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README.md

@@ -1,3 +1,16 @@
 # `lib-keccak`
 
-wtf is even that
+Implementation of the `Keccak-f[1600]` permutation in Solidity.
+
+## Examples
+
+**Differential test vs. `tiny-keccak`**
+
+```sh
+just rust-fuzz
+```
+
+**Run contract tests**
+```sh
+just sol-test
+```

contracts/lib/LibKeccak.sol

@@ -49,11 +49,12 @@ library LibKeccak {
 
             // xor five elements of the state matrix and store the result in `out`
             function xorFive(ptr, a, b, c, d, e) -> out {
-                out :=
-                    xor(
-                        stateElem(ptr, a),
-                        xor(xor(stateElem(ptr, b), stateElem(ptr, c)), xor(stateElem(ptr, d), stateElem(ptr, e)))
-                    )
+                a := stateElem(ptr, a)
+                b := stateElem(ptr, b)
+                c := stateElem(ptr, c)
+                d := stateElem(ptr, d)
+                e := stateElem(ptr, e)
+                out := xor(a, xor(xor(b, c), xor(d, e)))
             }
 
             // Performs an indivudual rho + pi computation, to be used in the full `thetaRhoPi` chain.
@@ -182,7 +183,7 @@ library LibKeccak {
 
             // set a state element in the passed `StateMatrix` struct memory ptr.
             function setStateElem(ptr, idx, data) {
-                mstore(add(ptr, shl(0x05, idx)), and(data, 0xFFFFFFFFFFFFFFFF))
+                mstore(add(ptr, shl(0x05, idx)), and(data, U64_MASK))
             }
 
             // fetch a state element from the passed `StateMatrix` struct memory ptr.

justfile

@@ -8,15 +8,15 @@ testdata:
   echo $(cat out/StatefulSponge.sol/StatefulSponge.json | jq -r '.deployedBytecode.object' | cut -c3-) > testdata/stateful_sponge
 
 # lint the Rust code
-rust-lint:
+rust-lint: testdata
   cargo +nightly fmt -- && cargo +nightly clippy --all --all-features -- -D warnings
 
 # build the fuzzing tool binary
-rust-build:
+rust-build: testdata
   cargo build --release
 
 # run the fuzzing tool
-rust-fuzz:
+rust-fuzz: testdata
   cargo run --release
 
 # run the solidity tests