Add an action to derive the encryption key.

src/store/actions.ts

@@ -31,6 +31,13 @@ export const { fetchCredentials, logout } = createActions({
   LOGOUT: () => undefined,
 });
 
+// FIXME: This is duplicating behaviour from the fetchCredentials above
+export const { deriveKey } = createActions({
+  DERIVE_KEY: (username: string, encryptionPassword: string) => {
+    return EteSync.deriveKey(username, encryptionPassword);
+  },
+});
+
 export const { fetchJournals } = createActions({
   FETCH_JOURNALS: (etesync: CredentialsData) => {
     const creds = etesync.credentials;

src/store/reducers.ts

@@ -90,6 +90,9 @@ const encryptionKeyReducer = handleActions(
         return {key: action.payload.encryptionKey};
       }
     },
+    [actions.deriveKey.toString()]: (state: {key: string | null}, action: any) => (
+      {key: action.payload}
+    ),
     [actions.logout.toString()]: (state: {key: string | null}, action: any) => {
       return {out: true, key: null};
     },