Notes on Zcash

How do receipients of shielded transactions (between z-addrs) detect the new ZEC they receive?

They need to run indexers.

Pains: this is very slow for the average user.

Understanding:

• zcash is comprised of notes.
• for example, a note with 10 ZEC
• these notes are in a global note commitment tree
• the transaction:
  • prove existence of note
  • now spend the value of the note into multiple new output notes

protocol notes:

• in-band encryption to securely transmit (amount) to receipient of funds
  • maybe wallet iterates over all txs to

https://forum.zcashcommunity.com/t/warp-sync-a-full-scan-method/39462

A shielded payment address includes a transmission key for a “key-private” asymmetric encryption scheme.

Key-private means that ciphertexts do not reveal information about which key they were encrypted to, except to a holder of the corresponding private key , which in this context is called the receiving key .

This facility is used to communicate encrypted output notes on the block chain to their intended recipient, who can use the receiving key to scan the block chain for notes addressed to them and then decrypt those notes.

The basis of the privacy properties of Zcash is that when a note is spent, the spender only proves that some commitment for it had been revealed, without revealing which one. This implies that a spent note cannot be linked to the transaction in which it was created. That is, from an adversary’s point of view the set of possibilities for a given note input to a transaction —its note traceability set — includes all previous notes that the adversary does not control or know to have been spent.

Recipients of a shielded or deshielding transaction do not learn about the senders address through the transaction recipt in their wallet. The receivers only learn the value sent to their address(es) and if receiving to shielded addresses, any encrypted memo that may have been included by the sender