diff --git a/Cryptography & Privacy.playgroundbook/Contents/Chapters/Chapter1.playgroundchapter/Pages/Symmetric-Key Cryptography.playgroundpage/Contents.swift b/Cryptography & Privacy.playgroundbook/Contents/Chapters/Chapter1.playgroundchapter/Pages/Symmetric-Key Cryptography.playgroundpage/Contents.swift
index e17f3e0..e5043c9 100644
--- a/Cryptography & Privacy.playgroundbook/Contents/Chapters/Chapter1.playgroundchapter/Pages/Symmetric-Key Cryptography.playgroundpage/Contents.swift	
+++ b/Cryptography & Privacy.playgroundbook/Contents/Chapters/Chapter1.playgroundchapter/Pages/Symmetric-Key Cryptography.playgroundpage/Contents.swift	
@@ -5,6 +5,8 @@
 //  Abstract:
 //  The Swift file containing the source code edited by the user of this playground book.
 //
+import Foundation
+import PlaygroundSupport
 //#-end-hidden-code
 /*:
 # Symmetric-Key Cryptography