Compatibility with the Ethereum Virtual Machine (EVM)

The Aurora Engine implements an Ethereum Virtual Machine (EVM) on top of the NEAR Protocol.

Balances

EVM address balances are denominated in ether (ETH) for compatibility with Ethereum.

Gas

See notes on gas.

Precompiles

Standard precompiles

Address	ID	Name	Spec	Status
0x01	ECRecover	ECDSA public key recovery	Yellow Paper	✅
0x02	SHA256	SHA-2 256-bit hash function	Yellow Paper	✅
0x03	RIPEMD160	RIPEMD 160-bit hash function	Yellow Paper	✅
0x04	Identity	Identity function	Yellow Paper	✅
0x05	ModExp	Big integer modular exponentiation	EIP-198	✅
0x06	BN128Add	Elliptic curve addition	EIP-196	✅
0x07	BN128Mul	Elliptic curve scalar multiplication	EIP-196	✅
0x08	BN128Pair	Elliptic curve pairing check	EIP-197	✅
0x09	Blake2F	BLAKE2b F compression function	EIP-152	✅

Opcodes

BLOCKHASH

This opcode currently does not return a real blockhash. However, it does respect the logic that a non-zero value is returned for the most recent 256 blocks (not including the current block). For all other inputs it returns zero. The non-zero value that is returned is computed based on the block height and properties of the Aurora Engine contract (chain ID and account ID). Concretely, as of #213, the value returned is

BLOCKHASH(h: u64) = sha256( 0x00 || h || chain_id || account_id )

where || is byte concatenation and it is assumed h (a 64-bit number) is converted to bytes in big endian encoding. The leading zero byte in the concatenation is a version byte which may change if a new blockhash scheme is introduced in the future. The chain_id depends on the network the Aurora Engine contract is deployed to (see networks table). The account_id is the name of the NEAR account where the contract is deployed (see the Engine ID column in the networks table).

COINBASE

This opcode returns the EVM address of the Aurora Engine.

For example, for the Aurora Engine deployment on the aurora account, COINBASE returns 0x4444588443C3a91288c5002483449Aba1054192b.

DIFFICULTY

This opcode always returns zero, since NEAR is not a proof-of-work (PoW) network.

GASLIMIT

This opcode always returns 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff (2^256-1).

Limitations

• The Berlin hard fork is not yet supported. The EVM currently supports the feature set of the Istanbul hard fork.

• The BLOCKHASH opcode does not return the hash of an actual block (see above for details).

Source Code

The Aurora Engine source code repository is at: github.com/aurora-is-near/aurora-engine.