction")
+		return nil
+	} else if txn.VerificationState != verificationStateOurQRScanned {
 		return fmt.Errorf("transaction is not in the scanned state")
 	}
 
 	log.Info().Msg("Confirming QR code scanned")
 
-	if txn.TheirUserID == vh.client.UserID {
+	if txn.TheirUser == vh.client.UserID {
 		// Self-signing situation. Trust their device.
 
 		// Get their device
-		theirDevice, err := vh.mach.GetOrFetchDevice(ctx, txn.TheirUserID, txn.TheirDeviceID)
+		theirDevice, err := vh.mach.GetOrFetchDevice(ctx, txn.TheirUser, txn.TheirDevice)
 		if err != nil {
 			return err
 		}
 
 		// Trust their device
 		theirDevice.Trust = id.TrustStateVerified
-		err = vh.mach.CryptoStore.PutDevice(ctx, txn.TheirUserID, theirDevice)
+		err = vh.mach.CryptoStore.PutDevice(ctx, txn.TheirUser, theirDevice)
 		if err != nil {
 			return fmt.Errorf("failed to update device trust state after verifying: %w", err)
 		}
@@ -234,33 +231,29 @@ func (vh *VerificationHelper) ConfirmQRCodeScanned(ctx context.Context, txnID id
 		}
 	} else {
 		// Cross-signing situation. Sign their master key.
-		theirSigningKeys, err := vh.mach.GetCrossSigningPublicKeys(ctx, txn.TheirUserID)
+		theirSigningKeys, err := vh.mach.GetCrossSigningPublicKeys(ctx, txn.TheirUser)
 		if err != nil {
-			return vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeKeyMismatch, "couldn't get %s's cross-signing keys: %w", txn.TheirUserID, err)
+			return vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeKeyMismatch, "couldn't get %s's cross-signing keys: %w", txn.TheirUser, err)
 		}
 
-		if err := vh.mach.SignUser(ctx, txn.TheirUserID, theirSigningKeys.MasterKey); err != nil {
+		if err := vh.mach.SignUser(ctx, txn.TheirUser, theirSigningKeys.MasterKey); err != nil {
 			return vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeInternalError, "failed to sign their master key: %w", err)
 		}
 	}
 
-	err = vh.sendVerificationEvent(ctx, txn, event.InRoomVerificationDone, &event.VerificationDoneEventContent{})
+	err := vh.sendVerificationEvent(ctx, txn, event.InRoomVerificationDone, &event.VerificationDoneEventContent{})
 	if err != nil {
 		return err
 	}
 	txn.SentOurDone = true
 	if txn.ReceivedTheirDone {
-		if err = vh.store.DeleteVerification(ctx, txn.TransactionID); err != nil {
-			return err
-		}
+		delete(vh.activeTransactions, txn.TransactionID)
 		vh.verificationDone(ctx, txn.TransactionID)
-	} else {
-		vh.store.SaveVerificationTransaction(ctx, txn)
 	}
 	return nil
 }
 
-func (vh *VerificationHelper) generateAndShowQRCode(ctx context.Context, txn VerificationTransaction) error {
+func (vh *VerificationHelper) generateAndShowQRCode(ctx context.Context, txn *verificationTransaction) error {
 	log := vh.getLog(ctx).With().
 		Str("verification_action", "generate and show QR code").
 		Stringer("transaction_id", txn.TransactionID).
@@ -283,7 +276,7 @@ func (vh *VerificationHelper) generateAndShowQRCode(ctx context.Context, txn Ver
 		return err
 	}
 	mode := QRCodeModeCrossSigning
-	if vh.client.UserID == txn.TheirUserID {
+	if vh.client.UserID == txn.TheirUser {
 		// This is a self-signing situation.
 		if ownMasterKeyTrusted {
 			mode = QRCodeModeSelfVerifyingMasterKeyTrusted
@@ -305,7 +298,7 @@ func (vh *VerificationHelper) generateAndShowQRCode(ctx context.Context, txn Ver
 		key1 = ownCrossSigningPublicKeys.MasterKey.Bytes()
 
 		// Key 2 is the other user's master signing key.
-		theirSigningKeys, err := vh.mach.GetCrossSigningPublicKeys(ctx, txn.TheirUserID)
+		theirSigningKeys, err := vh.mach.GetCrossSigningPublicKeys(ctx, txn.TheirUser)
 		if err != nil {
 			return err
 		}
@@ -315,7 +308,7 @@ func (vh *VerificationHelper) generateAndShowQRCode(ctx context.Context, txn Ver
 		key1 = ownCrossSigningPublicKeys.MasterKey.Bytes()
 
 		// Key 2 is the other device's key.
-		theirDevice, err := vh.mach.GetOrFetchDevice(ctx, txn.TheirUserID, txn.TheirDeviceID)
+		theirDevice, err := vh.mach.GetOrFetchDevice(ctx, txn.TheirUser, txn.TheirDevice)
 		if err != nil {
 			return err
 		}
@@ -333,5 +326,5 @@ func (vh *VerificationHelper) generateAndShowQRCode(ctx context.Context, txn Ver
 	qrCode := NewQRCode(mode, txn.TransactionID, [32]byte(key1), [32]byte(key2))
 	txn.QRCodeSharedSecret = qrCode.SharedSecret
 	vh.showQRCode(ctx, txn.TransactionID, qrCode)
-	return vh.store.SaveVerificationTransaction(ctx, txn)
+	return nil
 }
diff --git a/crypto/verificationhelper/sas.go b/crypto/verificationhelper/sas.go
index 0492dd8d..e28ec405 100644
--- a/crypto/verificationhelper/sas.go
+++ b/crypto/verificationhelper/sas.go
@@ -40,23 +40,23 @@ func (vh *VerificationHelper) StartSAS(ctx context.Context, txnID id.Verificatio
 
 	vh.activeTransactionsLock.Lock()
 	defer vh.activeTransactionsLock.Unlock()
-	txn, err := vh.store.GetVerificationTransaction(ctx, txnID)
-	if err != nil {
-		return fmt.Errorf("failed to get verification transaction %s: %w", txnID, err)
-	} else if txn.VerificationState != VerificationStateReady {
+	txn, ok := vh.activeTransactions[txnID]
+	if !ok {
+		return fmt.Errorf("unknown transaction ID")
+	} else if txn.VerificationState != verificationStateReady {
 		return errors.New("transaction is not in ready state")
 	} else if txn.StartEventContent != nil {
 		return errors.New("start event already sent or received")
 	}
 
-	txn.VerificationState = VerificationStateSASStarted
+	txn.VerificationState = verificationStateSASStarted
 	txn.StartedByUs = true
 	if !slices.Contains(txn.TheirSupportedMethods, event.VerificationMethodSAS) {
 		return fmt.Errorf("the other device does not support SAS verification")
 	}
 
 	// Ensure that we have their device key.
-	_, err = vh.mach.GetOrFetchDevice(ctx, txn.TheirUserID, txn.TheirDeviceID)
+	_, err := vh.mach.GetOrFetchDevice(ctx, txn.TheirUser, txn.TheirDevice)
 	if err != nil {
 		log.Err(err).Msg("Failed to fetch device")
 		return err
@@ -78,9 +78,6 @@ func (vh *VerificationHelper) StartSAS(ctx context.Context, txnID id.Verificatio
 			event.SASMethodEmoji,
 		},
 	}
-	if err := vh.store.SaveVerificationTransaction(ctx, txn); err != nil {
-		return err
-	}
 	return vh.sendVerificationEvent(ctx, txn, event.InRoomVerificationStart, txn.StartEventContent)
 }
 
@@ -97,13 +94,14 @@ func (vh *VerificationHelper) ConfirmSAS(ctx context.Context, txnID id.Verificat
 
 	vh.activeTransactionsLock.Lock()
 	defer vh.activeTransactionsLock.Unlock()
-	txn, err := vh.store.GetVerificationTransaction(ctx, txnID)
-	if err != nil {
-		return fmt.Errorf("failed to get transaction %s: %w", txnID, err)
-	} else if txn.VerificationState != VerificationStateSASKeysExchanged {
+	txn, ok := vh.activeTransactions[txnID]
+	if !ok {
+		return fmt.Errorf("unknown transaction ID")
+	} else if txn.VerificationState != verificationStateSASKeysExchanged {
 		return errors.New("transaction is not in keys exchanged state")
 	}
 
