Message: AddToInTxTracker

The AddToInTxTracker message handler is used to add an inbound transaction into the inbound transaction tracker. Non-observer and non-admin accounts are able to execute this message as long as they provide a proof for the transaction.

The code first ensures that either the caller of the handler is a policy type 1 admin account or an observer account or that a proof was supplied with the message.

If a proof is supplied, the proof itself is verified. The verification process differs between Bitcoin and Ethereum; however, in either case, external libraries are used, so we decided to treat that code as a black box.

Finally, the transaction is added into the store if it has successfully been proved or if a policy type 1 admin account or observer account executed the message.