Building a Cross-Chain Confidential "Trust Score Oracle" with Oasis Sapphire + OPL + ROFL

This tutorial shows how to add privacy + verifiable off-chain compute to any EVM dApp by combining: Sapphire: Oasis’ confidential EVM (encrypted calldata + confidential contract state). OPL (Oasis Privacy Layer): message bridge pattern to “bolt privacy onto” existing EVM apps by offloading sensitive logic to Sapphire. ROFL (Runtime Off-Chain Logic): a TEE-managed app runtime (containers or single binaries) with secrets stored via built-in KMS and on-chain management through Sapphire. Real use case You run a lending/access-control dApp on a Home chain (Ethereum/L2). You want a wallet "Trust Score" derived from sensitive signals: private allowlists (KYC provider, internal risk flags), off-chain identity reputation (GitHub activity, paid subscription, enterprise customer), model inference results (fraud classifier). You don’t want to leak: raw signals, model features, user identity mappings, or scoring logic. Design goal: Home chain contract gets a public, verifiable decision (e.g., score