fhEVM v0.3: New Stack and Better Performances

This new version of Zama's fhEVM introduces a new technical stack and the first release of fhevm-go. Performance improvements are expected with the updated TFHE-rs version. Additionally, there's an early version of a centralized Key Management System (KMS) now available, enabling validators to decrypt without needing local decryption keys.

New blockchain stack

Design change

We are launching fhevm-go that allows easier integrations in go-ethereum based blockchains. This refactor isolates the FHE operations library from the integration part to allow for easier to maintain and cleaner code.

Migration

We are switching from evmos 0.9 to a new stack with:

go-ethereum v1.13.5
ethermint (forked from the latest open-source version)
CometBFT
TFHE-rs v0.4.1

This new stack is already available on our: https://devnet.zama.ai.

Compatibility with Shanghai VM

fhEVM v0.3 is now compatible with Solidity ^0.8.20 (Shanghai EVM).

Operation cost and new features

fhEVM v0.3 uses the native TFHE-rs CMUX operator which is way faster than the previous one.

fhEVM v0.3 adds a simulation mode for faster development that mocks every FHE operation (read more in the documentation). The whole test suite takes 4 seconds in mocked mode instead of 21 minutes. Another advantage is that this mode allows to compute tests coverage, improving security best practices.

Details of Gas estimations for each operation

We’ve updated gas prices to reflect more the underlying performance. Thanks to the new version of TFHE-rs we are using and its performance, we manage to reduce gas costs for some operations like [.c-inline-code]TFHE.div[.c-inline-code] and [.c-inline-code]TFHE.rem[.c-inline-code].

Function Name	ebool/euint8	euint16	euint32
TFHE.add/TFHE.sub	120,000	150,000	180,000
TFHE.add/TFHE.sub (Scalar)	120,000	150,000	180,000
TFHE.mul	200,000	260,000	380,000
TFHE.mul (Scalar)	135,000	140,000	170,000
TFHE.and/TFHE.or/TFHE.xor	30,000	33,000	36,000
TFHE.div (Scalar)	450,000	500,000	550,000
TFHE.shr/TFHE.shl	150,000	180,000	210,000
TFHE.shr/TFHE.shl (Scalar)	32,000	32,000	32,000
TFHE.eq/TFHE.ne/TFHE.ge/TFHE.le/TFHE.gt/TFHE.lt	56,000	67,000	89,000
TFHE.eq/TFHE.ne/TFHE.ge/TFHE.le/TFHE.gt/TFHE.lt (Scalar)	56,000	67,000	89,000
TFHE.min/TFHE.max	220,000	280,000	340,000
TFHE.min/TFHE.max (Scalar)	140,000	165,000	190,000
TFHE.neg/TFHE.not	29,000	31,000	33,000
TFHE.cmux	60,000	65,000	70,000
TFHE.decrypt()	500,000	500,000	500,000
TFHE.randEuintX()	100,000	100,000	100,000