diff --git a/lib/picopackage/cli.rb b/lib/picopackage/cli.rb
index cf59495..a3fe795 100644
--- a/lib/picopackage/cli.rb
+++ b/lib/picopackage/cli.rb
@@ -15,13 +15,13 @@ module Picopackage
         dir = argv.first || '.'
         Picopackage::Scanner.scan(dir).each {|f| puts f.file_path }
 
-      when 'sign'
+      when 'digest'
         OptionParser.new do |opts|
-          opts.banner = "Usage: ppkg sign FILE"
+          opts.banner = "Usage: ppkg digest FILE"
         end.parse!(argv)
 
         file = argv.first
-        Picopackage::SourceFile.from_file(file).sign
+        Picopackage::SourceFile.from_file(file).digest!
 
       when 'checksum'
         OptionParser.new do |opts|
diff --git a/lib/picopackage/fetch.rb b/lib/picopackage/fetch.rb
index 00210af..a32a044 100644
--- a/lib/picopackage/fetch.rb
+++ b/lib/picopackage/fetch.rb
@@ -34,7 +34,7 @@ module Picopackage
       else
         source_file.save(destination)
         if source_file.imported?
-          source_file.sign
+          source_file.digest!
           puts "Picopackage created for #{source_file.filename}"
         else
           puts "Picopackage downloaded to #{file_path}"
diff --git a/lib/picopackage/source_file.rb b/lib/picopackage/source_file.rb
index 542bdad..ba0508f 100644
--- a/lib/picopackage/source_file.rb
+++ b/lib/picopackage/source_file.rb
@@ -15,7 +15,7 @@ module Picopackage
 
       updated_metadata = metadata.merge(instance.metadata)
 
-      ## For new Picopackages, we should add metadata and sign
+      ## For new Picopackages, we should add metadata and checksum
       instance.update_metadata(updated_metadata)
 
       instance
@@ -68,9 +68,9 @@ module Picopackage
       @content = generate_content
     end
     
-    def sign
+    def digest!
       hash = checksum
-      return puts "File already signed" if metadata['content_checksum'] == hash
+      return puts "File already has a checksum" if metadata['content_checksum'] == hash
   
       new_metadata = metadata.merge('content_checksum' => hash)
       update_metadata(new_metadata)