+	var err error
 	keys := map[id.KeyID]jsonbytes.UnpaddedBytes{}
 
 	log.Info().Msg("Signing keys")
@@ -111,7 +109,7 @@ func (vh *VerificationHelper) ConfirmSAS(ctx context.Context, txnID id.Verificat
 	// My device key
 	myDevice := vh.mach.OwnIdentity()
 	myDeviceKeyID := id.NewKeyID(id.KeyAlgorithmEd25519, myDevice.DeviceID.String())
-	keys[myDeviceKeyID], err = vh.verificationMACHKDF(txn, vh.client.UserID, vh.client.DeviceID, txn.TheirUserID, txn.TheirDeviceID, myDeviceKeyID.String(), myDevice.SigningKey.String())
+	keys[myDeviceKeyID], err = vh.verificationMACHKDF(txn, vh.client.UserID, vh.client.DeviceID, txn.TheirUser, txn.TheirDevice, myDeviceKeyID.String(), myDevice.SigningKey.String())
 	if err != nil {
 		return err
 	}
@@ -120,7 +118,7 @@ func (vh *VerificationHelper) ConfirmSAS(ctx context.Context, txnID id.Verificat
 	crossSigningKeys := vh.mach.GetOwnCrossSigningPublicKeys(ctx)
 	if crossSigningKeys != nil {
 		crossSigningKeyID := id.NewKeyID(id.KeyAlgorithmEd25519, crossSigningKeys.MasterKey.String())
-		keys[crossSigningKeyID], err = vh.verificationMACHKDF(txn, vh.client.UserID, vh.client.DeviceID, txn.TheirUserID, txn.TheirDeviceID, crossSigningKeyID.String(), crossSigningKeys.MasterKey.String())
+		keys[crossSigningKeyID], err = vh.verificationMACHKDF(txn, vh.client.UserID, vh.client.DeviceID, txn.TheirUser, txn.TheirDevice, crossSigningKeyID.String(), crossSigningKeys.MasterKey.String())
 		if err != nil {
 			return err
 		}
@@ -131,7 +129,7 @@ func (vh *VerificationHelper) ConfirmSAS(ctx context.Context, txnID id.Verificat
 		keyIDs = append(keyIDs, keyID.String())
 	}
 	slices.Sort(keyIDs)
-	keysMAC, err := vh.verificationMACHKDF(txn, vh.client.UserID, vh.client.DeviceID, txn.TheirUserID, txn.TheirDeviceID, "KEY_IDS", strings.Join(keyIDs, ","))
+	keysMAC, err := vh.verificationMACHKDF(txn, vh.client.UserID, vh.client.DeviceID, txn.TheirUser, txn.TheirDevice, "KEY_IDS", strings.Join(keyIDs, ","))
 	if err != nil {
 		return err
 	}
@@ -147,14 +145,14 @@ func (vh *VerificationHelper) ConfirmSAS(ctx context.Context, txnID id.Verificat
 
 	txn.SentOurMAC = true
 	if txn.ReceivedTheirMAC {
-		txn.VerificationState = VerificationStateSASMACExchanged
+		txn.VerificationState = verificationStateSASMACExchanged
 		err := vh.sendVerificationEvent(ctx, txn, event.InRoomVerificationDone, &event.VerificationDoneEventContent{})
 		if err != nil {
 			return err
 		}
 		txn.SentOurDone = true
 	}
-	return vh.store.SaveVerificationTransaction(ctx, txn)
+	return nil
 }
 
 // onVerificationStartSAS handles the m.key.verification.start events with
@@ -162,7 +160,7 @@ func (vh *VerificationHelper) ConfirmSAS(ctx context.Context, txnID id.Verificat
 // Spec.
 //
 // [Section 11.12.2.2]: https://spec.matrix.org/v1.9/client-server-api/#short-authentication-string-sas-verification
-func (vh *VerificationHelper) onVerificationStartSAS(ctx context.Context, txn VerificationTransaction, evt *event.Event) error {
+func (vh *VerificationHelper) onVerificationStartSAS(ctx context.Context, txn *verificationTransaction, evt *event.Event) error {
 	startEvt := evt.Content.AsVerificationStart()
 	log := vh.getLog(ctx).With().
 		Str("verification_action", "start_sas").
@@ -210,7 +208,7 @@ func (vh *VerificationHelper) onVerificationStartSAS(ctx context.Context, txn Ve
 		return fmt.Errorf("failed to generate ephemeral key: %w", err)
 	}
 	txn.MACMethod = macMethod
-	txn.EphemeralKey = &ECDHPrivateKey{ephemeralKey}
+	txn.EphemeralKey = ephemeralKey
 	txn.StartEventContent = startEvt
 
 	commitment, err := calculateCommitment(ephemeralKey.PublicKey(), startEvt)
@@ -228,8 +226,8 @@ func (vh *VerificationHelper) onVerificationStartSAS(ctx context.Context, txn Ve
 	if err != nil {
 		return fmt.Errorf("failed to send accept event: %w", err)
 	}
-	txn.VerificationState = VerificationStateSASAccepted
-	return vh.store.SaveVerificationTransaction(ctx, txn)
+	txn.VerificationState = verificationStateSASAccepted
+	return nil
 }
 
 func calculateCommitment(ephemeralPubKey *ecdh.PublicKey, startEvt *event.VerificationStartEventContent) ([]byte, error) {
@@ -254,7 +252,7 @@ func calculateCommitment(ephemeralPubKey *ecdh.PublicKey, startEvt *event.Verifi
 // event. This follows Step 4 of [Section 11.12.2.2] of the Spec.
 //
 // [Section 11.12.2.2]: https://spec.matrix.org/v1.9/client-server-api/#short-authentication-string-sas-verification
-func (vh *VerificationHelper) onVerificationAccept(ctx context.Context, txn VerificationTransaction, evt *event.Event) {
+func (vh *VerificationHelper) onVerificationAccept(ctx context.Context, txn *verificationTransaction, evt *event.Event) {
 	acceptEvt := evt.Content.AsVerificationAccept()
 	log := vh.getLog(ctx).With().
 		Str("verification_action", "accept").
@@ -269,7 +267,7 @@ func (vh *VerificationHelper) onVerificationAccept(ctx context.Context, txn Veri
 
 	vh.activeTransactionsLock.Lock()
 	defer vh.activeTransactionsLock.Unlock()
-	if txn.VerificationState != VerificationStateSASStarted {
+	if txn.VerificationState != verificationStateSASStarted {
 		vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUnexpectedMessage,
 			"received accept event for a transaction that is not in the started state")
 		return
@@ -289,18 +287,14 @@ func (vh *VerificationHelper) onVerificationAccept(ctx context.Context, txn Veri
 		return
 	}
 
-	txn.VerificationState = VerificationStateSASAccepted
+	txn.VerificationState = verificationStateSASAccepted
 	txn.MACMethod = acceptEvt.MessageAuthenticationCode
 	txn.Commitment = acceptEvt.Commitment
-	txn.EphemeralKey = &ECDHPrivateKey{ephemeralKey}
+	txn.EphemeralKey = ephemeralKey
 	txn.EphemeralPublicKeyShared = true
-
-	if err := vh.store.SaveVerificationTransaction(ctx, txn); err != nil {
-		log.Err(err).Msg("failed to save verification transaction")
-	}
 }
 
-func (vh *VerificationHelper) onVerificationKey(ctx context.Context, txn VerificationTransaction, evt *event.Event) {
+func (vh *VerificationHelper) onVerificationKey(ctx context.Context, txn *verificationTransaction, evt *event.Event) {
 	log := vh.getLog(ctx).With().
 		Str("verification_action", "key").
 		Logger()
@@ -308,23 +302,22 @@ func (vh *VerificationHelper) onVerificationKey(ctx context.Context, txn Verific
 	vh.activeTransactionsLock.Lock()
 	defer vh.activeTransactionsLock.Unlock()
 
-	if txn.VerificationState != VerificationStateSASAccepted {
+	if txn.VerificationState != verificationStateSASAccepted {
 		vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUnexpectedMessage,
 			"received key event for a transaction that is not in the accepted state")
 		return
 	}
 
 	var err error
-	publicKey, err := ecdh.X25519().NewPublicKey(keyEvt.Key)
+	txn.OtherPublicKey, err = ecdh.X25519().NewPublicKey(keyEvt.Key)
 	if err != nil {
 		log.Err(err).Msg("Failed to generate other public key")
 		return
 	}
-	txn.OtherPublicKey = &ECDHPublicKey{publicKey}
 
 	if txn.EphemeralPublicKeyShared {
 		// Verify that the commitment hash is correct
-		commitment, err := calculateCommitment(publicKey, txn.StartEventContent)
+		commitment, err := calculateCommitment(txn.OtherPublicKey, txn.StartEventContent)
 		if err != nil {
 			log.Err(err).Msg("Failed to calculate commitment")
 			return
@@ -349,7 +342,7 @@ func (vh *VerificationHelper) onVerificationKey(ctx context.Context, txn Verific
 		}
 		txn.EphemeralPublicKeyShared = true
 	}
-	txn.VerificationState = VerificationStateSASKeysExchanged
+	txn.VerificationState = verificationStateSASKeysExchanged
 
 	sasBytes, err := vh.verificationSASHKDF(txn)
 	if err != nil {
@@ -377,14 +370,10 @@ func (vh *VerificationHelper) onVerificationKey(ctx context.Context, txn Verific
 		}
 	}
 	vh.showSAS(ctx, txn.TransactionID, emojis, decimals)
-
-	if err := vh.store.SaveVerificationTransaction(ctx, txn); err != nil {
-		log.Err(err).Msg("failed to save verification transaction")
-	}
 }
 
