diff --git a/lib/winnow/matcher.rb b/lib/winnow/matcher.rb
index <HASH>..<HASH> 100644
--- a/lib/winnow/matcher.rb
+++ b/lib/winnow/matcher.rb
@@ -1,8 +1,10 @@
 module Winnow
   class Matcher
     class << self
-      def find_matches(fingerprints_a, fingerprints_b)
-        matched_values = fingerprints_a.keys & fingerprints_b.keys
+      def find_matches(fingerprints_a, fingerprints_b, params = {})
+        whitelist = params[:whitelist] || []
+
+        matched_values = fingerprints_a.keys & fingerprints_b.keys - whitelist
 
         value_match_pairs = matched_values.map do |value|
           matches_a, matches_b = fingerprints_a[value], fingerprints_b[value]
Ignore fingerprint values if they are in the whitelist.

This is useful if some fingerprint matches are expected and should be ignored.
If documents are expected to come from a template, then fingerprints from that
template should be added to the whitelist.