EVM Compatibility

The eSpace implements an Ethereum Virtual Machine (EVM) with alignment to Ethereum's behavior through CIP-645. Below are some differences between eSpace and Ethereum:

Transaction Type

eSpace initially only supports 155 type transaction (legacy transactions)
EIP-2930 (type 1) & EIP-1559 (type 2) transactions are supported after hardfork v2.4.0.
EIP-4844 (type 3) transactions are not supported.
EIP-7702 (type 4) transactions are supported after hardfork v3.0.0.

EVM Opcodes

As of hardfork v3.0.0 (CIP-645), Conflux eSpace implements multiple Ethereum Improvement Proposals (EIPs) to align behavior with Ethereum's EVM:

Opcode-Specific Changes

BLOBHASH and BLOBBASEFEE opcodes (EIP-4844) are implemented with consistent "zero" results

Block Time

The NUMBER opcode will return the tree-graph epoch number. As a result, block.number used in eSpace contracts will not grow at a stable and predictable rate, and so it might not be suitable for measuring time.

Block generate rate is 1.25s per block (mainnet), is same as Core Space Epoch time.

Contract Size

Contract max code size is 49152 (double as Ethereum).

Transaction Fees

Due to Conflux's storage collateral mechanism and high-performance design, storage-related operations have adjusted gas costs (doubled from Ethereum's values):

SSTORE: 40000 gas (instead of 20000 gas in Ethereum) when changing a storage entry from zero to non-zero
Contract deployment: Each byte costs 400 gas (instead of 200 gas in Ethereum)
EIP-7702 PER_EMPTY_ACCOUNT_COUNT: 50000 gas (instead of 25000 gas in Ethereum)

Gas Refunds

Gas refund cap: In Ethereum, if a transaction's gas limit exceeds the actual gas cost, the remaining gas is fully refunded. In contrast, Conflux refunds a maximum of 1/4 of the gas limit. Check Gas Limit, Gas Used, and Gas Charged for more details.
EIP-7702 refund difference: When updating delegate addresses (rather than creating a new delegation), Conflux does not issue the 12500 gas refund that Ethereum provides.

BLOCKHASH Gas Pricing

Conflux supports querying a larger range of blocks [n-65535, n] compared to Ethereum's [n-256, n-1]. Corresponding gas prices for BLOCKHASH are adjusted as follows:

Ethereum: 20 gas (uniform for all cases)
Conflux: 2100 gas (for the range [n-65535, n-257]), 100 gas (for blocks in [n-256, n-1])

Transaction Gas limit

Only blocks whose height is a multiple of 5 can include Ethereum-type transactions. The total gas limit of these transactions cannot exceed half of the block gas limit, which is 30 million gas.
A transaction's gas limit should be no less than 100 times the byte size of its call data. Check CIP-130 for more details.

COINBASE Address Handling

The COINBASE opcode returns a hex20 address corresponding to Core Space rather than eSpace. The eSpace address with the same hex20 value is not considered "warm" per EIP-2929.

Transaction Balance Handling

When transaction balance cannot afford maximum cost (max gas price × gas limit + tx value):

Ethereum: Transaction fails without nonce increment or fee deduction
Conflux: Nonce is incremented and maximum effective gas price × gas limit is deducted (or entire balance if insufficient)

The maximum effective gas price equals to gasPrice if gasPrice is specified otherwise min(maxFeePerGas, baseFeePerGas+maxPriorityFeePerGas).

EVM Precompiles

All standard precompiles are supported.

Address	ID	Name	Spec	Status	Version
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	✅
0x0a	`PointEvaluation`	Verify p(z) = y given commitment that corresponds to the polynomial p(x) and a KZG proof	EIP-4844	✅	V2.4.0
0x0b	`BLS12_G1ADD`	BLS12-381 G1 addition	EIP-2537	✅	V3.0.0
0x0c	`BLS12_G1MSM`	BLS12-381 G1 multi-scalar multiplication	EIP-2537	✅	V3.0.0
0x0d	`BLS12_G2ADD`	BLS12-381 G2 addition	EIP-2537	✅	V3.0.0
0x0e	`BLS12_G2MSM`	BLS12-381 G2 multi-scalar multiplication	EIP-2537	✅	V3.0.0
0x0f	`BLS12_PAIRING_CHECK`	BLS12-381 pairing check	EIP-2537	✅	V3.0.0
0x10	`BLS12_MAP_FP_TO_G1`	BLS12-381 map FP to G1	EIP-2537	✅	V3.0.0
0x11	`BLS12_MAP_FP2_TO_G2`	BLS12-381 map FP2 to G2	EIP-2537	✅	V3.0.0

Phantom transactions

A cross-space transaction is a transaction in the Conflux core space that, at some point during its execution, calls one of the state-changing (i.e., not view) methods of the CrossSpaceCall internal contract. Such transactions can change CFX balances and contract storage in both spaces, core and eSpace.

