A bug in cold signing caused a spurious pubkey to be included
in transactions, so we need to ensure we use the correct one
when sending outputs from one of those.
The vast majority of transactions will have just one tx pubkey,
but a bug with cold wallet signing caused two such keys to be
there, with the second one being the real one.
Compute derivation only once per tx, instead of once per output. Approx 33% faster while using 75% as much CPU on my machine. Note old functions in cryptonote_core (lookup_acc_outs and is_out_to_acc) are still used by tests.
This change adds the ability to create a new unsigned transaction
from a watch only wallet, and save it to a file. This file can
then be moved to another computer/VM where a cold wallet may load
it, sign it, and save it. That cold wallet does not need to have
a blockchain nor daemon. The signed transaction file can then be
moved back to the watch only wallet, which can load it and send
it to the daemon.
Two new simplewallet commands to use it:
sign_transfer (on the cold wallet)
submit_transfer (on the watch only wallet)
The transfer command used on a watch only wallet now writes an
unsigned transaction set in a file called 'unsigned_monero_tx'
instead of submitting the tx to the daemon as a normal wallet does.
The signed tx file is called 'signed_monero_tx'.
When RingCT is enabled, outputs from coinbase transactions
are created as a single output, and stored as RingCT output,
with a fake mask. Their amount is not hidden on the blockchain
itself, but they are then able to be used as fake inputs in
a RingCT ring. Since the output amounts are hidden, their
"dustiness" is not an obstacle anymore to mixing, and this
makes the coinbase transactions a lot smaller, as well as
helping the TXO set to grow more slowly.
Also add a new "Null" type of rct signature, which decreases
the size required when no signatures are to be stored, as
in a coinbase tx.
This allows the key to be not the same for two outputs sent to
the same address (eg, if you pay yourself, and also get change
back). Also remove the key amounts lists and return parameters
since we don't actually generate random ones, so we don't need
to save them as we can recalculate them when needed if we have
the correct keys.
The tests for rejection of unmixable outputs in v2 are commented out,
as there are no unmixable outputs created anymore. This should be
restored at some point.
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.
A payment ID may be encrypted using the tx secret key and the
receiver's public view key. The receiver can decrypt it with
the tx public key and the receiver's secret view key.
Using integrated addresses now cause the payment IDs to be
encrypted. Payment IDs used manually are not encrypted by default,
but can be encrypted using the new 'encrypt_payment_id' field
in the transfer and transfer_split RPC calls. It is not possible
to use an encrypted payment ID by specifying a manual simplewallet
transfer/transfer_new command, though this is just a limitation
due to input parsing.
