EIP-1014 adds the CREATE2 opcode, which creates contracts at deterministic addresses derived from the sender, a salt, and the initcode hash.
It enables counterfactual deployments, factory patterns, and state-channel workflows where addresses are known ahead of time.
Adds a new opcode (CREATE2) at 0xf5, which takes 4 stack arguments: endowment, memory_start, memory_length, salt. Behaves identically to CREATE (0xf0), except using keccak256( 0xff ++ address ++ salt ++ keccak256(init_code))[12:] instead of the usual sender-and-nonce-hash as the address where the contract is initialized at.
The CREATE2 has the same gas schema as CREATE, but also an extra hashcost of GSHA3WORD * ceil(len(init_code) / 32), to account for the hashing that must be performed. The hashcost is deducted at the same time as memory-expansion gas and CreateGas is deducted: before evaluation of the resulting address and the execution of init_code.
0xff is a single byte,address is always 20 bytes,salt is always 32 bytes (a stack item).The preimage for the final hashing round is thus always exactly 85 bytes long.
The coredev-call at 2018-08-10 decided to use the formula above.
Allows interactions to (actually or counterfactually in channels) be made with addresses that do not exist yet on-chain but can be relied on to only possibly eventually contain code that has been created by a particular piece of init code. Important for state-channel use cases that involve counterfactual interactions with contracts.
keccak256(rlp([sender, nonce])) formula, as 0xff can only be a starting byte for RLP for data many petabytes long.Since address calculation depends on hashing the init_code, it would leave clients open to DoS attacks if executions could repeatedly cause hashing of large pieces of init_code, since expansion of memory is paid for only once. This EIP uses the same cost-per-word as the SHA3 opcode.
The init_code is the code that, when executed, produces the runtime bytecode that will be placed into the state, and which typically is used by high level languages to implement a 'constructor'.
This EIP makes collisions possible. The behaviour at collisions is specified by EIP-684:
If a contract creation is attempted, due to either a creation transaction or the
CREATE(or futureCREATE2) opcode, and the destination address already has either nonzero nonce, or nonempty code, then the creation throws immediately, with exactly the same behavior as would arise if the first byte in the init code were an invalid opcode. This applies retroactively starting from genesis.
Specifically, if nonce or code is nonzero, then the create-operation fails.
With EIP-161
Account creation transactions and the
CREATEoperation SHALL, prior to the execution of the initialisation code, increment the nonce over and above its normal starting value by one
This means that if a contract is created in a transaction, the nonce is immediately non-zero, with the side-effect that a collision within the same transaction will always fail -- even if it's carried out from the init_code itself.
It should also be noted that SELFDESTRUCT (0xff) has no immediate effect on nonce or code, thus a contract cannot be destroyed and recreated within one transaction.
Example 0
0x00000000000000000000000000000000000000000x00000000000000000000000000000000000000000000000000000000000000000x00320060x4D1A2e2bB4F88F0250f26Ffff098B0b30B26BF38Example 1
0xdeadbeef000000000000000000000000000000000x00000000000000000000000000000000000000000000000000000000000000000x00320060xB928f69Bb1D91Cd65274e3c79d8986362984fDA3Example 2
0xdeadbeef000000000000000000000000000000000x000000000000000000000000feed0000000000000000000000000000000000000x00320060xD04116cDd17beBE565EB2422F2497E06cC1C9833Example 3
0x00000000000000000000000000000000000000000x00000000000000000000000000000000000000000000000000000000000000000xdeadbeef320060x70f2b2914A2a4b783FaEFb75f459A580616Fcb5eExample 4
0x00000000000000000000000000000000deadbeef0x00000000000000000000000000000000000000000000000000000000cafebabe0xdeadbeef320060x60f3f640a8508fC6a86d45DF051962668E1e8AC7Example 5
0x00000000000000000000000000000000deadbeef0x00000000000000000000000000000000000000000000000000000000cafebabe0xdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef320120x1d8bfDC5D46DC4f61D6b6115972536eBE6A8854CExample 6
0x00000000000000000000000000000000000000000x00000000000000000000000000000000000000000000000000000000000000000x320000xE33C0C7F7df4809055C3ebA6c09CFe4BaF1BD9e0