-func (vh *VerificationHelper) verificationSASHKDF(txn VerificationTransaction) ([]byte, error) {
-	sharedSecret, err := txn.EphemeralKey.ECDH(txn.OtherPublicKey.PublicKey)
+func (vh *VerificationHelper) verificationSASHKDF(txn *verificationTransaction) ([]byte, error) {
+	sharedSecret, err := txn.EphemeralKey.ECDH(txn.OtherPublicKey)
 	if err != nil {
 		return nil, err
 	}
@@ -399,8 +388,8 @@ func (vh *VerificationHelper) verificationSASHKDF(txn VerificationTransaction) (
 	}, "|")
 
 	theirInfo := strings.Join([]string{
-		txn.TheirUserID.String(),
-		txn.TheirDeviceID.String(),
+		txn.TheirUser.String(),
+		txn.TheirDevice.String(),
 		base64.RawStdEncoding.EncodeToString(txn.OtherPublicKey.Bytes()),
 	}, "|")
 
@@ -473,8 +462,8 @@ func BrokenB64Encode(input []byte) string {
 	return string(output)
 }
 
-func (vh *VerificationHelper) verificationMACHKDF(txn VerificationTransaction, senderUser id.UserID, senderDevice id.DeviceID, receivingUser id.UserID, receivingDevice id.DeviceID, keyID, key string) ([]byte, error) {
-	sharedSecret, err := txn.EphemeralKey.ECDH(txn.OtherPublicKey.PublicKey)
+func (vh *VerificationHelper) verificationMACHKDF(txn *verificationTransaction, senderUser id.UserID, senderDevice id.DeviceID, receivingUser id.UserID, receivingDevice id.DeviceID, keyID, key string) ([]byte, error) {
+	sharedSecret, err := txn.EphemeralKey.ECDH(txn.OtherPublicKey)
 	if err != nil {
 		return nil, err
 	}
@@ -574,7 +563,7 @@ var allEmojis = []rune{
 	'📌',
 }
 
-func (vh *VerificationHelper) onVerificationMAC(ctx context.Context, txn VerificationTransaction, evt *event.Event) {
+func (vh *VerificationHelper) onVerificationMAC(ctx context.Context, txn *verificationTransaction, evt *event.Event) {
 	log := vh.getLog(ctx).With().
 		Str("verification_action", "mac").
 		Logger()
@@ -590,12 +579,12 @@ func (vh *VerificationHelper) onVerificationMAC(ctx context.Context, txn Verific
 	for keyID := range macEvt.MAC {
 		keyIDs = append(keyIDs, keyID.String())
 		_, kID := keyID.Parse()
-		if kID == txn.TheirDeviceID.String() {
+		if kID == txn.TheirDevice.String() {
 			hasTheirDeviceKey = true
 		}
 	}
 	slices.Sort(keyIDs)
-	expectedKeyMAC, err := vh.verificationMACHKDF(txn, txn.TheirUserID, txn.TheirDeviceID, vh.client.UserID, vh.client.DeviceID, "KEY_IDS", strings.Join(keyIDs, ","))
+	expectedKeyMAC, err := vh.verificationMACHKDF(txn, txn.TheirUser, txn.TheirDevice, vh.client.UserID, vh.client.DeviceID, "KEY_IDS", strings.Join(keyIDs, ","))
 	if err != nil {
 		vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeSASMismatch, "failed to calculate key list MAC: %w", err)
 		return
@@ -621,8 +610,8 @@ func (vh *VerificationHelper) onVerificationMAC(ctx context.Context, txn Verific
 
 		var key string
 		var theirDevice *id.Device
-		if kID == txn.TheirDeviceID.String() {
-			theirDevice, err = vh.mach.GetOrFetchDevice(ctx, txn.TheirUserID, txn.TheirDeviceID)
+		if kID == txn.TheirDevice.String() {
+			theirDevice, err = vh.mach.GetOrFetchDevice(ctx, txn.TheirUser, txn.TheirDevice)
 			if err != nil {
 				vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUser, "failed to fetch their device: %w", err)
 				return
@@ -641,7 +630,7 @@ func (vh *VerificationHelper) onVerificationMAC(ctx context.Context, txn Verific
 			key = crossSigningKeys.MasterKey.String()
 		}
 
-		expectedMAC, err := vh.verificationMACHKDF(txn, txn.TheirUserID, txn.TheirDeviceID, vh.client.UserID, vh.client.DeviceID, keyID.String(), key)
+		expectedMAC, err := vh.verificationMACHKDF(txn, txn.TheirUser, txn.TheirDevice, vh.client.UserID, vh.client.DeviceID, keyID.String(), key)
 		if err != nil {
 			vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUser, "failed to calculate key MAC: %w", err)
 			return
@@ -652,9 +641,9 @@ func (vh *VerificationHelper) onVerificationMAC(ctx context.Context, txn Verific
 		}
 
 		// Trust their device
-		if kID == txn.TheirDeviceID.String() {
+		if kID == txn.TheirDevice.String() {
 			theirDevice.Trust = id.TrustStateVerified
-			err = vh.mach.CryptoStore.PutDevice(ctx, txn.TheirUserID, theirDevice)
+			err = vh.mach.CryptoStore.PutDevice(ctx, txn.TheirUser, theirDevice)
 			if err != nil {
 				vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUser, "failed to update device trust state after verifying: %w", err)
 				return
@@ -665,7 +654,7 @@ func (vh *VerificationHelper) onVerificationMAC(ctx context.Context, txn Verific
 
 	txn.ReceivedTheirMAC = true
 	if txn.SentOurMAC {
-		txn.VerificationState = VerificationStateSASMACExchanged
+		txn.VerificationState = verificationStateSASMACExchanged
 		err := vh.sendVerificationEvent(ctx, txn, event.InRoomVerificationDone, &event.VerificationDoneEventContent{})
 		if err != nil {
 			vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUser, "failed to send verification done event: %w", err)
@@ -673,8 +662,4 @@ func (vh *VerificationHelper) onVerificationMAC(ctx context.Context, txn Verific
 		}
 		txn.SentOurDone = true
 	}
-
-	if err := vh.store.SaveVerificationTransaction(ctx, txn); err != nil {
-		log.Err(err).Msg("failed to save verification transaction")
-	}
 }
diff --git a/crypto/verificationhelper/verificationhelper.go b/crypto/verificationhelper/verificationhelper.go
index bc424624..be8357f5 100644
--- a/crypto/verificationhelper/verificationhelper.go
+++ b/crypto/verificationhelper/verificationhelper.go
@@ -9,7 +9,7 @@ package verificationhelper
 import (
 	"bytes"
 	"context"
-	"errors"
+	"crypto/ecdh"
 	"fmt"
 	"sync"
 	"time"
@@ -25,6 +25,86 @@ import (
 	"maunium.net/go/mautrix/id"
 )
 
+type verificationState int
+
+const (
+	verificationStateRequested verificationState = iota
+	verificationStateReady
+
+	verificationStateTheirQRScanned // We scanned their QR code
+	verificationStateOurQRScanned   // They scanned our QR code
+
+	verificationStateSASStarted       // An SAS verification has been started
+	verificationStateSASAccepted      // An SAS verification has been accepted
+	verificationStateSASKeysExchanged // An SAS verification has exchanged keys
+	verificationStateSASMACExchanged  // An SAS verification has exchanged MACs
+)
+
+func (step verificationState) String() string {
+	switch step {
+	case verificationStateRequested:
+		return "requested"
+	case verificationStateReady:
+		return "ready"
+	case verificationStateTheirQRScanned:
+		return "their_qr_scanned"
+	case verificationStateOurQRScanned:
+		return "our_qr_scanned"
+	case verificationStateSASStarted:
+		return "sas_started"
+	case verificationStateSASAccepted:
+		return "sas_accepted"
+	case verificationStateSASKeysExchanged:
+		return "sas_keys_exchanged"
+	case verificationStateSASMACExchanged:
+		return "sas_mac"
+	default:
+		return fmt.Sprintf("verificationStep(%d)", step)
+	}
+}
+
+type verificationTransaction struct {
+	// RoomID is the room ID if the verification is happening in a room or
+	// empty if it is a to-device verification.
+	RoomID id.RoomID
+
+	// VerificationState is the current step of the verification flow.
+	VerificationState verificationState
+	// TransactionID is the ID of the verification transaction.
+	TransactionID id.VerificationTransactionID
+
+	// TheirDevice is the device ID of the device that either made the initial
+	// request or accepted our request.
+	TheirDevice id.DeviceID
+	// TheirUser is the user ID of the other user.
+	TheirUser id.UserID
+	// TheirSupportedMethods is a list of verification methods that the other
+	// device supports.
+	TheirSupportedMethods []event.VerificationMethod
+
+	// SentToDeviceIDs is a list of devices which the initial request was sent
+	// to. This is only used for to-device verification requests, and is meant
+	// to be used to send cancellation requests to all other devices when a
+	// verification request is accepted via a m.key.verification.ready event.
+	SentToDeviceIDs []id.DeviceID
+
+	// QRCodeSharedSecret is the shared secret that was encoded in the QR code
+	// that we showed.
+	QRCodeSharedSecret []byte
+
+	StartedByUs              bool                                 // Whether the verification was started by us
+	StartEventContent        *event.VerificationStartEventContent // The m.key.verification.start event content
+	Commitment               []byte                               // The commitment from the m.key.verification.accept event
+	MACMethod                event.MACMethod                      // The method used to calculate the MAC
+	EphemeralKey             *ecdh.PrivateKey                     // The ephemeral key
+	EphemeralPublicKeyShared bool                                 // Whether this device's ephemeral public key has been shared
+	OtherPublicKey           *ecdh.PublicKey                      // The other device's ephemeral public key
+	ReceivedTheirMAC         bool                                 // Whether we have received their MAC
+	SentOurMAC               bool                                 // Whether we have sent our MAC
+	ReceivedTheirDone        bool                                 // Whether we have received their done event
+	SentOurDone              bool                                 // Whether we have sent our done event
+}
+
 // RequiredCallbacks is an interface representing the callbacks required for
 // the [VerificationHelper].
 type RequiredCallbacks interface {
@@ -65,9 +145,8 @@ type VerificationHelper struct {
 	client *mautrix.Client
 	mach   *crypto.OlmMachine
 
