1. 引言
EVM Proof用于证明：
- state trie root的变化是正确的，通过验证一个区块内所包含的交易都具有正确的执行结果。
EVM circuit会重新实现EVM，但是是以验证的角度来验证，即意味着，Prover可帮助提供线索，只要这些线索不会与结果相矛盾。如，Prover可提供关于某call是否将revert的线索，或者某opcode是否将遇到错误的线索，然后该EVM circuit可验证执行结果是正确的。
在区块内包含的交易可以是简单的ether transfers、contraction creation或 contract interactions，因为每笔交易具有可变的execution trace，无法使用固定的circuit layout来验证特定region的特定logic，为此，我们需要a chip来验证所有可能的logics，该chip将自身重复来实现整个circuit。
2. 定制类型
为线索定制了如下类型：
| Name | Type | Description |
|---|---|---|
GlobalCounter |
int |
Order of random access to BusMapping, which should be in sequence |
BusMapping |
List[Tuple[int, ...]] |
List of random read-write access data in sequence with GlobalCounter as index |
3. Random Accessible Data
EVM解析器可做any random access to data类似如account balance、account storage、stack in current scope、memeory in current scope，但是对于EVM circuit来说，其很难跟踪这些数据来保证这些数据的实时一致性。
因此，EVM proof具有State proof来提供a valid list of random read-write access records indexed by the GlobalCounter as a lookup table to do random access at any moment。
将random read-write access records list称为BusMapping，因为其作用类似于电脑中的bus，用于在不同部件之间传输数据。类似的，read-only数据以random access方式从lookup table加载。
| Target | Index | Accessible By | Description |
|---|---|---|---|
Block |
{enum} |
Read |
Block constant decided before executing the block |
BlockHash |
{index} |
Read |
Previous 256 block hashes as a encoded word array |
AccountNonce |
{address} |
Read, Write |
Account’s nonce |
AccountBalance |
{address} |
Read, Write |
Account’s balance |
AccountCodeHash |
{address} |
Read, Write |
Account’s code hash |
AccountStorage |
{address}.{key} |
Read, Write |
Account’s storage as a key-value mapping |
Code |
{hash}.{index} |
Read |
Executed code as a byte array |
Call |
{id}.{enum} |
Read |
Call’s context decided by caller (includes EOA and internal calls) |
CallCalldata |
{id}.{index} |
Read |
Call’s calldata as a byte array (only for EOA calls) |
CallSignature |
{id}.{index} |
Read |
Call’s signature as a byte array (only for EOA calls) |
CallState |
{id}.{enum} |
Read, Write |
Call’s internal state |
CallStateStack |
{id}.{index} |
Read, Write |
Call’s stack as a encoded word array |
CallStateMemory |
{id}.{index} |
Read, Write |
Call’s memory as a byte array |
3. Circuit Constraints
该重复chip具有2个main states，一个调用初始化，另一个用于bytecode execution。
参考资料
[1] EVM Proof