> ## Documentation Index
> Fetch the complete documentation index at: https://starkware-9575960b-starkzapv4.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# Choosing a privacy protocol
> Starkzap supports two independent privacy protocols—the STRK20 privacy pool and Tongo. Compare what each hides and pick the right one for your integration.
## Overview
Starkzap supports two privacy protocols. They are **independent implementations, not two backends behind one interface** — they have different state models, different proving setups, and different submission paths. You pick one per integration and code against it directly.
* **[STRK20 privacy pool](/build/starkzap/privacy/strk20)** — one pool for every token. Your balance is a set of private **notes**. A remote proving service builds a proof, and a relayer submits it, so your account never appears on-chain.
* **[Tongo](/build/starkzap/privacy/tongo)** — one contract per token. Your balance is a single **encrypted number** on your own account. Proofs are generated locally, and you submit the transaction yourself.
The names matter more than the words "privacy" and "confidential", which are near-synonyms in English but point at different protocols here. Say **STRK20** or **Tongo**.
## Comparison
| | STRK20 privacy pool | Tongo |
| - | - | - |
| **Hides** | Amounts, sender, and recipient | Amounts |
| **State model** | Private notes you spend | One encrypted balance per account |
| **Contracts** | One pool, all tokens | One contract per token |
| **Proving** | Remote proving service | Local, in your process |
| **Submission** | The paymaster's relayer — your account stays off-chain | Your own account |
| **Batching** | Never — the proof belongs to the transaction | Yes, through `wallet.tx()` |
| **You get back** | `send()` executes and returns a transaction hash | `Call[]` that you batch and send |
| **Keys** | Viewing key derived from your signing key | A separate Tongo private key you hold |
| **Wallets** | Private-key login only | Any wallet |
| **Install** | GitHub Packages, auth required, Node 24+ | npm, no auth |
| **Status** | Prerelease. Deposits need StarkWare access; the rest is self-hostable | Available |
## Which one to use
**Choose STRK20** when you need to hide *who* transacts, not just how much. Because a relayer submits the transaction, the sender's address, nonce, and gas payment stay off-chain. That is the property Tongo does not offer.
**Choose Tongo** when hiding amounts is enough, and you want an integration you can ship today: it installs from npm with no access request, works with any wallet, proves locally with no external service, and batches with your other calls in a single transaction.
Starkzap does not offer a shared abstraction over the two. Quoting the SDK itself: Tongo keeps an encrypted *balance* per account and proves locally, while the privacy pool spends *notes* and needs a remote prover whose output rides on the transaction rather than inside a call. There is no shared interface to code against.
## What neither protocol hides
Both protocols privatize what happens *between* entering and leaving. Entering and leaving are public in both.
Deposits and withdrawals are public. Withdrawing to the address you deposited from puts both ends of the pool on one address, which is enough to link them — so a fresh address is what preserves the gap.
Neither protocol hides that you interacted with it at all, and neither hides the timing or the token. Treat them as tools for unlinking a source from a destination, not as cloaks over your whole on-chain history.
## Next steps
Hide amounts, sender, and recipient. Notes, a remote prover, and relayer submission.
Hide amounts. Encrypted balances, local proving, batches with your other calls.
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