-	store                  VerificationStore
+	activeTransactions     map[id.VerificationTransactionID]*verificationTransaction
 	activeTransactionsLock sync.Mutex
-	// activeTransactions     map[id.VerificationTransactionID]*verificationTransaction
 
 	// supportedMethods are the methods that *we* support
 	supportedMethods              []event.VerificationMethod
@@ -84,19 +163,15 @@ type VerificationHelper struct {
 
 var _ mautrix.VerificationHelper = (*VerificationHelper)(nil)
 
-func NewVerificationHelper(client *mautrix.Client, mach *crypto.OlmMachine, store VerificationStore, callbacks any, supportsScan bool) *VerificationHelper {
+func NewVerificationHelper(client *mautrix.Client, mach *crypto.OlmMachine, callbacks any, supportsScan bool) *VerificationHelper {
 	if client.Crypto == nil {
 		panic("client.Crypto is nil")
 	}
 
-	if store == nil {
-		store = NewInMemoryVerificationStore()
-	}
-
 	helper := VerificationHelper{
-		client: client,
-		mach:   mach,
-		store:  store,
+		client:             client,
+		mach:               mach,
+		activeTransactions: map[id.VerificationTransactionID]*verificationTransaction{},
 	}
 
 	if c, ok := callbacks.(RequiredCallbacks); !ok {
@@ -158,7 +233,7 @@ func (vh *VerificationHelper) Init(ctx context.Context) error {
 
 	// Wrapper for the event handlers to check that the transaction ID is known
 	// and ignore the event if it isn't.
-	wrapHandler := func(callback func(context.Context, VerificationTransaction, *event.Event)) func(context.Context, *event.Event) {
+	wrapHandler := func(callback func(context.Context, *verificationTransaction, *event.Event)) func(context.Context, *event.Event) {
 		return func(ctx context.Context, evt *event.Event) {
 			log := vh.getLog(ctx).With().
 				Str("verification_action", "check transaction ID").
@@ -182,11 +257,8 @@ func (vh *VerificationHelper) Init(ctx context.Context) error {
 			log = log.With().Stringer("transaction_id", transactionID).Logger()
 
 			vh.activeTransactionsLock.Lock()
-			txn, err := vh.store.GetVerificationTransaction(ctx, transactionID)
-			if err != nil && errors.Is(err, ErrUnknownVerificationTransaction) {
-				log.Err(err).Msg("failed to get verification transaction")
-				return
-			} else if errors.Is(err, ErrUnknownVerificationTransaction) {
+			txn, ok := vh.activeTransactions[transactionID]
+			if !ok {
 				// If it's a cancellation event for an unknown transaction, we
 				// can just ignore it.
 				if evt.Type == event.ToDeviceVerificationCancel || evt.Type == event.InRoomVerificationCancel {
@@ -199,9 +271,9 @@ func (vh *VerificationHelper) Init(ctx context.Context) error {
 
 				// We have to create a fake transaction so that the call to
 				// cancelVerificationTxn works.
-				txn = VerificationTransaction{
-					RoomID:      evt.RoomID,
-					TheirUserID: evt.Sender,
+				txn = &verificationTransaction{
+					RoomID:    evt.RoomID,
+					TheirUser: evt.Sender,
 				}
 				if transactionable, ok := evt.Content.Parsed.(event.VerificationTransactionable); ok {
 					txn.TransactionID = transactionable.GetTransactionID()
@@ -209,7 +281,7 @@ func (vh *VerificationHelper) Init(ctx context.Context) error {
 					txn.TransactionID = id.VerificationTransactionID(evt.ID)
 				}
 				if fromDevice, ok := evt.Content.Raw["from_device"]; ok {
-					txn.TheirDeviceID = id.DeviceID(fromDevice.(string))
+					txn.TheirDevice = id.DeviceID(fromDevice.(string))
 				}
 
 				// Send a cancellation event.
@@ -250,11 +322,7 @@ func (vh *VerificationHelper) Init(ctx context.Context) error {
 	syncer.OnEventType(event.InRoomVerificationKey, wrapHandler(vh.onVerificationKey))       // SAS
 	syncer.OnEventType(event.InRoomVerificationMAC, wrapHandler(vh.onVerificationMAC))       // SAS
 
-	allTransactions, err := vh.store.GetAllVerificationTransactions(ctx)
-	for _, txn := range allTransactions {
-		vh.expireTransactionAt(txn.TransactionID, txn.ExpirationTime.Time)
-	}
-	return err
+	return nil
 }
 
 // StartVerification starts an interactive verification flow with the given
@@ -314,12 +382,13 @@ func (vh *VerificationHelper) StartVerification(ctx context.Context, to id.UserI
 
 	vh.activeTransactionsLock.Lock()
 	defer vh.activeTransactionsLock.Unlock()
-	return txnID, vh.store.SaveVerificationTransaction(ctx, VerificationTransaction{
-		VerificationState: VerificationStateRequested,
+	vh.activeTransactions[txnID] = &verificationTransaction{
+		VerificationState: verificationStateRequested,
 		TransactionID:     txnID,
-		TheirUserID:       to,
+		TheirUser:         to,
 		SentToDeviceIDs:   maps.Keys(devices),
-	})
+	}
+	return txnID, nil
 }
 
 // StartInRoomVerification starts an interactive verification flow with the
@@ -353,12 +422,13 @@ func (vh *VerificationHelper) StartInRoomVerification(ctx context.Context, roomI
 
 	vh.activeTransactionsLock.Lock()
 	defer vh.activeTransactionsLock.Unlock()
-	return txnID, vh.store.SaveVerificationTransaction(ctx, VerificationTransaction{
+	vh.activeTransactions[txnID] = &verificationTransaction{
 		RoomID:            roomID,
-		VerificationState: VerificationStateRequested,
+		VerificationState: verificationStateRequested,
 		TransactionID:     txnID,
-		TheirUserID:       to,
-	})
+		TheirUser:         to,
+	}
+	return txnID, nil
 }
 
 // AcceptVerification accepts a verification request. The transaction ID should
@@ -370,10 +440,10 @@ func (vh *VerificationHelper) AcceptVerification(ctx context.Context, txnID id.V
 		Stringer("transaction_id", txnID).
 		Logger()
 
-	txn, err := vh.store.GetVerificationTransaction(ctx, txnID)
-	if err != nil {
-		return err
-	} else if txn.VerificationState != VerificationStateRequested {
+	txn, ok := vh.activeTransactions[txnID]
+	if !ok {
+		return fmt.Errorf("unknown transaction ID")
+	} else if txn.VerificationState != verificationStateRequested {
 		return fmt.Errorf("transaction is not in the requested state")
 	}
 
@@ -402,11 +472,11 @@ func (vh *VerificationHelper) AcceptVerification(ctx context.Context, txnID id.V
 		FromDevice: vh.client.DeviceID,
 		Methods:    maps.Keys(supportedMethods),
 	}
-	err = vh.sendVerificationEvent(ctx, txn, event.InRoomVerificationReady, readyEvt)
+	err := vh.sendVerificationEvent(ctx, txn, event.InRoomVerificationReady, readyEvt)
 	if err != nil {
 		return err
 	}
-	txn.VerificationState = VerificationStateReady
+	txn.VerificationState = verificationStateReady
 
 	if vh.scanQRCode != nil && slices.Contains(txn.TheirSupportedMethods, event.VerificationMethodQRCodeShow) {
 		vh.scanQRCode(ctx, txn.TransactionID)
@@ -422,7 +492,8 @@ func (vh *VerificationHelper) AcceptVerification(ctx context.Context, txnID id.V
 func (vh *VerificationHelper) DismissVerification(ctx context.Context, txnID id.VerificationTransactionID) error {
 	vh.activeTransactionsLock.Lock()
 	defer vh.activeTransactionsLock.Unlock()
-	return vh.store.DeleteVerification(ctx, txnID)
+	delete(vh.activeTransactions, txnID)
+	return nil
 }
 
