Add view tags to outputs to reduce wallet scanning time

Implements view tags as proposed by @UkoeHB in MRL issue
https://github.com/monero-project/research-lab/issues/73

At tx construction, the sender adds a 1-byte view tag to each
output. The view tag is derived from the sender-receiver
shared secret. When scanning for outputs, the receiver can
check the view tag for a match, in order to reduce scanning
time. When the view tag does not match, the wallet avoids the
more expensive EC operations when deriving the output public
key using the shared secret.

1 files changed, 12 insertions, 1 deletions

diff --git a/src/cryptonote_basic/cryptonote_boost_serialization.h b/src/cryptonote_basic/cryptonote_boost_serialization.h
index d7149b5c9..493c9d91d 100644
--- a/src/cryptonote_basic/cryptonote_boost_serialization.h
+++ b/src/cryptonote_basic/cryptonote_boost_serialization.h
@@ -71,7 +71,11 @@ namespace boost
   {
     a & reinterpret_cast<char (&)[sizeof(crypto::key_image)]>(x);
   }
-
+  template <class Archive>
+  inline void serialize(Archive &a, crypto::view_tag &x, const boost::serialization::version_type ver)
+  {
+    a & reinterpret_cast<char (&)[sizeof(crypto::view_tag)]>(x);
+  }
   template <class Archive>
   inline void serialize(Archive &a, crypto::signature &x, const boost::serialization::version_type ver)
   {
@@ -103,6 +107,13 @@ namespace boost
   }
 
   template <class Archive>
+  inline void serialize(Archive &a, cryptonote::txout_to_tagged_key &x, const boost::serialization::version_type ver)
+  {
+    a & x.key;
+    a & x.view_tag;
+  }
+
+  template <class Archive>
   inline void serialize(Archive &a, cryptonote::txout_to_scripthash &x, const boost::serialization::version_type ver)
   {
     a & x.hash;