Differences from Ethereum

Overview

The Seismic EVM is approximately a superset of the EVM

What's the same

• Transaction construction and serialization identical to Ethereum (with one new transaction type)

• Address generation, gas estimation, and signing work the same as Ethereum

• Almost all RPC methods are identical to reth

• Standard Solidity bytecode will behave identically on Seismic

• Seismic supports all of Ethereum's opcodes & precompiles

• Transaction priority & fees follow EIP-1559 rules

• Seismic will produce empty blocks when there are no pending transactions

Key differences

• Shielded storage: Solidity contracts can store private data on-chain

• Runs in a TEE: Seismic nodes must run in Trusted Execution Environments

• Seismic transaction: We added a new transaction type that allows you to encrypt your calldata

EVM Compatibility

Opcodes

• CLOAD – load shielded data from storage

• CSTORE – write shielded data to storage

• TIMESTAMP_MS – get the block timestamp in milliseconds

Seismic transaction

The transaction with type 0x4a allows users to encrypt their calldata. These otherwise work just like legacy transactions. We also support the other standard Ethereum transaction types (Legacy, EIP-1559, EIP-2930, EIP-4844, EIP-7702)

Precompiles

All standard Ethereum precompiles are still available. Seismic added 6 new precompiles to our EVM:

• RNG: 0x64 securely generate a random number

• ECDH 0x65: Elliptic Curve Diffie-Hellman, for generating a shared secret given a public key and secret key

• AES-GCM cryptography

  • Encryption 0x66

  • Decryption 0x67

• HKDF 0x68: generate a cryptographic keys from a parent key

• Secp256k1 0x69: Sign a message given a secret key

Staking

Seismic uses the same staking contract as Ethereum, which is hardcoded into our Genesis block at address 0x00000000219ab540356cbb839cbe05303d7705fa

Block times

We will often produce multiple blocks in the same second, yet Ethereum's block timestamps are expressed in terms of unix seconds. Our solution to this:

• Block headers and the EVM see timestamps in milliseconds

• All RPC endpoints will format block timestamps in seconds for Ethereum compatibility (not ms)

• In Seismic Solidity, block.timestamp returns unix seconds, just like in standard solidity. We added block.timestamp_ms which returns unix milliseconds

RPC compatibility

We support almost every RPC endpoint in Reth, and have added a few more of our own

These methods are in Reth, but will behave differently on Seismic:

• Calls to tracing endpoints will remove shielded data from the trace

• Calls to getStorageAt will fail if the requested storage slot holds shielded data