 // DismissVerification cancels the verification request with the given
@@ -433,9 +504,9 @@ func (vh *VerificationHelper) CancelVerification(ctx context.Context, txnID id.V
 	vh.activeTransactionsLock.Lock()
 	defer vh.activeTransactionsLock.Unlock()
 
-	txn, err := vh.store.GetVerificationTransaction(ctx, txnID)
-	if err != nil {
-		return err
+	txn, ok := vh.activeTransactions[txnID]
+	if !ok {
+		return fmt.Errorf("unknown transaction ID")
 	}
 	log := vh.getLog(ctx).With().
 		Str("verification_action", "cancel verification").
@@ -456,28 +527,29 @@ func (vh *VerificationHelper) CancelVerification(ctx context.Context, txnID id.V
 	} else {
 		cancelEvt.SetTransactionID(txn.TransactionID)
 		req := mautrix.ReqSendToDevice{Messages: map[id.UserID]map[id.DeviceID]*event.Content{
-			txn.TheirUserID: {},
+			txn.TheirUser: {},
 		}}
-		if len(txn.TheirDeviceID) > 0 {
+		if len(txn.TheirDevice) > 0 {
 			// Send the cancellation event to only the device that accepted the
 			// verification request. All of the other devices already received a
 			// cancellation event with code "m.acceped".
-			req.Messages[txn.TheirUserID][txn.TheirDeviceID] = &event.Content{Parsed: cancelEvt}
+			req.Messages[txn.TheirUser][txn.TheirDevice] = &event.Content{Parsed: cancelEvt}
 		} else {
 			// Send the cancellation event to all of the devices that we sent the
 			// request to.
 			for _, deviceID := range txn.SentToDeviceIDs {
 				if deviceID != vh.client.DeviceID {
-					req.Messages[txn.TheirUserID][deviceID] = &event.Content{Parsed: cancelEvt}
+					req.Messages[txn.TheirUser][deviceID] = &event.Content{Parsed: cancelEvt}
 				}
 			}
 		}
 		_, err := vh.client.SendToDevice(ctx, event.ToDeviceVerificationCancel, &req)
 		if err != nil {
-			return fmt.Errorf("failed to send m.key.verification.cancel event to %v: %w", maps.Keys(req.Messages[txn.TheirUserID]), err)
+			return fmt.Errorf("failed to send m.key.verification.cancel event to %v: %w", maps.Keys(req.Messages[txn.TheirUser]), err)
 		}
 	}
-	return vh.store.DeleteVerification(ctx, txn.TransactionID)
+	delete(vh.activeTransactions, txn.TransactionID)
+	return nil
 }
 
 // sendVerificationEvent sends a verification event to the other user's device
@@ -489,7 +561,7 @@ func (vh *VerificationHelper) CancelVerification(ctx context.Context, txnID id.V
 //     [event.VerificationTransactionable].
 //   - evtType can be either the to-device or in-room version of the event type
 //     as it is always stringified.
-func (vh *VerificationHelper) sendVerificationEvent(ctx context.Context, txn VerificationTransaction, evtType event.Type, content any) error {
+func (vh *VerificationHelper) sendVerificationEvent(ctx context.Context, txn *verificationTransaction, evtType event.Type, content any) error {
 	if txn.RoomID != "" {
 		content.(event.Relatable).SetRelatesTo(&event.RelatesTo{Type: event.RelReference, EventID: id.EventID(txn.TransactionID)})
 		_, err := vh.client.SendMessageEvent(ctx, txn.RoomID, evtType, &event.Content{
@@ -501,13 +573,13 @@ func (vh *VerificationHelper) sendVerificationEvent(ctx context.Context, txn Ver
 	} else {
 		content.(event.VerificationTransactionable).SetTransactionID(txn.TransactionID)
 		req := mautrix.ReqSendToDevice{Messages: map[id.UserID]map[id.DeviceID]*event.Content{
-			txn.TheirUserID: {
-				txn.TheirDeviceID: &event.Content{Parsed: content},
+			txn.TheirUser: {
+				txn.TheirDevice: &event.Content{Parsed: content},
 			},
 		}}
 		_, err := vh.client.SendToDevice(ctx, evtType, &req)
 		if err != nil {
-			return fmt.Errorf("failed to send %s event to %s: %w", evtType.String(), txn.TheirDeviceID, err)
+			return fmt.Errorf("failed to send %s event to %s: %w", evtType.String(), txn.TheirDevice, err)
 		}
 	}
 	return nil
@@ -519,7 +591,7 @@ func (vh *VerificationHelper) sendVerificationEvent(ctx context.Context, txn Ver
 // directly to expose the error to its caller).
 //
 // Must always be called with the activeTransactionsLock held.
-func (vh *VerificationHelper) cancelVerificationTxn(ctx context.Context, txn VerificationTransaction, code event.VerificationCancelCode, reasonFmtStr string, fmtArgs ...any) error {
+func (vh *VerificationHelper) cancelVerificationTxn(ctx context.Context, txn *verificationTransaction, code event.VerificationCancelCode, reasonFmtStr string, fmtArgs ...any) error {
 	log := vh.getLog(ctx)
 	reason := fmt.Errorf(reasonFmtStr, fmtArgs...).Error()
 	log.Info().
@@ -533,9 +605,7 @@ func (vh *VerificationHelper) cancelVerificationTxn(ctx context.Context, txn Ver
 		log.Err(err).Msg("failed to send cancellation event")
 		return fmt.Errorf("failed to send cancel verification event (code: %s, reason: %s): %w", code, reason, err)
 	}
-	if err = vh.store.DeleteVerification(ctx, txn.TransactionID); err != nil {
-		log.Err(err).Msg("deleting verification failed")
-	}
+	delete(vh.activeTransactions, txn.TransactionID)
 	vh.verificationCancelledCallback(ctx, txn.TransactionID, code, reason)
 	return fmt.Errorf("verification cancelled (code: %s): %s", code, reason)
 }
@@ -614,58 +684,54 @@ func (vh *VerificationHelper) onVerificationRequest(ctx context.Context, evt *ev
 	}
 
 	vh.activeTransactionsLock.Lock()
-	newTxn := VerificationTransaction{
-		ExpirationTime:        jsontime.UnixMilli{Time: verificationRequest.Timestamp.Add(time.Minute * 10)},
+	newTxn := &verificationTransaction{
 		RoomID:                evt.RoomID,
-		VerificationState:     VerificationStateRequested,
+		VerificationState:     verificationStateRequested,
 		TransactionID:         verificationRequest.TransactionID,
-		TheirDeviceID:         verificationRequest.FromDevice,
-		TheirUserID:           evt.Sender,
+		TheirDevice:           verificationRequest.FromDevice,
+		TheirUser:             evt.Sender,
 		TheirSupportedMethods: verificationRequest.Methods,
 	}
-	if txn, err := vh.store.FindVerificationTransactionForUserDevice(ctx, evt.Sender, verificationRequest.FromDevice); err != nil && !errors.Is(err, ErrUnknownVerificationTransaction) {
-		log.Err(err).Stringer("sender", evt.Sender).Stringer("device_id", verificationRequest.FromDevice).Msg("failed to find verification transaction")
-		vh.activeTransactionsLock.Unlock()
-		return
-	} else if !errors.Is(err, ErrUnknownVerificationTransaction) {
-		if txn.TransactionID == verificationRequest.TransactionID {
-			vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUnexpectedMessage, "received a new verification request for the same transaction ID")
-		} else {
-			vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUnexpectedMessage, "received multiple verification requests from the same device")
+	for existingTxnID, existingTxn := range vh.activeTransactions {
+		if existingTxn.TheirUser == evt.Sender && existingTxn.TheirDevice == verificationRequest.FromDevice && existingTxnID != verificationRequest.TransactionID {
+			vh.cancelVerificationTxn(ctx, existingTxn, event.VerificationCancelCodeUnexpectedMessage, "received multiple verification requests from the same device")
 			vh.cancelVerificationTxn(ctx, newTxn, event.VerificationCancelCodeUnexpectedMessage, "received multiple verification requests from the same device")
+			delete(vh.activeTransactions, existingTxnID)
+			vh.activeTransactionsLock.Unlock()
+			return
+		}
+
+		if existingTxnID == verificationRequest.TransactionID {
+			vh.cancelVerificationTxn(ctx, existingTxn, event.VerificationCancelCodeUnexpectedMessage, "received a new verification request for the same transaction ID")
+			delete(vh.activeTransactions, existingTxnID)
+			vh.activeTransactionsLock.Unlock()
+			return
 		}
-		vh.activeTransactionsLock.Unlock()
-		return
-	}
-	if err := vh.store.SaveVerificationTransaction(ctx, newTxn); err != nil {
-		log.Err(err).Msg("failed to save verification transaction")
 	}
+	vh.activeTransactions[verificationRequest.TransactionID] = newTxn
 	vh.activeTransactionsLock.Unlock()
 
 	vh.expireTransactionAt(verificationRequest.TransactionID, verificationRequest.Timestamp.Add(time.Minute*10))
 	vh.verificationRequested(ctx, verificationRequest.TransactionID, evt.Sender)
 }
 
