Keccak256

The OpenVM Keccak256 guest library provides two functions for use in your guest code:

• keccak256(input: &[u8]) -> [u8; 32]: Computes the Keccak-256 hash of the input data and returns it as an array of 32 bytes.
• set_keccak256(input: &[u8], output: &mut [u8; 32]): Sets the output to the Keccak-256 hash of the input data into the provided output buffer.

See the full example here.

Example

use core::hint::black_box;

use hex::FromHex;
use openvm_keccak256::keccak256;
openvm::entry!(main);

pub fn main() {
    let test_vectors = [
        (
            "",
            "C5D2460186F7233C927E7DB2DCC703C0E500B653CA82273B7BFAD8045D85A470",
        ),
        (
            "CC",
            "EEAD6DBFC7340A56CAEDC044696A168870549A6A7F6F56961E84A54BD9970B8A",
        ),
    ];
    for (input, expected_output) in test_vectors.iter() {
        let input = Vec::from_hex(input).unwrap();
        let expected_output = Vec::from_hex(expected_output).unwrap();
        let output = keccak256(&black_box(input));
        if output != *expected_output {
            panic!();
        }
    }
}

To be able to import the keccak256 function, add the following to your Cargo.toml file:

openvm-keccak256 = { git = "https://github.com/openvm-org/openvm.git" }
hex = { version = "0.4.3" }

Config parameters

For the guest program to build successfully add the following to your .toml file:

[app_vm_config.keccak]