diff --git a/exercises/simple-cipher/example.js b/exercises/simple-cipher/example.js
index f3769fbc08..8e41b5d406 100644
--- a/exercises/simple-cipher/example.js
+++ b/exercises/simple-cipher/example.js
@@ -17,20 +17,23 @@ function xCode(key, inText, sign) {
 
 const mod = (n, m) => (n % m + m) % m;
 
-export default function (key) {
-  if (typeof key === 'undefined') {
-    key = generateKey();
-  } else if (key.length === 0 || key.match(/[^a-z]/, 'g')) {
-    throw new Error('Bad key');
+export class Cipher {
+
+  constructor (key) {
+    if (typeof key === 'undefined') {
+      this.key = generateKey();
+    } else if (key.length === 0 || key.match(/[^a-z]/, 'g')) {
+      throw new Error('Bad key');
+    } else {
+      this.key = key;
+    }
+  }
+
+  encode(plainText) {
+    return xCode(this.key, plainText, 1);
   }
 
-  return {
-    key,
-    encode(plainText) {
-      return xCode(this.key, plainText, 1);
-    },
-    decode(encodedText) {
-      return xCode(this.key, encodedText, -1);
-    },
-  };
+  decode(encodedText) {
+    return xCode(this.key, encodedText, -1);
+  }
 }
diff --git a/exercises/simple-cipher/simple-cipher.spec.js b/exercises/simple-cipher/simple-cipher.spec.js
index d3a9e48537..2f27067a17 100644
--- a/exercises/simple-cipher/simple-cipher.spec.js
+++ b/exercises/simple-cipher/simple-cipher.spec.js
@@ -1,4 +1,4 @@
-import Cipher from './simple-cipher';
+import { Cipher } from './simple-cipher';
 
 describe('Random key generation', () => {
   xtest('generates keys at random', () => {
@@ -56,6 +56,24 @@ describe('Incorrect key cipher', () => {
       new Cipher('');
     }).toThrow(new Error('Bad key'));
   });
+
+  xtest('throws an error with a leading space', () => {
+    expect(() => {
+      new Cipher(' leadingspace');
+    }).toThrow(new Error('Bad key'));
+  });
+
+  xtest('throws an error with a punctuation mark', () => {
+    expect(() => {
+      new Cipher('hyphened-word');
+    }).toThrow(new Error('Bad key'));
+  });
+
+  xtest('throws an error with a single capital letter', () => {
+    expect(() => {
+      new Cipher('leonardoDavinci');
+    }).toThrow(new Error('Bad key'));
+  });
 });
 
 describe('Substitution cipher', () => {