O1JS SHA256 Hash Function Circuit

This project uses the o1js SDK to optimize the SHA256 circuit implementation by operating on the 32-bit words(32 field elements) as a single field element utilizing native binary gadgets.

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Using efficient binary hash function inside zk circuits

The native binary gadgets in O1JS are hard-coded to operate on 64-bit Field elements which made it not practical to develop SHA256 swiftly.
The rotate, shift, and rangeCheck functions in o1js are not flexible and only operate on 64-bit field elements.
I tried to simulate the bitwise functions as in sha256 circuit in circomlib but I hadn't enough time to debug and make things work correctly.
The library is quite rich but I sometimes spend a lot of time trying to find documentation for certain API.
Working with a DSL used a TS framework made practical and flexible to implement logic and have a development experience similar to normal TS language, but sometimes I feel that I am a bit lost distinguishing circuit logic from the normal TS logic, Other DSL having kind of different language helped me before to have a clearer mental model.
It would have been better to have a better documentation in general to save time from reading and looking at the source code intensively.

Tracks Applied (2)

The SHA256 implementation using the O1JS SDK will help pave the way to the use of more cryptographic schemes and protoco...Read More

O(1)Labs

I tried to use a complex and important cryptographic primitive using a new SDK. O1JS is good and I can see it refined mo...Read More

Technologies used

Zero-Knowledge Proofs (ZKPs)

SHA-256 Hashes

O1JS SDK

Discussion