Rethinking Web3 Privacy: What You Can Actually Build with Sapphire

Most blockchains are designed to be public. Every transaction, every variable, every interaction—etched into global history. Great for transparency. Awful for anything involving sensitive logic, competitive behavior, or privacy-critical data.

But here’s the good news: we don’t have to accept “public-by-default” as a permanent constraint anymore.

With Sapphire, the EVM-compatible confidential paratime on Oasis, you can build apps that feel like Ethereum—but with built-in, hardware-backed privacy.

Let’s dig into what that actually means for developers.

🧠 Why Privacy Still Sucks in Web3

Web3 transparency is both its strength and its weakness. If you’re building anything like:

• An AI agent that trades or interacts with contracts.
• A prediction or betting app with sealed strategies.
• A game where moves and RNG matter.
• A DAO voting system where de-anonymization can influence votes.
• An enterprise integration that needs selective data disclosure.

You’re probably fighting your own stack.

Most L1s don’t support confidential logic without heavy zk engineering. Most rollups leak inputs in the mempool. Even commit-reveal is gameable if the reveal phase is delayed.

🔐 Enter Sapphire: A Confidential EVM Paratime on Oasis

Sapphire is not a new L1, and it's not a separate VM. It’s a confidential runtime (paratime) that supports Ethereum-style smart contracts but executes them inside a TEE (Trusted Execution Environment).

Key properties:

• 🛠️ Write contracts in Solidity.
• 🔐 Execute inside an enclave (Intel SGX).
• 🧾 Remote attestation ensures the node is running trusted code.
• 📦 randomBytes and other precompiles give you secure randomness, signing, and sealed state.
• 🔄 Same RPC interface—deploy via Hardhat, use ethers.js, etc.

It’s like deploying to Ethereum, but your state, inputs, and internal logic are confidential by default.

🧬 What Actually Happens Under the Hood?

Let’s walk through a typical tx lifecycle on Sapphire:

1. You call a contract using standard EVM tooling.

   result = PrivateGame.rollDice(playerId);

1. The tx routes to a Sapphire validator running a secure enclave.

• The contract bytecode + calldata are decrypted inside the enclave.
• The validator proves (via attestation) it’s running the unmodified Sapphire runtime.

1. Execution happens confidentially.

• All reads/writes use enclave-managed encryption keys.
• Storage is shielded from the host OS and network.
• Side channels and access patterns are obfuscated.

1. The result is signed and optionally exposed.

• Output can be returned publicly or privately (e.g. encrypted to the caller).
• Randomness or signing material can be securely injected via precompiles.

🎲 Secure Randomness via randomBytes()

One of the best parts of Sapphire is the native randomness precompile, which sidesteps every broken onchain RNG pattern:

bytes memory seed = Sapphire.randomBytes(32, "context");

Under the hood:

• Entropy is derived from per-epoch ephemeral keys inside the key manager paratime.
• Each block’s root RNG is constructed using KMAC256, TupleHash, cSHAKE.
• Merlin transcripts ensure per-transaction domain separation.
• All entropy remains inside the enclave—it never touches chain state.

If you’ve ever tried to implement a commit-reveal system and got front-run in the reveal window… this is your fix.

🛠️ What You Can Build

- AI Agents

Deploy bots that operate in real-time without leaking logic. Strategy models, LLM prompts, or reward functions stay sealed.

- DAO Voting

Implement confidential ballots with optional disclosure post-quorum. Voter patterns and influence trails are obfuscated.

- Games

Onchain card games, roguelikes, or puzzles where logic and state remain hidden from spectators.

- Encrypted Analytics

Process sensitive user inputs (e.g., health, finance, social data) inside smart contracts—without ever revealing them.

- Compliance-Friendly dApps

Let users selectively disclose encrypted state to auditors or regulators—without revealing it to the public.

- Tooling You’ll Actually Use

You don’t need to relearn everything. Sapphire supports:

• Standard Solidity syntax
• ethers.js, viem, etc.
• Deployment via Hardhat/Founrdy
• RPC-based reads/writes
• Full Oasis SDK if you want Rust runtime modules

For cross-chain or Ethereum compatibility, look into:

• 🌉 Oasis Privacy Layer: Use Sapphire as a privacy extension to existing chains.

🧪 Example: Private Key Gen in Solidity

Need a key pair for internal signing that no one can inspect?

(bytes memory pubkey, bytes memory privkey) = 
    Sapphire.generateSigningKeyPair(
        Sapphire.SigningAlg.Ed25519Pure,
        Sapphire.randomBytes(32, "keygen")
    );

That privkey stays encrypted within the enclave. No leakage, no backdoors, no recoverable state.

📚 Where to Start

🔍 Sapphire Dev Docs
🧪 ROFL Offchain Compute
💬 Join the Oasis Dev Discord

💬 Final Word

Confidential computation isn’t just about privacy. It’s about control, strategy, and secure design. If you’re still deploying apps where every tx is a public broadcast, you're building in a sandbox full of leaks.

Sapphire gives you the building blocks to fix that—without leaving EVM, without new syntax, and without trusting opaque bridges or oracles.

It’s not a replacement for Ethereum. It’s what Ethereum apps need when privacy isn’t optional.

Comments

[DC]

Great read. For a non-tech-savvy person like me, some of the content was like Greek but the need for privacy and the gist of what Sapphire is capable of was well put. What I like about Oasis is that they are not just talking about tech, but also showing the way with implementation that future developers can build on. WT3, as an autonomous, verifiable AI agent, and BlockVote, as a dApp for confidential voting, come to mind. For those who like to tinker around, the Oasis playground has a wide collection of demo dApps, and for those who like seeing the open source itself, GitHub is the place to explore.