asymmetric keys import/export

lib/KeyStore.ts

@@ -7,34 +7,66 @@
 
 import { generate_keypair } from '@sapphirecode/crypto-helper';
 
-interface Keypair {
-  private_key: string;
-  public_key: string;
-}
+const renew_interval = 60;
 
 interface Key {
-  key: Keypair;
+  key: string;
   valid_until: number;
-  timeout: NodeJS.Timeout;
 }
 
+interface KeyPair {
+  private_key?: Key;
+  public_key: Key;
+}
+
+type KeyStoreData = Record<string, KeyPair>;
+
 function get_index (iat: number): string {
-  return Math.floor (iat / 60)
+  return Math.floor (iat / renew_interval)
     .toFixed (0);
 }
 
-class KeyStore {
-  private _keys: Record<string, Key> = {};
+async function create_key (valid_for: number) {
+  const time = (new Date)
+    .getTime ();
+  const pair = await generate_keypair ();
+  return {
+    private_key: {
+      key:         pair.private_key,
+      valid_until: time + (renew_interval * 1000)
+    },
+    public_key: {
+      key:         pair.public_key,
+      valid_until: time + (valid_for * 1000)
+    }
+  };
+}
 
-  private set_timeout (index: string, valid_for: number): NodeJS.Timeout {
-    return setTimeout (() => {
-      delete this._keys[index];
-    }, (valid_for + 5) * 1000);
+function garbage_collect (set: KeyStoreData): void {
+  const time = (new Date)
+    .getTime ();
+  for (const index of Object.keys (set)) {
+    const entry = set[index];
+    if (typeof entry.private_key !== 'undefined'
+      && entry.private_key.valid_until < time
+    )
+      delete entry.private_key;
+    if (entry.public_key.valid_until < time)
+      delete set[index];
+  }
+}
+
+class KeyStore {
+  private _keys: KeyStoreData = {};
+  private _interval: NodeJS.Timeout;
+
+  public constructor () {
+    this._interval = setInterval (() => {
+      garbage_collect (this._keys);
+    }, renew_interval);
   }
 
   public async get_sign_key (iat: number, valid_for: number): Promise<string> {
-    const index = get_index (iat);
-
     if (valid_for <= 0)
       throw new Error ('cannot create infinitely valid key');
 
@@ -42,26 +74,21 @@ class KeyStore {
       .getTime ())
       throw new Error ('cannot access already expired keys');
 
+    const index = get_index (iat);
+
     const valid_until = (new Date)
       .getTime () + (valid_for * 1000);
 
     if (typeof this._keys[index] !== 'undefined') {
       const key = this._keys[index];
-      if (key.valid_until < valid_until) {
-        clearTimeout (key.timeout);
-        key.timeout = this.set_timeout (index, valid_for);
-        key.valid_until = valid_until;
-      }
-      return key.key.private_key;
+      if (key.public_key.valid_until < valid_until)
+        key.public_key.valid_until = valid_until;
+
+      return key.private_key?.key as string;
     }
 
-    this._keys[index] = {
-      key:     await generate_keypair (),
-      timeout: this.set_timeout (index, valid_for),
-      valid_until
-    };
-
-    return this._keys[index].key.private_key;
+    this._keys[index] = await create_key (valid_until);
+    return this._keys[index].private_key?.key as string;
   }
 
   public get_key (iat: number): string {
@@ -71,10 +98,26 @@ class KeyStore {
       throw new Error ('key could not be found');
 
     const key = this._keys[index];
-    return key.key.public_key;
+    return key.public_key.key;
+  }
+
+  public export_verification_data (): KeyStoreData {
+    garbage_collect (this._keys);
+    const out: KeyStoreData = {};
+    for (const index of Object.keys (this._keys))
+      out[index] = { public_key: this._keys[index].public_key };
+
+    return out;
+  }
+
+  public import_verification_data (data: KeyStoreData): void {
+    const import_set = { ...data };
+    garbage_collect (import_set);
+
+    // TODO: import
   }
 }
 
 const ks: KeyStore = (new KeyStore);
 export default ks;
-export { KeyStore };
+export { KeyStore, KeyStoreData, Key, KeyPair };

lib/index.ts

@@ -28,7 +28,7 @@ import create_gateway, {
   Gateway,
   AnyFunc
 } from './Gateway';
-import { KeyStore } from './KeyStore';
+import { KeyStore, KeyStoreData } from './KeyStore';
 
 export {
   create_gateway,
@@ -52,5 +52,6 @@ export {
   GatewayClass,
   Gateway,
   AnyFunc,
-  KeyStore
+  KeyStore,
+  KeyStoreData
 };