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.
It may be suboptimal, but it's a pain to have to rebuild everything
when some of this changes.
Also, no clue why there seems to be two different code paths for
serializing a tx...
Pros:
- smaller on the blockchain
- shorter integrated addresses
Cons:
- less sparseness
- less ability to embed actual information
The boolean argument to encrypt payment ids is now gone from the
RPC calls, since the decision is made based on the length of the
payment id passed.
j-berman