CIP-0101 | Integration of keccak256 into Plutus

CIP-????/README.md

@@ -0,0 +1,65 @@
+---
+CIP: ?
+Title: Integration of `keccak256` into Plutus
+Status: Proposed
+Category: Plutus
+Authors: 
+  - Sergei Patrikeev <[email protected]>
+  - Iñigo Querejeta-Azurmendi <[email protected]>
+Implementors: []
+Discussions: 
+  - https://github.com/cardano-foundation/CIPs/pull/524
+Created: 2023-06-13
+License: Apache-2.0
+---
+
+## Abstract
+This CIP proposes an extension of the current Plutus functions to provide support for the [`keccak256`](https://keccak.team/files/Keccak-submission-3.pdf) hashing algorithm,
+primarily to ensure compatibility with Ethereum's cryptographic infrastructure.
+
+## Motivation: why is this CIP necessary?
+
+The [integration](https://github.com/cardano-foundation/CIPs/blob/master/CIP-0049/README.md) of the ECDSA and Schnorr signatures over the secp256k1 curve into Plutus was a significant 
+step towards interoperability with Ethereum and Bitcoin ecosystems. However, full compatibility is still impossible 
+due to the absence of the `keccak256` hashing algorithm in Plutus interpreter, 
+which is a fundamental component of Ethereum's cryptographic framework:
+- data signing standard [EIP-712](https://eips.ethereum.org/EIPS/eip-712), 
+- `keccak256` is the hashing algorithm underlying Ethereum's ECDSA signatures. 
+- EVM heavily [depends](https://ethereum.github.io/yellowpaper/paper.pdf) on `keccak256` for internal state management
+
+Adding `keccak256` to Plutus would enhance the potential for cross-chain solutions between Cardano and EVM-based blockchains.
+
+## Specification
+This proposal aims to introduce a new built-in hash function `keccak_256`.
+
+This function will be developed following the [`keccak256`](https://keccak.team/files/Keccak-submission-3.pdf) specification 
+and will utilize the [cryptonite](https://github.com/haskell-crypto/cryptonite/blob/master/Crypto/Hash/Keccak.hs) implementation. 
+Since `cryptonite` is already a part of the [`cardano-base`](https://github.com/input-output-hk/cardano-base/blob/master/cardano-crypto-class/src/Cardano/Crypto/Hash/Keccak256.hs), 
+this simplifies its integration into Plutus. The cost of the `keccak_256` operation will scale linearly with the length of the message.
+
+More specifically, Plutus will gain the following primitive operation:
+
+* `keccak_256` :: ByteString -> ByteString
+
+The input to this function can be a `ByteString` of arbitrary size, and the output will be a `ByteString` of 32 bytes. 
+Note that this function aligns with the format of existing hash functions in Plutus, such as [blake2b_256](https://github.com/input-output-hk/plutus/blob/75267027f157f1312964e7126280920d1245c52d/plutus-core/plutus-core/src/Data/ByteString/Hash.hs#L25)
+
+## Rationale: how does this CIP achieve its goals?
+While the `keccak256` function might be implemented in on-chain scripts, doing so would be computationally unfeasible. 
+
+## Path to Active
+This CIP may transition to active status once the Plutus version containing the `keccak_256` function is introduced 
+in a node release and becomes available on Mainnet.
+
+### Acceptance Criteria
+* A Plutus binding is created for the `keccak256` function and included in a new version of Plutus.
+* Integration tests, similar to those of the existing Plutus hash functions, are added to the testing infrastructure.
+* The function is benchmarked to assess its cost.
+* E2E tests with real use cases are incorporated into the testing infrastructure.
+
+### Implementation Plan
+The Plutus team will develop the binding, integration tests, and benchmarks. The E2E tests will be designed and implemented 
+collaboratively by the testing team, the Plutus team, and community members planning to use this primitive.
+
+## Copyright
+This CIP is licensed under [Apache-2.0][https://www.apache.org/licenses/LICENSE-2.0].