As EVM clients are not aware of Conflux space transactions (the two spaces use different transaction formats), we construct one or more phantom transactions (aka virtual transactions) for each call to the CrossSpaceCall internal contract. These phantom transactions are derived from the corresponding core space transaction, they do not exist in the ledger. Phantom transactions have the following special properties:

gas and gasPrice are 0. Gas for cross-space transactions is charged in the core space. Therefore, the corresponding phantom transactions do not consume any gas.
Invalid signature (r, s, v, standardV). The Conflux protocol is unable to sign transactions on behalf of the sender of the cross-space transaction. Therefore, phantom transactions use a fake signature that will not pass ECDSA verification.

Example

When we retrieve epoch 0x72819 in the Conflux core space, we see it contains a single Conflux transaction.

cfx_getBlockByEpochNumber(0x72819, true)

{
  "epochNumber": "0x72819",
  "hash": "0x7440c9e8ebb2e87a7d187e4ad6d09027d860b3948cf4364bb883c028b6c3a858",
  "transactions": [
    {
      "hash": "0xe89ef4b61434ec331b621b8687033f9e4058e76759a3522bdc50e0cb358f505e",
      "blockHash": "0x7440c9e8ebb2e87a7d187e4ad6d09027d860b3948cf4364bb883c028b6c3a858",
      "from": "NET8888:TYPE.USER:AAJFT5SK5RGK2KTJPMPUEJ69989N15KCCY7JAJEUP2",
      "to": "NET8888:TYPE.CONTRACT:ACAP3N9KXZ7C4TU5NUU8G65FJ7A09MG1FY77ZAYSVW",
      "gasPrice": "0x1",
      "gas": "0x8b28d",
      "storageLimit": "0x54",
      "r": "0x2b943e84111cd5f95fbdf15667329ac546c9e5b99548d3c3702aeced4f07de6d",
      "s": "0x2f47ae3c15ec2d1cbcf5bde3870aa21e1df54e8b7b926840a54faa9951cb3321",
      "v": "0x0",
      ...
    }
  ],
  ...
}

When we retrieve the corresponding block in the eSpace, we see it contains two phantom transactions.

eth_getBlockByNumber(0x72819, true)

{
  "hash": "0x7440c9e8ebb2e87a7d187e4ad6d09027d860b3948cf4364bb883c028b6c3a858",
  "number": "0x72819",
  "transactions": [
    {
      "hash": "0xfcdcf304b6b9dc263625b0924efaf3a7eb7044a17d27c0b8d631025b55d1147e",
      "blockHash": "0x7440c9e8ebb2e87a7d187e4ad6d09027d860b3948cf4364bb883c028b6c3a858",
      "from": "0x0000000000000000000000000000000000000000",
      "to": "0xf709629eee416c2d2a53692d38f1568538d8022f",
      "gasPrice": "0x0",
      "gas": "0x0",
      "r": "0x1",
      "s": "0x1",
      "v": "0x4593",
      ...
    },
    {
      "hash": "0xca2f5c5848458bea556f99e626db7108377d600e24add1920c4106358a1a5502",
      "blockHash": "0x7440c9e8ebb2e87a7d187e4ad6d09027d860b3948cf4364bb883c028b6c3a858",
      "from": "0xf709629eee416c2d2a53692d38f1568538d8022f",
      "to": "0xdacf3af269b55ece5fe3239626a27f2a76c48245",
      "gasPrice": "0x0",
      "gas": "0x0",
      "r": "0x1",
      "s": "0x1",
      "v": "0x4593",
      ...
    }
  ],
  ...
}

Transaction Type​

EVM Opcodes​

Opcode-Specific Changes​

Block Time​

Contract Size​

Transaction Fees​

Storage-Related Gas Costs​

Gas Refunds​

BLOCKHASH Gas Pricing​

Transaction Gas limit​

COINBASE Address Handling​

Transaction Balance Handling​

EVM Precompiles​

Phantom transactions​

Example​

Resources​