Prava X

Prava X is a privacy-first cross-chain intents product on Polkadot Hub.

Under the hood, it uses a dual-VM design:

• Solidity handles intent creation, settlement, staking, and escrow
• Rust PolkaVM handles private intent verification

The goal is simple: let users express intents without exposing trade parameters up front.

Demo Video

Watch the product walkthrough here: YouTube Demo

What It Does

• Public intents can be signed off-chain with EIP-712
• Private intents store only a commitment on-chain
• Solvers fill intents and provide buy-side liquidity
• Rust PolkaVM verifies private reveals against the original commitment
• Cross-chain fills can use escrow plus the XCM precompile

Core Components

• src/IntentReactor.sol Core contract for intent lifecycle, fills, and privacy verification flow
• src/SolverRegistry.sol Native PAS staking, activation, unstaking, and slashing hooks
• src/EscrowVault.sol Escrow used for cross-chain settlement flows
• rust-privacy-engine/src/rust-privacy-engine.rs Rust PolkaVM contract for commitment computation and verification
• solver/ Off-chain solver service
• frontend/ Next.js app for creating and filling intents

Deployed Addresses

Current Polkadot Hub TestNet addresses used by the frontend:

Component	Address	Explorer
Privacy Engine	0x3121f213e88cf5b2b02e330c98a92a19ee81a3d6	View
Intent Reactor	0x02da54F6Af05423D3441166FDf4c779BD5911E7c	View
Escrow Vault	0xA4093fDcfFe5e37554B55840aB77EC6f23CEFc8F	View
Solver Registry	0x5db591fad47489c144737209969c6F055869F5C1	View
Mock USDC	0xFAD89510E5D1c3624C05053c1752B06a2D255387	View
Mock DOT	0x8D6350aDC02B2D9c181D6b475439A14B6067eA83	View
Solver Wallet	0x271ADdfC96533Ec92C0Eb905eAAab6f68040db06	View

High-Level Flow

Maker creates an intent
  -> Public: sign off-chain
  -> Private: sign, then submit commitment on-chain
Solver fills the intent
  -> Private fills call Rust PolkaVM for verification
Settlement completes on Solidity
  -> XCM path uses escrow + precompile

Local Development

Requirements

• Foundry
• Rust
• Node.js

Build Contracts

forge build
cd rust-privacy-engine && cargo build --release

Deploy

export ETH_RPC_URL="https://services.polkadothub-rpc.com/testnet"

PRIVACY_ENGINE=$(cast send --account dev --create \
  "$(xxd -p -c 99999 rust-privacy-engine/target/rust-privacy-engine.release.polkavm)" \
  --json | jq -r .contractAddress)

PRIVACY_ENGINE_ADDRESS=$PRIVACY_ENGINE forge script script/Deploy.s.sol \
  --rpc-url $ETH_RPC_URL --broadcast

Run Frontend

cd frontend
npm install
npm run dev

Run Solver

cd solver
npm install
npm run dev

Network

• Polkadot Hub TestNet
• RPC: https://services.polkadothub-rpc.com/testnet
• Chain ID: 420420417

Repo Layout

src/                  Solidity contracts
rust-privacy-engine/  Rust PolkaVM verifier
frontend/             Web app
solver/               Off-chain solver
script/               Deployment scripts
docs/                 Supporting docs

License

MIT