fix(core): update

ts/smartjwt.classes.smartjwt.ts

@@ -1,7 +1,12 @@
 import * as plugins from './smartjwt.plugins';
 
+export interface ISmartJWTJSONKeypair {
+  privatePem: string;
+  publicPem: string;
+}
+
 /**
- * 
+ * A class to create and validate JWTs and their keys
  */
 export class SmartJwt {
   public smartcryptoInstance = new plugins.smartcrypto.Smartcrypto();
@@ -42,6 +47,24 @@ export class SmartJwt {
     this.publicKey = publicKey;
   }
 
+  /**
+   * gets the currently set kaypair as json
+   */
+  public getKeyPairAsJson(): ISmartJWTJSONKeypair {
+    return {
+      privatePem: this.privateKey.toPemString(),
+      publicPem: this.publicKey.toPemString()
+    };
+  }
+
+  /**
+   * sets the currently set keypair as json
+   */
+  public setKeyPairAsJson(jsonKeyPair: ISmartJWTJSONKeypair) {
+    this.privateKey = plugins.smartcrypto.PrivateKey.fromPemString(jsonKeyPair.privatePem);
+    this.publicKey = plugins.smartcrypto.PublicKey.fromPemString(jsonKeyPair.publicPem);
+  }
+
 
   /**
    * creates a new keypair