# Reverie - Optimized ZK proof system

**URL:** <https://forum.zcashcommunity.com/t/reverie-optimized-zk-proof-system/37966>\
**Category:** Technology\
**Created:** [December 15, 2020, 4:01am UTC](https://forum.zcashcommunity.com/t/reverie-optimized-zk-proof-system/37966 "2020-12-15T04:01:11Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![dontbeevil](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@dontbeevil](https://forum.zcashcommunity.com/u/dontbeevil)\
**Post date:** [December 15, 2020, 4:01am UTC](https://forum.zcashcommunity.com/t/reverie-optimized-zk-proof-system/37966/1 "2020-12-15T04:01:11Z")

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> **[Reverie: An optimized zero-knowledge proof system](https://blog.trailofbits.com/2020/12/14/reverie-an-optimized-zero-knowledge-proof-system/)**
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> Zero-knowledge proofs, once a theoretical curiosity, have recently seen widespread deployment in blockchain systems such as Zcash and Monero. However, most blockchain applications of ZK proofs make…

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**Author:** ![Shawn](https://sea2.discourse-cdn.com/zcash/user_avatar/forum.zcashcommunity.com/shawn/32/187_2.png) [@Shawn](https://forum.zcashcommunity.com/u/Shawn)\
**Post date:** [December 15, 2020, 1:31pm UTC](https://forum.zcashcommunity.com/t/reverie-optimized-zk-proof-system/37966/2 "2020-12-15T13:31:24Z")

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That’s an interesting use case, just skimming over the paper it looks like the proof sizes make it infeasible for a production blockchain like Zcash?

@str4d would probably know.

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**Author:** ![str4d](https://sea2.discourse-cdn.com/zcash/user_avatar/forum.zcashcommunity.com/str4d/32/64_2.png) [@str4d](https://forum.zcashcommunity.com/u/str4d)\
**Post date:** [December 15, 2020, 1:39pm UTC](https://forum.zcashcommunity.com/t/reverie-optimized-zk-proof-system/37966/3 "2020-12-15T13:39:31Z")

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Yeah, that’s way too big. Even if we assume the cost of a full Sapling-like spend circuit is equivalent to the cost of a single SHA-256 invocation, that’s still 220kB per proof.

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**Author:** ![secparam](https://sea2.discourse-cdn.com/zcash/user_avatar/forum.zcashcommunity.com/secparam/32/17461_2.png) [@secparam](https://forum.zcashcommunity.com/u/secparam)\
**Post date:** [December 15, 2020, 7:40pm UTC](https://forum.zcashcommunity.com/t/reverie-optimized-zk-proof-system/37966/4 "2020-12-15T19:40:37Z")

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Its too big. But what is the actual limit for TX size for a PoW consensus system?