diff --git a/keyserver/src/responders/website-responders.js b/keyserver/src/responders/website-responders.js
--- a/keyserver/src/responders/website-responders.js
+++ b/keyserver/src/responders/website-responders.js
@@ -28,6 +28,7 @@
 import { defaultWebEnabledApps } from 'lib/types/enabled-apps.js';
 import { entryStoreValidator } from 'lib/types/entry-types.js';
 import { defaultCalendarFilters } from 'lib/types/filter-types.js';
+import { keyserverStoreValidator } from 'lib/types/keyserver-types.js';
 import { inviteLinksStoreValidator } from 'lib/types/link-types.js';
 import {
   defaultNumberPerThread,
@@ -253,6 +254,7 @@
     'default lastCommunicatedPlatformDetails',
     _isEqual({}),
   ),
+  keyserverStore: keyserverStoreValidator,
 });
 
 async function websiteResponder(
@@ -600,6 +602,7 @@
     commServicesAccessToken: null,
     inviteLinksStore: inviteLinksStorePromise,
     lastCommunicatedPlatformDetails: {},
+    keyserverStore: { keyserverInfos: {} },
   });
   const validatedInitialReduxState = validateOutput(
     viewer.platformDetails,
diff --git a/lib/reducers/keyserver-reducer.js b/lib/reducers/keyserver-reducer.js
new file mode 100644
--- /dev/null
+++ b/lib/reducers/keyserver-reducer.js
@@ -0,0 +1,49 @@
+// @flow
+
+import { resetUserStateActionType } from '../actions/user-actions.js';
+import type { KeyserverStore } from '../types/keyserver-types';
+import type { BaseAction } from '../types/redux-types.js';
+import { setNewSessionActionType } from '../utils/action-utils.js';
+import { ashoatKeyserverID } from '../utils/validation-utils.js';
+
+export default function reduceKeyserverStore(
+  state: KeyserverStore,
+  action: BaseAction,
+): KeyserverStore {
+  // this action is only dispatched on native
+  if (action.type === resetUserStateActionType) {
+    const stateCookie = state.keyserverInfos[ashoatKeyserverID]?.cookie;
+    const cookie =
+      stateCookie && stateCookie.startsWith('anonymous=') ? stateCookie : null;
+
+    const keyserverInfos = { ...state.keyserverInfos };
+    for (const key in keyserverInfos) {
+      keyserverInfos[key] = { ...keyserverInfos[key], cookie: null };
+    }
+
+    return {
+      ...state,
+      keyserverInfos: {
+        ...keyserverInfos,
+        [ashoatKeyserverID]: {
+          ...state.keyserverInfos[ashoatKeyserverID],
+          cookie,
+        },
+      },
+    };
+  } else if (action.type === setNewSessionActionType) {
+    if (action.payload.sessionChange.cookie !== undefined) {
+      return {
+        ...state,
+        keyserverInfos: {
+          ...state.keyserverInfos,
+          [ashoatKeyserverID]: {
+            ...state.keyserverInfos[ashoatKeyserverID],
+            cookie: action.payload.sessionChange.cookie,
+          },
+        },
+      };
+    }
+  }
+  return state;
+}
diff --git a/lib/reducers/master-reducer.js b/lib/reducers/master-reducer.js
--- a/lib/reducers/master-reducer.js
+++ b/lib/reducers/master-reducer.js
@@ -8,6 +8,7 @@
 import reduceEnabledApps from './enabled-apps-reducer.js';
 import { reduceEntryInfos } from './entry-reducer.js';
 import reduceInviteLinks from './invite-links-reducer.js';
+import reduceKeyserverStore from './keyserver-reducer.js';
 import reduceLastCommunicatedPlatformDetails from './last-communicated-platform-details-reducer.js';
 import reduceLifecycleState from './lifecycle-state-reducer.js';
 import { reduceLoadingStatuses } from './loading-reducer.js';
@@ -133,6 +134,7 @@
         action,
         state.urlPrefix,
       ),
+      keyserverStore: reduceKeyserverStore(state.keyserverStore, action),
     },
     storeOperations: {
       draftStoreOperations,
diff --git a/lib/types/keyserver-types.js b/lib/types/keyserver-types.js
new file mode 100644
--- /dev/null
+++ b/lib/types/keyserver-types.js
@@ -0,0 +1,26 @@
+// @flow
+
+import t, { type TInterface } from 'tcomb';
+
+import { tShape } from '../utils/validation-utils.js';
+
+// Once we start using the cookie field on web,
+// the cookie field type should be changed to string | null.
+// See https://linear.app/comm/issue/ENG-4347/stop-using-browser-cookies
+export type KeyserverInfo = {
+  +cookie?: ?string,
+};
+
+export type KeyserverStore = {
+  +keyserverInfos: { +[key: string]: KeyserverInfo },
+};
+
+export const keyserverInfoValidator: TInterface<KeyserverInfo> =
+  tShape<KeyserverInfo>({
+    cookie: t.maybe(t.String),
+  });
+
+export const keyserverStoreValidator: TInterface<KeyserverStore> =
+  tShape<KeyserverStore>({
+    keyserverInfos: t.dict(t.String, keyserverInfoValidator),
+  });
diff --git a/lib/types/redux-types.js b/lib/types/redux-types.js
--- a/lib/types/redux-types.js
+++ b/lib/types/redux-types.js
@@ -39,6 +39,7 @@
   CalendarThreadFilter,
   SetCalendarDeletedFilterPayload,
 } from './filter-types.js';
+import type { KeyserverStore } from './keyserver-types.js';
 import type { LifecycleState } from './lifecycle-state-types.js';
 import type {
   FetchInviteLinksResponse,
@@ -138,6 +139,7 @@
   +commServicesAccessToken: ?string,
   +inviteLinksStore: InviteLinksStore,
   +lastCommunicatedPlatformDetails: LastCommunicatedPlatformDetails,
+  +keyserverStore: KeyserverStore,
   ...
 };
 
