# Programmable Cryptography and Smart Contract by Shouki Tsuda | Devcon SEA

- Speakers: [Shouki Tsuda](https://streameth.org/speakers/shouki-tsuda)
- Channel: [Devcon](https://streameth.org/devcon)
- Date: 2025-10-09
- Duration: 05:55
- Topics: Science & Technology
- Watch: https://streameth.org/watch/yt-j9YnU1-MeiU
- YouTube: https://www.youtube.com/watch?v=j9YnU1-MeiU

## Description

Overview
In some use cases, developers may want to execute smart contracts based on the results of FHE or MPC execution. This session will introduce several design patterns for such use cases and show how Programmable Cryptography can be applied to dApps.

In detail
The results of FHE executions are encrypted and need to be designed to be processed by smart contracts. In addition, the MPC+ZK-based method can solve the private state problem relatively easily using the conventional SNARK verifier.

Speaker(s): Shouki Tsuda
Skill level: Beginner
Track: Developer Experience
Keywords: DevEx, Cryptography, MPC, programmable

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## Transcript

[Music] so today I want talking about my current research program cryptography and smart contract so program cryptography is more flexible than traditional cryptography Styles like uh RC so this time I'm talking about how to run smart contract based on uh offchain execution by zkp and secure Computing at first let's talk about zkp and smart contract so it is easy to integrate with smart contract because we have a solier which en to uh produce a verifier contract so we can verify the zkp on chain and transfer asset to any other appr or something like that and so we can combine with zkp and FH and NPC and produce a veriable computation I will talking about this later yeah so this section I am talking about how to integrate with f smart contract the basic principle of fhe is encrypted evaluation and only F can de is just client so it is difficult to integrate with smart contract by default if we using smart contract we need to share the encryp result and uh also decretion Key by client side but it does not make sense to achieve the secure Computing right but somehow we have a solution to combine with gkp or NPC so verifiable FH is a kind of technique to prove the FH evaluation and we can verify it on chain as I mention before we can use a cier and m is little bit different concept it's spit the decretion key and share it to the third party like a smart contract whatever both of two stuff is so cool but somehow it is difficult to integrate the smart contract on top of the proof of time and data problem okay so next section is how to integrate NPC and smart contract the concept of NPC is uh evalu collaboratory so each party share on bits of uh confidential data and cabor evaluate it and compose it to get the result so in this time we don't integrate with smart contract however I think you can imagine how to solve this problem you know we can combine with zkp or F like that so verifiable NPC is similar concept of verifiable fhe so we can prove the execution of NPC and verify it uh by smart contract using a b 3D verier also collaborative snack is similar to B NPC because we combine the dkp and NPC but this is different from you know uh in term of cor snacks uh this is just generate proof collaborat so user Ena to delegate the proving to NPC okay so let's wrap up my session uh I introduce how to run the smart contract by uh offchain execution of program cryptography and main idea is using the Sol verifier and on verification also we can combine with uh each Primitives to overcome the con or some Primitives so program cryptography is so cool and we can ower the isum and blockchain Technology as well and I think it is is uh we need to more uh try to some issue as I mentioned before like approving time or datas problem yeah that's it thank you thank you shi for the session do we have questions for our speaker no question oh good h I sorry I forgot my volleyball lessons yeah I wanted to understand uh what other implementations are there like any use cases or example where F yeah uh one of the big FH is use case is kind of evaluation of uh stats like offchain stats like a bank account or GPA or something like that I think next question okay next question okay all right since there's no more question I love to give some break you know when the classroom stands like this you need to allow people to have some time so please you can get up