- get_tx_key supports retrieval of private tx keys - required by users to check the transaction or when resolving disputes with the decipient
- get_tx_key supports to return transaction derivations = private tx key * public view key. This enables to compute tx_proof for outgoing transactions which is also a nice tool when resolving disputes, provides better protection as tx private key is hidden.
- live refresh enables computation of key images on the fly during the refresh. This helps to completely avoid key image sync and enables to use the Trezor with untrusted node.
- uses protobuff messages only for the transaction construction data - forward compatible. Not stable on Monero side, serialization format of the cryptonote serialization could be changed in the future (new fields), CN serialization does not support versioning, thus it is not forward compatible.
- MoneroTransactionDestinationEntry, MoneroTransactionSourceEntry have to be defined in the root level as they are used in various protocol messages