diff --git a/lib/utils/sanitization.js b/lib/utils/sanitization.js
--- a/lib/utils/sanitization.js
+++ b/lib/utils/sanitization.js
@@ -301,7 +301,12 @@
 ): AppState {
   if (state.cookie !== undefined && state.cookie !== null) {
     const oldState: NativeAppState = state;
-    state = { ...oldState, cookie: null };
+    const keyserverInfos = { ...oldState.keyserverStore.keyserverInfos };
+    for (const key in keyserverInfos) {
+      keyserverInfos[key] = { ...keyserverInfos[key], cookie: null };
+    }
+    const keyserverStore = { ...oldState.keyserverStore, keyserverInfos };
+    state = { ...oldState, cookie: null, keyserverStore };
   }
   if (state.deviceToken !== undefined && state.deviceToken !== null) {
     const oldState: AppState = state;
diff --git a/native/redux/redux-setup.js b/native/redux/redux-setup.js
--- a/native/redux/redux-setup.js
+++ b/native/redux/redux-setup.js
@@ -123,6 +123,7 @@
     links: {},
   },
   lastCommunicatedPlatformDetails: {},
+  keyserverStore: { keyserverInfos: {} },
 }: AppState);
 
 function reducer(state: AppState = defaultState, action: Action) {
diff --git a/native/redux/state-types.js b/native/redux/state-types.js
--- a/native/redux/state-types.js
+++ b/native/redux/state-types.js
@@ -8,6 +8,7 @@
 import type { EnabledApps } from 'lib/types/enabled-apps.js';
 import type { EntryStore } from 'lib/types/entry-types.js';
 import type { CalendarFilter } from 'lib/types/filter-types.js';
+import type { KeyserverStore } from 'lib/types/keyserver-types.js';
 import type { LifecycleState } from 'lib/types/lifecycle-state-types.js';
 import type { InviteLinksStore } from 'lib/types/link-types.js';
 import type { LoadingStatus } from 'lib/types/loading-types.js';
@@ -61,4 +62,5 @@
   +commServicesAccessToken: ?string,
   +inviteLinksStore: InviteLinksStore,
   +lastCommunicatedPlatformDetails: LastCommunicatedPlatformDetails,
+  +keyserverStore: KeyserverStore,
 };
diff --git a/native/redux/unshim-utils.js b/native/redux/unshim-utils.js
--- a/native/redux/unshim-utils.js
+++ b/native/redux/unshim-utils.js
@@ -54,7 +54,16 @@
     commCoreModule.processMessageStoreOperationsSync(operations);
   } catch (exception) {
     console.log(exception);
-    return { ...state, cookie: null };
+    const keyserverInfos = { ...state.keyserverStore.keyserverInfos };
+    for (const key in keyserverInfos) {
+      keyserverInfos[key] = { ...keyserverInfos[key], cookie: null };
+    }
+    const keyserverStore = { ...state.keyserverStore, keyserverInfos };
+    return {
+      ...state,
+      cookie: null,
+      keyserverStore,
+    };
   }
 
   return state;
diff --git a/web/redux/redux-setup.js b/web/redux/redux-setup.js
--- a/web/redux/redux-setup.js
+++ b/web/redux/redux-setup.js
@@ -23,6 +23,7 @@
 import type { EnabledApps } from 'lib/types/enabled-apps.js';
 import type { EntryStore } from 'lib/types/entry-types.js';
 import { type CalendarFilter } from 'lib/types/filter-types.js';
+import type { KeyserverStore } from 'lib/types/keyserver-types.js';
 import type { LifecycleState } from 'lib/types/lifecycle-state-types.js';
 import type { InviteLinksStore } from 'lib/types/link-types.js';
 import type { LoadingStatus } from 'lib/types/loading-types.js';
@@ -100,6 +101,7 @@
   +commServicesAccessToken: ?string,
   +inviteLinksStore: InviteLinksStore,
   +lastCommunicatedPlatformDetails: LastCommunicatedPlatformDetails,
+  +keyserverStore: KeyserverStore,
 };
 
 export type Action =