Merkle opening constant circuit description (#123) (#124)

PLONK requires the circuit description + witness indexes to be constant
so the same verifier data can be reused to check different proofs.

The previous implementation contained an optimization that swaps the
witness index to reduce the number of gates.

This optimization may lead to inconsistencies when reusing verifier keys
because the verification will depend on the disposition of the witness
data, and this is undesirable.

Resolves #122

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.20.0] - 2021-04-06
+
 ### Changed
 
 - Update `dusk-plonk` from `0.6` to `0.7` #119

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "dusk-poseidon"
-version = "0.20.0-pre.1"
+version = "0.20.0"
 authors = [
   "zer0 <[email protected]>", "vlopes11 <[email protected]>", "CPerezz <[email protected]>", "Kristoffer Ström <[email protected]>"
 ]
@@ -15,13 +15,13 @@ repository = "https://github.com/dusk-network/poseidon252"
 dusk-bls12_381 = {version = "0.6", default-features = false}
 dusk-jubjub = {version = "0.8", default-features = false}
 dusk-bytes = "0.1"
-dusk-hades = { version = "0.15.0-pre", default-features = false }
+dusk-hades = { version = "0.15", default-features = false }
 canonical = {version = "0.5", optional = true}
 canonical_derive = {version = "0.5", optional = true}
 microkelvin = {version = "0.6", optional = true}
 nstack = {version = "0.7", optional = true}
 
-dusk-plonk = {version="0.7.0-pre", default-features = false, optional = true}
+dusk-plonk = {version="0.7", default-features = false, optional = true}
 anyhow = { version = "1.0", optional = true }
 thiserror = { version = "1.0", optional = true }
 

src/tree/zk.rs

@@ -89,7 +89,7 @@ mod tests {
     use crate::tree::{self, PoseidonAnnotation, PoseidonBranch, PoseidonTree};
     use canonical_host::MemStore;
     use dusk_plonk::circuit;
-    use dusk_plonk::prelude::Error as PlonkError;
+    use dusk_plonk::error::Error as PlonkError;
     use dusk_plonk::prelude::*;
     use rand::rngs::StdRng;
     use rand::SeedableRng;