-func (vh *VerificationHelper) expireTransactionAt(txnID id.VerificationTransactionID, expiresAt time.Time) {
+func (vh *VerificationHelper) expireTransactionAt(txnID id.VerificationTransactionID, expireAt time.Time) {
 	go func() {
-		time.Sleep(time.Until(expiresAt))
+		time.Sleep(time.Until(expireAt))
 
 		vh.activeTransactionsLock.Lock()
 		defer vh.activeTransactionsLock.Unlock()
 
-		txn, err := vh.store.GetVerificationTransaction(context.Background(), txnID)
-		if err == ErrUnknownVerificationTransaction {
-			// Already deleted, nothing to expire
+		txn, ok := vh.activeTransactions[txnID]
+		if !ok {
 			return
-		} else if err != nil {
-			vh.getLog(context.Background()).Err(err).Msg("failed to get verification transaction to expire")
-		} else {
-			vh.cancelVerificationTxn(context.Background(), txn, event.VerificationCancelCodeTimeout, "verification timed out")
 		}
+
+		vh.cancelVerificationTxn(context.Background(), txn, event.VerificationCancelCodeTimeout, "verification timed out")
 	}()
 }
 
-func (vh *VerificationHelper) onVerificationReady(ctx context.Context, txn VerificationTransaction, evt *event.Event) {
+func (vh *VerificationHelper) onVerificationReady(ctx context.Context, txn *verificationTransaction, evt *event.Event) {
 	log := vh.getLog(ctx).With().
 		Str("verification_action", "verification ready").
 		Logger()
@@ -673,7 +739,7 @@ func (vh *VerificationHelper) onVerificationReady(ctx context.Context, txn Verif
 	vh.activeTransactionsLock.Lock()
 	defer vh.activeTransactionsLock.Unlock()
 
-	if txn.VerificationState != VerificationStateRequested {
+	if txn.VerificationState != verificationStateRequested {
 		vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUnexpectedMessage, "verification ready event received for a transaction that is not in the requested state")
 		return
 	}
@@ -681,12 +747,12 @@ func (vh *VerificationHelper) onVerificationReady(ctx context.Context, txn Verif
 	readyEvt := evt.Content.AsVerificationReady()
 
 	// Update the transaction state.
-	txn.VerificationState = VerificationStateReady
-	txn.TheirDeviceID = readyEvt.FromDevice
+	txn.VerificationState = verificationStateReady
+	txn.TheirDevice = readyEvt.FromDevice
 	txn.TheirSupportedMethods = readyEvt.Methods
 
 	log.Info().
-		Stringer("their_device_id", txn.TheirDeviceID).
+		Stringer("their_device_id", txn.TheirDevice).
 		Any("their_supported_methods", txn.TheirSupportedMethods).
 		Msg("Received verification ready event")
 
@@ -700,16 +766,16 @@ func (vh *VerificationHelper) onVerificationReady(ctx context.Context, txn Verif
 				Reason:                    "The verification was accepted on another device.",
 			},
 		}
-		req := mautrix.ReqSendToDevice{Messages: map[id.UserID]map[id.DeviceID]*event.Content{txn.TheirUserID: {}}}
+		req := mautrix.ReqSendToDevice{Messages: map[id.UserID]map[id.DeviceID]*event.Content{txn.TheirUser: {}}}
 		for _, deviceID := range txn.SentToDeviceIDs {
-			if deviceID == txn.TheirDeviceID || deviceID == vh.client.DeviceID {
+			if deviceID == txn.TheirDevice || deviceID == vh.client.DeviceID {
 				// Don't ever send a cancellation to the device that accepted
 				// the request or to our own device (which can happen if this
 				// is a self-verification).
 				continue
 			}
 
-			req.Messages[txn.TheirUserID][deviceID] = content
+			req.Messages[txn.TheirUser][deviceID] = content
 		}
 		_, err := vh.client.SendToDevice(ctx, event.ToDeviceVerificationCancel, &req)
 		if err != nil {
@@ -721,17 +787,18 @@ func (vh *VerificationHelper) onVerificationReady(ctx context.Context, txn Verif
 		vh.scanQRCode(ctx, txn.TransactionID)
 	}
 
-	if err := vh.generateAndShowQRCode(ctx, txn); err != nil {
+	err := vh.generateAndShowQRCode(ctx, txn)
+	if err != nil {
 		vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUser, "failed to generate and show QR code: %w", err)
 	}
 }
 
-func (vh *VerificationHelper) onVerificationStart(ctx context.Context, txn VerificationTransaction, evt *event.Event) {
+func (vh *VerificationHelper) onVerificationStart(ctx context.Context, txn *verificationTransaction, evt *event.Event) {
 	startEvt := evt.Content.AsVerificationStart()
 	log := vh.getLog(ctx).With().
 		Str("verification_action", "verification start").
 		Str("method", string(startEvt.Method)).
-		Stringer("their_device_id", txn.TheirDeviceID).
+		Stringer("their_device_id", txn.TheirDevice).
 		Any("their_supported_methods", txn.TheirSupportedMethods).
 		Bool("started_by_us", txn.StartedByUs).
 		Logger()
@@ -741,7 +808,7 @@ func (vh *VerificationHelper) onVerificationStart(ctx context.Context, txn Verif
 	vh.activeTransactionsLock.Lock()
 	defer vh.activeTransactionsLock.Unlock()
 
-	if txn.VerificationState == VerificationStateSASStarted || txn.VerificationState == VerificationStateOurQRScanned || txn.VerificationState == VerificationStateTheirQRScanned {
+	if txn.VerificationState == verificationStateSASStarted || txn.VerificationState == verificationStateOurQRScanned || txn.VerificationState == verificationStateTheirQRScanned {
 		// We might have sent the event, and they also sent an event.
 		if txn.StartEventContent == nil || !txn.StartedByUs {
 			// We didn't sent a start event yet, so we have gotten ourselves
@@ -773,12 +840,12 @@ func (vh *VerificationHelper) onVerificationStart(ctx context.Context, txn Verif
 			return
 		}
 
-		if txn.TheirUserID < vh.client.UserID || (txn.TheirUserID == vh.client.UserID && txn.TheirDeviceID < vh.client.DeviceID) {
+		if txn.TheirUser < vh.client.UserID || (txn.TheirUser == vh.client.UserID && txn.TheirDevice < vh.client.DeviceID) {
 			log.Debug().Msg("Using their start event instead of ours because they are alphabetically before us")
 			txn.StartedByUs = false
 			txn.StartEventContent = startEvt
 		}
-	} else if txn.VerificationState != VerificationStateReady {
+	} else if txn.VerificationState != verificationStateReady {
 		vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUnexpectedMessage, "got start event for transaction that is not in ready state")
 		return
 	}
@@ -786,7 +853,7 @@ func (vh *VerificationHelper) onVerificationStart(ctx context.Context, txn Verif
 	switch startEvt.Method {
 	case event.VerificationMethodSAS:
 		log.Info().Msg("Received SAS start event")
-		txn.VerificationState = VerificationStateSASStarted
+		txn.VerificationState = verificationStateSASStarted
 		if err := vh.onVerificationStartSAS(ctx, txn, evt); err != nil {
 			vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUser, "failed to handle SAS verification start: %w", err)
 		}
@@ -796,11 +863,8 @@ func (vh *VerificationHelper) onVerificationStart(ctx context.Context, txn Verif
 			vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeKeyMismatch, "reciprocated shared secret does not match")
 			return
 		}
-		txn.VerificationState = VerificationStateOurQRScanned
+		txn.VerificationState = verificationStateOurQRScanned
 		vh.qrCodeScaned(ctx, txn.TransactionID)
-		if err := vh.store.SaveVerificationTransaction(ctx, txn); err != nil {
-			log.Err(err).Msg("failed to save verification transaction")
-		}
 	default:
 		// Note that we should never get m.qr_code.show.v1 or m.qr_code.scan.v1
 		// here, since the start command for scanning and showing QR codes
@@ -810,18 +874,17 @@ func (vh *VerificationHelper) onVerificationStart(ctx context.Context, txn Verif
 	}
 }
 
-func (vh *VerificationHelper) onVerificationDone(ctx context.Context, txn VerificationTransaction, evt *event.Event) {
-	log := vh.getLog(ctx).With().
+func (vh *VerificationHelper) onVerificationDone(ctx context.Context, txn *verificationTransaction, evt *event.Event) {
+	vh.getLog(ctx).Info().
 		Str("verification_action", "done").
 		Stringer("transaction_id", txn.TransactionID).
 		Bool("sent_our_done", txn.SentOurDone).
-		Logger()
-	log.Info().Msg("Verification done")
+		Msg("Verification done")
 	vh.activeTransactionsLock.Lock()
 	defer vh.activeTransactionsLock.Unlock()
 
