kmx.io/rbpkg

diff --git a/lib/rbpkg/sha256.rb b/lib/rbpkg/sha256.rb
index 0d069dd..2c5dce7 100644
--- a/lib/rbpkg/sha256.rb
+++ b/lib/rbpkg/sha256.rb
@@ -1,3 +1,5 @@
+require 'digest'
+
 class Rbpkg::SHA256
 
   def self.file(path)