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.
When additional keys was needed, the TX scan failed because the
derivation data was always recomputed with the main tx_key and not
the corresponding additional one.
Moreover this patch avoid perf decreasing when not using HW device.
On client startup the device asks for authorization to export the private view key.
If user agree, the client hold the private view key allowing a fast blockchain scan.
If the user does not agree, the blockchain scan is fully done via the device.
When #3303 was merged, a cyclic dependency chain was generated:
libdevice <- libcncrypto <- libringct <- libdevice
This was because libdevice needs access to a set of basic crypto operations
implemented in libringct such as scalarmultBase(), while libringct also needs
access to abstracted crypto operations implemented in libdevice such as
ecdhEncode(). To untangle this cyclic dependency chain, this patch splits libringct
into libringct_basic and libringct, where the basic crypto ops previously in
libringct are moved into libringct_basic. The cyclic dependency is now resolved
thanks to this separation:
libcncrypto <- libringct_basic <- libdevice <- libcryptonote_basic <- libringct
This eliminates the need for crypto_device.cpp and rctOps_device.cpp.
Also, many abstracted interfaces of hw::device such as encrypt_payment_id() and
get_subaddress_secret_key() were previously implemented in libcryptonote_basic
(cryptonote_format_utils.cpp) and were then called from hw::core::device_default,
which is odd because libdevice is supposed to be independent of libcryptonote_basic.
Therefore, those functions were moved to device_default.cpp.
Fix the way the REAL mode is handle:
Let create_transactions_2 and create_transactions_from construct the vector of transactions.
Then iterate on it and resign.
We just need to add 'outs' list in the TX struct for that.
Fix default secret keys value when DEBUG_HWDEVICE mode is off
The magic value (00...00 for view key and FF..FF for spend key) was not correctly set
when DEBUG_HWDEVICE was off. Both was set to 00...00.
Add sub-address info in ABP map in order to correctly display destination sub-address on device
Fix DEBUG_HWDEVICE mode:
- Fix compilation errors.
- Fix control device init in ledger device.
- Add more log.
Fix sub addr control
Fix debug Info
The basic approach it to delegate all sensitive data (master key, secret
ephemeral key, key derivation, ....) and related operations to the device.
As device has low memory, it does not keep itself the values
(except for view/spend keys) but once computed there are encrypted (with AES
are equivalent) and return back to monero-wallet-cli. When they need to be
manipulated by the device, they are decrypted on receive.
Moreover, using the client for storing the value in encrypted form limits
the modification in the client code. Those values are transfered from one
C-structure to another one as previously.
The code modification has been done with the wishes to be open to any
other hardware wallet. To achieve that a C++ class hw::Device has been
introduced. Two initial implementations are provided: the "default", which
remaps all calls to initial Monero code, and the "Ledger", which delegates
all calls to Ledger device.
