fhEVM v0.5: Enhanced Security and Efficiency for Encrypted Data

fhEVM v0.5 introduces significant advancements aimed at enhancing the security and efficiency of encrypted data handling in applications, notably through mechanisms such as packed input, an enhanced Access Control List (ACL), and updated decryption and re-encryption processes. The update allows multiple plaintext values to be packed into a single ciphertext, facilitating future developments like proven inputs, while the new ACL system provides robust management of ciphertext permissions, ensuring that only authorized entities can manipulate encrypted data. Security is further bolstered by the use of an off-chain service for re-encryption, optimizing cryptographic operations and allowing for batch decryption of multiple types. The release finalizes the Solidity API, ensuring compatibility across future versions and various blockchain platforms, and introduces a new permissions model and deprecates older functions in favor of updated methods. Additionally, fhEVM v0.5 is designed to accommodate future enhancements such as zero-knowledge proofs and new types, thus promoting long-term stability and broad usability for developing confidential smart contracts.