Fresh Crypto Lib (FCL)

The Fresh Crypto Lib is a set of functions for blockchain systems such as Wallet, SmartContracts.

*** 15/05/24 : Deprecated

*** This library is an experimental prequel of SCL. SCL proposes more generic implementation with RIP7696 for lesser cost (beating record set by FCL) and is currently under audit. https://github.com/get-smooth/crypto-lib.

*** new (27/05/24): SCL now supports both Ed25519 and P256 using RIP7696.

*** new (06/08/24): SCL first audit completed, second VERIDISE audit being reviewed (FCL has no audit).

*** We warmly thanks all contributors of FCL, they will be added as contributor to SCL.

Content

The implemented content is:

• sec256r1 optimizations for EVM chains and Starknet
• an ecdaa implementation using blockchain primitives
• a Starknet dedicated musig2 implementation

Directory solidity:

• FCL_ecdsa.sol: an EVM optimized implementation of ecdsa over sec256r1(P256), using language hacks and specificities, as described in paper https://eprint.iacr.org/2023/939.pdf.
• FCL_eddsa.sol : an EVM optimized implementation of ed25519, using same paper tricks.
• FCL_sha512.sol : implementation of the SHA512 primitive (single bloc implementation)
• FLC_Webauthn.sol: implementation of the WebAuthn2/FIDO2 authentication over ECDSA with P256

<!--- FCL_ecdaa.sol: an EVM version of the ECDAA anonymous attestation for anonymous airdrops -->

| PR # | Create2 | Mainnets | Testnets | |--------:|---------|:--:|:----| || | | | |46| 0xE9399D1183a5cf9E14B120875A616b6E2bcB840a | Polygon | Optimism, Sepolia, Linea |

(code is verified except for linea, one could check that bytecode is identical).

Directory cairo0.9:

• FCL_ec_mulmuladd.cairo: an implementation of the operation aP+bQ (addition of the results of two distincts point multiplication by scalar a and b). It uses the Shamir's trick with the windowing method. signature_opt.cairo : optimisation of ECDSA verification using ec_mulmuladd_W function

<!---* FCL_cairo_secp : optimization of the ECDSA function over sec256r1, using starkware implementation with ec_mulmuladdW_sec256k1 (original implementation from Starkware commons here:https://github.com/https://github.com/starkware-libs/cairo-lang/tree/master/src/starkware/cairo/common/cairo_secp)--> <!---* FCL_cairo_secp256k1 : optimization of the ECDSA function over sec256k1 using ec_mulmuladdW_sec256r1 (original implementation from Cartridge here:https://github.com/cartridge-gg/cairo-secp256r1) --> <!---*FCL_musig2: Original implementation of the Schnorr verification algorithm. Please note that it is a custom implementation (cryptographically equivalent, but not identical to BlockStream implementation). Namely arbitrary domain separator, choice of hash, byte ordering and annoying little choices are not compatible with Musig2 BIP proposal.-->

Note : The language is now deprecated since its transition from python-like to rust-like language.

Directory sage:

• FCL_ecdsa_precompute.sage : precompute bytecode contract to speed up ecdsa verification for a given key.
• FCL_ecdaa : sage reference for a blockchain implementation of ECDAA
• FCL_pairings : sage implementation of curve and pairing computation over BN254 (aka altbn128) and BLS12381 using INRIA sources.

Acknowledments:

Building Blocks

The following repos are used as building blocks in the FCL:

• Aurore Guillevic's Gitlab at INRIA: https://gitlab.inria.fr/tnfs-alpha/alpha/-/tree/190b87732901750ed1438a8cf340571531d32230/sage/tnfs for its generic sagemath BN and BLS curves and pairing implementation.
• Paul Miller Noble javascript library for its G1 implementation of BN254 and BLS12, and keccak256. https://paulmillr.com/noble/

Benchmark

The following repos have been used in benchmarks:

• Alembic/cometh:https://github.com/alembic-tech/P256-verify-signature/blob/main/contracts/EllipticCurve.sol
• MaxRobot : https://github.com/maxrobot/elliptic-solidity
• Numerology : https://github.com/nucypher/numerology
• Obvious : https://github.com/itsobvioustech/aa-passkeys-wallet

Testing

• Invariant test vectors are extracted from the wycheproof project : https://github.com/google/wycheproof

FCL in the wild

• Academic paper: https://eprint.iacr.org/2023/939 for EthCC2023
• Alembic : https://github.com/alembic-tech/p256-signer/blob/main/contracts/FCL/FCL_elliptic.sol
• Base Smart Wallet: fast onboarding using FCL: https://www.smart-wallet.xyz/, deployed at 0x0BA5ED0c6AA8c49038F819E587E2633c4A9F428a (Base main and Sepolia)
• Braavos https://github.com/myBraavos/efficient-secp256r1/blob/develop/src/secp256r1/ec_mulmuladd.cairo
• Cartridge https://github.com/cartridge-gg/cairo-secp256r1/pull/3
• EIP665 PR#7515 :https://github.com/ethereum/EIPs/pull/7515
• Presentation made at EthCC 2023 in Paris: https://www.youtube.com/live/Rlq21oA_FA8
• Forum DAO, :https://github.com/forumdaos/forum-contracts/tree/main/src/libraries
• Daimo, ethereum payments : https://github.com/daimo-eth/p256-verifier/blob/master/src/P256Verifier.sol
• Safe : https://github.com/safe-global/safe-modules/tree/master/4337/contracts/test/FCL
• SoulWallet : https://github.com/SoulWallet/soul-wallet-contract/blob/a0146910dfbc46afeba809b26f256129d37e3301/contracts/libraries/WebAuthn.sol#L69
• Wallet Abstraction, EthGlobal NY hackathon finalist : https://github.com/qd-qd/wallet-abstraction
• Wax : Wallet Account Experiments, PSE team (EF funded) https://github.com/getwax/wax/commit/fd246685f67ebb56f5ebb82cb48df56088e28c7b

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License

License: This software is licensed under MIT License (see LICENSE FILE at root directory of project).