Author: Peter R 2016-05-09 18:34:47
Published on: 2016-05-09T18:34:47+00:00
Pieter explains the length of short IDs required, using an equation to find the number of bits needed for any reasonable numbers. He suggests that 5 or 6 byte txids should be enough for most cases, but it makes sense to allow the sender to choose. He also mentions that occasional failures shouldn't affect global propagation, and that transmission failures occur more frequently than once every few gigabytes. Another technique for further reducing the number of bytes used for the txids is discussed in context of "Xthin" for Bitcoin Unlimited, which uses all possible orderings for each subset. The Shannon entropy (the information that must be communicated) is the base-2 logarithm of the number of possible blocks. After making some approximations, Pieter calculates that a lower bound on the information required is about 2 bytes per transaction for every transaction in the block that the node already knows, as well as all the missing transactions in full.
Updated on: 2023-06-11T04:51:43.737332+00:00