+Three functions are exported by this module, all by default:
+
+=over
+
+=item B<highway_hash64> I<\@key>, I<$input>
+
+Compute the 64-bit HighwayHash of I<$input>, using I<\@key> as a key.
+The key must be a 4-element arrayref, with each element either a
+number or (on Perls without 64-bit numbers) a L<Math::Int64> object. The result is a single number or (on Perls without 64-bit numbers) a L<Math::Int64> object.
+
+=item B<highway_hash128> I<\@key>, I<$input>
+
+Compute the 128-bit HighwayHash of I<$input>, using I<\@key> as a key.
+The key must be a 4-element arrayref, with each element either a
+number or (on Perls without 64-bit numbers) a L<Math::Int64> object. The result is an array of exactly two numbers or (on Perls without 64-bit numbers) L<Math::Int64> objects.
+
+=item B<highway_hash256> I<\@key>, I<$input>
+
+Compute the 256-bit HighwayHash of I<$input>, using I<\@key> as a key.
+The key must be a 4-element arrayref, with each element either a
+number or (on Perls without 64-bit numbers) a L<Math::Int64> object. The result is an array of exactly four numbers or (on Perls without 64-bit numbers) L<Math::Int64> objects.
+
+
+=back
+