Merkle Patricia Trie witness generator

This project aims to prepare witness generator for Merkle Patricia Trie circuit which is part of zkevm-circuits.

It is based on geth. It takes eth_getProof output and it transforms it into the MPT circuit witness.

MPT circuit checks that the modification of the trie state happened correctly.

Let us assume there are two proofs (as returned by eth getProof):

• A proof that there exists value val1 at key key1 for address addr in the state trie with root root1.
• A proof that there exists value val2 at key key1 for address addr in the state trie with root root2.

The circuit checks the transition from val1 to val2 at key1 that led to the change of trie root from root1 to root2.

For this reason, there are two parallel proofs for each trie modification. There is S (as State) proof which presents the state of the trie before the modification. And there is C (as Change) proof which presents the state of the trie after modification.

An example of eth_getProof output is given below:

[248 81 128 128 128 160 32 34 39 131 73 65 47 37 211 142 206 231 172 16 11 203 33 107 30 7 213 226 2 174 55 216 4 117 220 10 186 68 128 128 128 128 128 128 128 160 55 235 85 86 230 197 53 159 28 141 120 87 82 57 4 132 185 12 24 158 142 210 106 188 12 87 179 231 52 16 126 229 128 128 128 128 128]
[226 160 59 138 106 70 105 186 37 13 38 205 122 69 158 202 157 33 95 131 7 227 58 235 229 3 121 188 90 54 23 236 52 68 1]

The first element of the proof is a branch containing two children. The second element of the proof is a storage leaf contained in the branch (from the first proof element).

To simplify the MPT circuit, the eth_getProof elements are not directly used as rows. Instead, the rows are prepared as:

[1 0 1 0 248 81 0 248 81 0 11 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]
[0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1]
[0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1]
[0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1]
[0 160 32 34 39 131 73 65 47 37 211 142 206 231 172 16 11 203 33 107 30 7 213 226 2 174 55 216 4 117 220 10 186 68 0 160 32 34 39 131 73 65 47 37 211 142 206 231 172 16 11 203 33 107 30 7 213 226 2 174 55 216 4 117 220 10 186 68 1]
[0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1]
[0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1]
[0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1]
[0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1]
[0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1]
[0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1]
[0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1]
[0 160 55 235 85 86 230 197 53 159 28 141 120 87 82 57 4 132 185 12 24 158 142 210 106 188 12 87 179 231 52 16 126 229 0 160 88 197 127 237 244 146 28 57 104 36 96 69 159 84 254 170 28 196 41 183 253 107 213 32 170 141 111 191 30 100 117 55 1]
[0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1]
[0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1]
[0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1]
[0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 128 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1]
[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 16]
[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 17]
[226 160 59 138 106 70 105 186 37 13 38 205 122 69 158 202 157 33 95 131 7 227 58 235 229 3 121 188 90 54 23 236 52 68 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2]
[1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 13]
[226 160 59 138 106 70 105 186 37 13 38 205 122 69 158 202 157 33 95 131 7 227 58 235 229 3 121 188 90 54 23 236 52 68 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3]
[17 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 14]
[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 15]
[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 19]

...

Generate witnesses

To generate witnesses for MPT circuit, execute

go test -v ./...

To generate the tests that use a local blockchain you need a local geth. You would need to run something like:

geth --dev --http --ipcpath ~/Library/Ethereum/geth.ipc

The local geth is used to generate some tests that have a small number of accounts so that these accounts appear in the first or second level of the trie. You might need to remove the database if you already have some accounts:

geth removedb

The witness files will appear in generated_witnesses folder.

Format the code

To format the code use:

gofmt -w ./*

Calling from Rust

Build:

go build -buildmode=c-archive -o libmpt.a witness_gen_wrapper.go 

Copy libmpt.a and libmpt.h to rust_call/build:

mv libmpt.* rust_call/build

Note: to avoid the problem described , the following has been set in rust_call/.cargo/config:

[build]
rustflags = ["-C", "link-args=-framework CoreFoundation -framework Security"]