-	if !slices.Contains([]VerificationState{
-		VerificationStateTheirQRScanned, VerificationStateOurQRScanned, VerificationStateSASMACExchanged,
+	if !slices.Contains([]verificationState{
+		verificationStateTheirQRScanned, verificationStateOurQRScanned, verificationStateSASMACExchanged,
 	}, txn.VerificationState) {
 		vh.cancelVerificationTxn(ctx, txn, event.VerificationCancelCodeUnexpectedMessage, "got done event for transaction that is not in QR-scanned or MAC-exchanged state")
 		return
@@ -829,16 +892,12 @@ func (vh *VerificationHelper) onVerificationDone(ctx context.Context, txn Verifi
 
 	txn.ReceivedTheirDone = true
 	if txn.SentOurDone {
-		if err := vh.store.DeleteVerification(ctx, txn.TransactionID); err != nil {
-			log.Err(err).Msg("Delete verification failed")
-		}
+		delete(vh.activeTransactions, txn.TransactionID)
 		vh.verificationDone(ctx, txn.TransactionID)
-	} else if err := vh.store.SaveVerificationTransaction(ctx, txn); err != nil {
-		log.Err(err).Msg("failed to save verification transaction")
 	}
 }
 
-func (vh *VerificationHelper) onVerificationCancel(ctx context.Context, txn VerificationTransaction, evt *event.Event) {
+func (vh *VerificationHelper) onVerificationCancel(ctx context.Context, txn *verificationTransaction, evt *event.Event) {
 	cancelEvt := evt.Content.AsVerificationCancel()
 	log := vh.getLog(ctx).With().
 		Str("verification_action", "cancel").
@@ -864,7 +923,7 @@ func (vh *VerificationHelper) onVerificationCancel(ctx context.Context, txn Veri
 	// that is currently in the REQUESTED state, then we will send
 	// cancellations to all of the devices that we sent the request to. This
 	// will ensure that all of the clients know that the request was cancelled.
-	if txn.VerificationState == VerificationStateRequested && len(txn.SentToDeviceIDs) > 0 {
+	if txn.VerificationState == verificationStateRequested && len(txn.SentToDeviceIDs) > 0 {
 		content := &event.Content{
 			Parsed: &event.VerificationCancelEventContent{
 				ToDeviceVerificationEvent: event.ToDeviceVerificationEvent{TransactionID: txn.TransactionID},
@@ -872,9 +931,9 @@ func (vh *VerificationHelper) onVerificationCancel(ctx context.Context, txn Veri
 				Reason:                    "The verification was rejected from another device.",
 			},
 		}
-		req := mautrix.ReqSendToDevice{Messages: map[id.UserID]map[id.DeviceID]*event.Content{txn.TheirUserID: {}}}
+		req := mautrix.ReqSendToDevice{Messages: map[id.UserID]map[id.DeviceID]*event.Content{txn.TheirUser: {}}}
 		for _, deviceID := range txn.SentToDeviceIDs {
-			req.Messages[txn.TheirUserID][deviceID] = content
+			req.Messages[txn.TheirUser][deviceID] = content
 		}
 		_, err := vh.client.SendToDevice(ctx, event.ToDeviceVerificationCancel, &req)
 		if err != nil {
@@ -882,8 +941,6 @@ func (vh *VerificationHelper) onVerificationCancel(ctx context.Context, txn Veri
 		}
 	}
 
-	if err := vh.store.DeleteVerification(ctx, txn.TransactionID); err != nil {
-		log.Err(err).Msg("Delete verification failed")
-	}
+	delete(vh.activeTransactions, txn.TransactionID)
 	vh.verificationCancelledCallback(ctx, txn.TransactionID, cancelEvt.Code, cancelEvt.Reason)
 }
diff --git a/crypto/verificationhelper/verificationhelper_qr_self_test.go b/crypto/verificationhelper/verificationhelper_qr_self_test.go
index 937cc414..11358b88 100644
--- a/crypto/verificationhelper/verificationhelper_qr_self_test.go
+++ b/crypto/verificationhelper/verificationhelper_qr_self_test.go
@@ -278,12 +278,12 @@ func TestSelfVerification_ScanQRTransactionIDCorrupted(t *testing.T) {
 	// Emulate scanning the QR code shown by the receiving device
 	// on the sending device.
 	err = sendingHelper.HandleScannedQRData(ctx, receivingShownQRCodeBytes)
-	assert.ErrorContains(t, err, "unknown transaction ID")
+	assert.ErrorContains(t, err, "unknown transaction ID found in QR code")
 
 	// Emulate scanning the QR code shown by the sending device on
 	// the receiving device.
 	err = receivingHelper.HandleScannedQRData(ctx, sendingShownQRCodeBytes)
-	assert.ErrorContains(t, err, "unknown transaction ID")
+	assert.ErrorContains(t, err, "unknown transaction ID found in QR code")
 }
 
 func TestSelfVerification_ScanQRKeyCorrupted(t *testing.T) {
diff --git a/crypto/verificationhelper/verificationhelper_test.go b/crypto/verificationhelper/verificationhelper_test.go
index d0bf2298..273042c3 100644
--- a/crypto/verificationhelper/verificationhelper_test.go
+++ b/crypto/verificationhelper/verificationhelper_test.go
@@ -65,11 +65,11 @@ func initServerAndLoginAliceBob(t *testing.T, ctx context.Context) (ts *mockServ
 func initDefaultCallbacks(t *testing.T, ctx context.Context, sendingClient, receivingClient *mautrix.Client, sendingMachine, receivingMachine *crypto.OlmMachine) (sendingCallbacks, receivingCallbacks *allVerificationCallbacks, sendingHelper, receivingHelper *verificationhelper.VerificationHelper) {
 	t.Helper()
 	sendingCallbacks = newAllVerificationCallbacks()
-	sendingHelper = verificationhelper.NewVerificationHelper(sendingClient, sendingMachine, nil, sendingCallbacks, true)
+	sendingHelper = verificationhelper.NewVerificationHelper(sendingClient, sendingMachine, sendingCallbacks, true)
 	require.NoError(t, sendingHelper.Init(ctx))
 
 	receivingCallbacks = newAllVerificationCallbacks()
-	receivingHelper = verificationhelper.NewVerificationHelper(receivingClient, receivingMachine, nil, receivingCallbacks, true)
+	receivingHelper = verificationhelper.NewVerificationHelper(receivingClient, receivingMachine, receivingCallbacks, true)
 	require.NoError(t, receivingHelper.Init(ctx))
 	return
 }
@@ -104,7 +104,7 @@ func TestVerification_Start(t *testing.T) {
 			addDeviceID(ctx, cryptoStore, aliceUserID, receivingDeviceID)
 			addDeviceID(ctx, cryptoStore, aliceUserID, receivingDeviceID2)
 
-			senderHelper := verificationhelper.NewVerificationHelper(client, client.Crypto.(*cryptohelper.CryptoHelper).Machine(), nil, tc.callbacks, tc.supportsScan)
+			senderHelper := verificationhelper.NewVerificationHelper(client, client.Crypto.(*cryptohelper.CryptoHelper).Machine(), tc.callbacks, tc.supportsScan)
 			err := senderHelper.Init(ctx)
 			require.NoError(t, err)
 
@@ -151,7 +151,7 @@ func TestVerification_StartThenCancel(t *testing.T) {
 
 			bystanderClient, _ := ts.Login(t, ctx, aliceUserID, bystanderDeviceID)
 			bystanderMachine := bystanderClient.Crypto.(*cryptohelper.CryptoHelper).Machine()
-			bystanderHelper := verificationhelper.NewVerificationHelper(bystanderClient, bystanderMachine, nil, newAllVerificationCallbacks(), true)
+			bystanderHelper := verificationhelper.NewVerificationHelper(bystanderClient, bystanderMachine, newAllVerificationCallbacks(), true)
 			require.NoError(t, bystanderHelper.Init(ctx))
 
 			require.NoError(t, sendingCryptoStore.PutDevice(ctx, aliceUserID, bystanderMachine.OwnIdentity()))
@@ -241,12 +241,12 @@ func TestVerification_Accept_NoSupportedMethods(t *testing.T) {
 	assert.NotEmpty(t, recoveryKey)
 	assert.NotNil(t, cache)
 
-	sendingHelper := verificationhelper.NewVerificationHelper(sendingClient, sendingMachine, nil, newAllVerificationCallbacks(), true)
+	sendingHelper := verificationhelper.NewVerificationHelper(sendingClient, sendingMachine, newAllVerificationCallbacks(), true)
 	err = sendingHelper.Init(ctx)
 	require.NoError(t, err)
 
 	receivingCallbacks := newBaseVerificationCallbacks()
-	receivingHelper := verificationhelper.NewVerificationHelper(receivingClient, receivingClient.Crypto.(*cryptohelper.CryptoHelper).Machine(), nil, receivingCallbacks, false)
+	receivingHelper := verificationhelper.NewVerificationHelper(receivingClient, receivingClient.Crypto.(*cryptohelper.CryptoHelper).Machine(), receivingCallbacks, false)
 	err = receivingHelper.Init(ctx)
 	require.NoError(t, err)
 
@@ -289,11 +289,11 @@ func TestVerification_Accept_CorrectMethodsPresented(t *testing.T) {
 			assert.NotEmpty(t, recoveryKey)
 			assert.NotNil(t, sendingCrossSigningKeysCache)
 
