Historeum, previously known as Caerus, is a Layer-2 solution built on Ethereum. It features a time-aware EVM (Ethereum Virtual Machine) that enables smart contracts to access historical on-chain data efficiently.
🌐 https://caerus-chain.github.io/webapp/
- Archive-powered EVM: Integrates Archive Storage with the EVM, providing direct on-chain access to historical data.
- Solidity Extension: The modified Solidity compiler allows developers to query and use historical data in smart contracts.
- Versatile Applicability: Ideal for various blockchain ecosystems, especially in reputation systems and financial services where historical data is essential.
Historeum is built using the Optimism OP Stack, a modular framework that enhances scalability and efficiency. We've customized the OP Stack to integrate seamlessly with our time-aware EVM, enabling direct on-chain access to historical data.
Historeum extends the Ethereum Virtual Machine by adding functionalities that allow direct access to historical data, eliminating the need for centralized oracles.
To access historical data on Historeum, invoke precompiled contract 19 (0x13) with the account address, slot number, and past block number as parameters:
bytes memory args = abi.encodePacked(
address(this), // account
slotNumber, // slot number
blockNumber // block number
);
(
bool success, // status
bytes memory result // result (bytes)
) = address(0x13).staticcall(args);Alternatively, use the caerus keyword with our customized Solidity compiler:
bytes32 result = caerus(
address(this), // account
slotNumber, // slot number
blockNumber // block number
);