# Proof of space performance improvements by sharing tables between pieces **URL:** \ **Category:** Research\ **Tags:** consensus, proof-of-space, performance, chia\ **Created:** [July 22, 2023, 4:47pm UTC](https://forum.autonomys.xyz/t/proof-of-space-performance-improvements-by-sharing-tables-between-pieces/1585 "2023-07-22T16:47:03Z")\ **Posts on this page:** 1\ **Showing post:** 29
**Author:** ![Chen\_Feng\_2023](https://avatars.discourse-cdn.com/v4/letter/c/e56c9b/32.png) [@Chen\_Feng\_2023](https://forum.autonomys.xyz/u/Chen_Feng_2023)\ **Post date:** [August 4, 2023, 8:08pm UTC](https://forum.autonomys.xyz/t/proof-of-space-performance-improvements-by-sharing-tables-between-pieces/1585/29 "2023-08-04T20:08:52Z")
To provide some additional insight on this topic, let us revisit the security foundations for Chia and Subspace. Loosely speaking, the foundation for Chia can be stated as: Given massive honest storage space \Omega, it is hard for the adversary to “match” the space \Omega (so that the adversary can do double-spending) in terms of the space-time tradeoff even with near-optimal strategies such as Hellman’s attacks. This foundation applies to Subspace as discussed in our [research paper](https://forum.autonomys.xyz/t/research-style-paper-on-subspace-consensus/1192). But more importantly, Subspace enjoys an additional security foundation: Given massive honest storage space \Omega, it is hard for the adversary to “match” the space \Omega (so that the adversary can do double-spending) in terms of the **space-time-IO** tradeoff under various strategies. In other words, the required IO for many attacks is too demanding for large \Omega. Next, let us use on-demand plotting as a particular example of attacking strategies. As explained by Dariia, the IO of k22 is about four times the IO of k20. So, we can mask 4 pieces with k22. which does not give the adversary conducting on-demand plotting any advantage in terms of required IO. In other words, k22 with masking 4 pieces is as good as k20 with masking 1 piece for on-demand plotting. --- _[View the full topic](https://forum.autonomys.xyz/t/proof-of-space-performance-improvements-by-sharing-tables-between-pieces/1585)._