-			sendingHelper := verificationhelper.NewVerificationHelper(sendingClient, sendingMachine, nil, tc.sendingCallbacks, tc.sendingSupportsScan)
+			sendingHelper := verificationhelper.NewVerificationHelper(sendingClient, sendingMachine, tc.sendingCallbacks, tc.sendingSupportsScan)
 			err = sendingHelper.Init(ctx)
 			require.NoError(t, err)
 
-			receivingHelper := verificationhelper.NewVerificationHelper(receivingClient, receivingMachine, nil, tc.receivingCallbacks, tc.receivingSupportsScan)
+			receivingHelper := verificationhelper.NewVerificationHelper(receivingClient, receivingMachine, tc.receivingCallbacks, tc.receivingSupportsScan)
 			err = receivingHelper.Init(ctx)
 			require.NoError(t, err)
 
diff --git a/crypto/verificationhelper/verificationstore.go b/crypto/verificationhelper/verificationstore.go
deleted file mode 100644
index 725a66a6..00000000
--- a/crypto/verificationhelper/verificationstore.go
+++ /dev/null
@@ -1,187 +0,0 @@
-package verificationhelper
-
-import (
-	"context"
-	"crypto/ecdh"
-	"encoding/json"
-	"errors"
-	"fmt"
-
-	"go.mau.fi/util/jsontime"
-
-	"maunium.net/go/mautrix/event"
-	"maunium.net/go/mautrix/id"
-)
-
-var ErrUnknownVerificationTransaction = errors.New("unknown transaction ID")
-
-type VerificationState int
-
-const (
-	VerificationStateRequested VerificationState = iota
-	VerificationStateReady
-
-	VerificationStateTheirQRScanned // We scanned their QR code
-	VerificationStateOurQRScanned   // They scanned our QR code
-
-	VerificationStateSASStarted       // An SAS verification has been started
-	VerificationStateSASAccepted      // An SAS verification has been accepted
-	VerificationStateSASKeysExchanged // An SAS verification has exchanged keys
-	VerificationStateSASMACExchanged  // An SAS verification has exchanged MACs
-)
-
-func (step VerificationState) String() string {
-	switch step {
-	case VerificationStateRequested:
-		return "requested"
-	case VerificationStateReady:
-		return "ready"
-	case VerificationStateTheirQRScanned:
-		return "their_qr_scanned"
-	case VerificationStateOurQRScanned:
-		return "our_qr_scanned"
-	case VerificationStateSASStarted:
-		return "sas_started"
-	case VerificationStateSASAccepted:
-		return "sas_accepted"
-	case VerificationStateSASKeysExchanged:
-		return "sas_keys_exchanged"
-	case VerificationStateSASMACExchanged:
-		return "sas_mac"
-	default:
-		return fmt.Sprintf("VerificationState(%d)", step)
-	}
-}
-
-type ECDHPrivateKey struct {
-	*ecdh.PrivateKey
-}
-
-func (e *ECDHPrivateKey) UnmarshalJSON(data []byte) (err error) {
-	e.PrivateKey, err = ecdh.P256().NewPrivateKey(data)
-	return
-}
-
-func (e *ECDHPrivateKey) MarshalJSON() ([]byte, error) {
-	return json.Marshal(e.Bytes())
-}
-
-type ECDHPublicKey struct {
-	*ecdh.PublicKey
-}
-
-func (e *ECDHPublicKey) UnmarshalJSON(data []byte) (err error) {
-	e.PublicKey, err = ecdh.P256().NewPublicKey(data)
-	return
-}
-
-func (e *ECDHPublicKey) MarshalJSON() ([]byte, error) {
-	return json.Marshal(e.Bytes())
-}
-
-type VerificationTransaction struct {
-	ExpirationTime jsontime.UnixMilli `json:"expiration_time"`
-
-	// RoomID is the room ID if the verification is happening in a room or
-	// empty if it is a to-device verification.
-	RoomID id.RoomID `json:"room_id"`
-
-	// VerificationState is the current step of the verification flow.
-	VerificationState VerificationState `json:"verification_state"`
-	// TransactionID is the ID of the verification transaction.
-	TransactionID id.VerificationTransactionID `json:"transaction_id"`
-
-	// TheirDeviceID is the device ID of the device that either made the
-	// initial request or accepted our request.
-	TheirDeviceID id.DeviceID `json:"their_device_id"`
-	// TheirUserID is the user ID of the other user.
-	TheirUserID id.UserID `json:"their_user_id"`
-	// TheirSupportedMethods is a list of verification methods that the other
-	// device supports.
-	TheirSupportedMethods []event.VerificationMethod `json:"their_supported_methods"`
-
-	// SentToDeviceIDs is a list of devices which the initial request was sent
-	// to. This is only used for to-device verification requests, and is meant
-	// to be used to send cancellation requests to all other devices when a
-	// verification request is accepted via a m.key.verification.ready event.
-	SentToDeviceIDs []id.DeviceID `json:"sent_to_device_ids"`
-
-	// QRCodeSharedSecret is the shared secret that was encoded in the QR code
-	// that we showed.
-	QRCodeSharedSecret []byte `json:"qr_code_shared_secret"`
-
-	StartedByUs              bool                                 `json:"started_by_us"`               // Whether the verification was started by us
-	StartEventContent        *event.VerificationStartEventContent `json:"start_event_content"`         // The m.key.verification.start event content
-	Commitment               []byte                               `json:"committment"`                 // The commitment from the m.key.verification.accept event
-	MACMethod                event.MACMethod                      `json:"mac_method"`                  // The method used to calculate the MAC
-	EphemeralKey             *ECDHPrivateKey                      `json:"ephemeral_key"`               // The ephemeral key
-	EphemeralPublicKeyShared bool                                 `json:"ephemeral_public_key_shared"` // Whether this device's ephemeral public key has been shared
-	OtherPublicKey           *ECDHPublicKey                       `json:"other_public_key"`            // The other device's ephemeral public key
-	ReceivedTheirMAC         bool                                 `json:"received_their_mac"`          // Whether we have received their MAC
-	SentOurMAC               bool                                 `json:"sent_our_mac"`                // Whether we have sent our MAC
-	ReceivedTheirDone        bool                                 `json:"received_their_done"`         // Whether we have received their done event
-	SentOurDone              bool                                 `json:"sent_our_done"`               // Whether we have sent our done event
-}
-
-type VerificationStore interface {
-	// DeleteVerification deletes a verification transaction by ID
-	DeleteVerification(ctx context.Context, txnID id.VerificationTransactionID) error
-	// GetVerificationTransaction gets a verification transaction by ID
-	GetVerificationTransaction(ctx context.Context, txnID id.VerificationTransactionID) (VerificationTransaction, error)
-	// SaveVerificationTransaction saves a verification transaction by ID
-	SaveVerificationTransaction(ctx context.Context, txn VerificationTransaction) error
-	// FindVerificationTransactionForUserDevice finds a verification
-	// transaction by user and device ID
-	FindVerificationTransactionForUserDevice(ctx context.Context, userID id.UserID, deviceID id.DeviceID) (VerificationTransaction, error)
-	// GetAllVerificationTransactions returns all of the verification
-	// transactions. This is used to reset the cancellation timeouts.
-	GetAllVerificationTransactions(ctx context.Context) ([]VerificationTransaction, error)
-}
-
-type InMemoryVerificationStore struct {
-	txns map[id.VerificationTransactionID]VerificationTransaction
-}
-
-var _ VerificationStore = (*InMemoryVerificationStore)(nil)
-
-func NewInMemoryVerificationStore() *InMemoryVerificationStore {
-	return &InMemoryVerificationStore{
-		txns: map[id.VerificationTransactionID]VerificationTransaction{},
-	}
-}
-
-func (i *InMemoryVerificationStore) DeleteVerification(ctx context.Context, txnID id.VerificationTransactionID) error {
-	if _, ok := i.txns[txnID]; !ok {
-		return ErrUnknownVerificationTransaction
-	}
-	delete(i.txns, txnID)
-	return nil
-}
-
-func (i *InMemoryVerificationStore) GetVerificationTransaction(ctx context.Context, txnID id.VerificationTransactionID) (VerificationTransaction, error) {
-	if _, ok := i.txns[txnID]; !ok {
-		return VerificationTransaction{}, ErrUnknownVerificationTransaction
-	}
-	return i.txns[txnID], nil
-}
-
-func (i *InMemoryVerificationStore) SaveVerificationTransaction(ctx context.Context, txn VerificationTransaction) error {
-	i.txns[txn.TransactionID] = txn
-	return nil
-}
-
-func (i *InMemoryVerificationStore) FindVerificationTransactionForUserDevice(ctx context.Context, userID id.UserID, deviceID id.DeviceID) (VerificationTransaction, error) {
-	for _, existingTxn := range i.txns {
-		if existingTxn.TheirUserID == userID && existingTxn.TheirDeviceID == deviceID {
-			return existingTxn, nil
-		}
-	}
-	return VerificationTransaction{}, ErrUnknownVerificationTransaction
-}
-
-func (i *InMemoryVerificationStore) GetAllVerificationTransactions(ctx context.Context) (txns []VerificationTransaction, err error) {
-	for _, txn := range i.txns {
-		txns = append(txns, txn)
-	}
-	return
-}