@ -209,8 +209,18 @@ new dynamic addresses, so any attacks against the first implementations have bee
Originally there were 4(!) implementations of Sietch in Hush world, 2 inside of `hushd` internals and 2 for `SilentDragonLite` which uses raw transactions and not the RPC interface of `z_sendmany`. Each of the 2 implementations has a static (drawing from a fixed pool of Sietch zaddrs) and a dynamic version (dynamically generating Sietch zaddrs at run-time). The static implementations went into production as of `Hush 3.3.0` and `SilentDragonLite 1.1.3`
## Frequenty Askes Questions
## Frequently Asked Questions
### Why do some Sietch tx's have only 3 shielded outputs?
z_shieldcoinbase, which shields coinbase (mining) funds, uses 3 outputs instead of the normal sietch ~8 zouts because it's trivial to see that it's not a normal z2z, because it has taddr inputs. Trying to blend in with other z2z tx's just won't work. So instead, metadata leakage is reduced by creating 3 shielded outputs (zouts) which makes it harder for attackers to figure things out. 8 outputs could have been used for these transactions as well, but that doesn't hide the fact that they are shielding mining funds, takes up more bytes on the blockchain and makes the transactions slower to create. The reason ~8 was a good choice for z2z tx's is because sometimes you are sending to a few addresses, and ~8 zouts hides that metadata leakage. But when you shield coinbase funds, you are always sending to a single address, so 3 zouts is sufficient.
## Does Sietch protect transactions with more than 8 outputs?
Currently it does not. Originally this question was asked roughly as "If a shielded tx has M outputs where M>8, will Sietch create a transaction with M+8 outputs?" The answer is "No" because that wouldn't actually reduce metadata leakage. For example, if you make a ztx with 10 outputs, and Sietch always turned that into 18 outputs, then an attacker would know there was originally 10 outputs and 8 were added. Always adding a fixed number of outputs does not reduce metadata leakage.
## Is it possible for Sietch to reduce metadata leakage on transactions with more than 8 outputs?
Yes. This will be implemented as a future improvement to how Sietch works.
