User Guide
Complete Guide to Private Transactions
For Businesses & Individuals
Learn how to protect your financial privacy on Solana. Step-by-step tutorials, real examples, and best practices.
What is Sentinel?
Sentinel is a privacy application built on Solana that allows you to send and receive funds without revealing amounts or identities to the public.
It is built for institutional-grade operations: controlled access, cryptographic integrity, and selective disclosure workflows for compliance teams.
Unlike regular Solana transactions where everything is visible on-chain, Sentinel uses encrypted vaults and Zero-Knowledge proofs to keep your financial activity private.
Amounts and recipients are encrypted. Only you can see your vault balance and transaction history.
Built on Solana. Transactions complete in 1-2 seconds for $0.01-0.05 in fees.
Zero-Knowledge cryptography ensures privacy without compromising security or verifiability.
Not a mixer. Individual vaults allow for selective disclosure and audit trails when needed.
| Feature | Regular Solana | Sentinel |
|---|---|---|
| Transaction amount | Public ❌ | Private ✓ |
| Recipient address | Public ❌ | Private ✓ |
| Wallet balance | Public ❌ | Private ✓ |
| Transaction speed | 1-2 seconds ✓ | 1-2 seconds ✓ |
| Transaction cost | $0.01 ✓ | $0.01-0.05 ✓ |
| Self-custody | Yes ✓ | Yes ✓ |
How It Works
Privacy Flow
Public
✓ Balance encrypted
✓ Transfers private
✓ Only you can view
Private
Public
Deposit & withdraw visible · Everything inside the vault is private
Your vault is like an encrypted safe on the blockchain. When you deposit funds, they enter the vault. All transfers between vaults are private. When you withdraw, funds leave the vault.
Your balance is stored as a 64-byte encrypted ciphertext using ElGamal encryption. Only your private key can decrypt it.
No password recovery, no "forgot password". If you lose your wallet's seed phrase, you lose access to your vault forever.
Deposits/withdrawals use Zero-Knowledge proofs to verify amounts are correct without revealing the actual values.
Sentinel operators cannot see balances, freeze funds, or block transactions. It's a smart contract — code, not people.
Important: The initial deposit and final withdrawal are visible on-chain (like any Solana transaction). Everything that happens INSIDE your vault is private.
Getting Started
Connect your wallet
Open Sentinel and connect your Solana wallet (Phantom, Solflare, etc.). Make sure you're on the correct network (mainnet or devnet).
Create your vault
Click "Create Vault" to initialize your encrypted vault. This creates your ZK vault account and prepares per-asset vault state for SOL and supported SPL assets. This is a one-time setup.
Deposit funds
Transfer SOL or USDC from your wallet into your Sentinel vault. Each asset is tracked in dedicated vault state so deposits and withdrawals stay coherent across multi-asset usage. This transaction is visible on-chain.
Use private transfers
Now you can send funds to other Sentinel vaults privately. The recipient's vault address, amount, and your balance remain encrypted. To receive a confidential transfer without having deposited first, use Prepare to receive in the Setup section (this calls prepare_receive_sol so your vault is ready for incoming SOL).
Withdraw when needed
Withdraw funds from your vault back to your regular wallet anytime. This transaction is visible on-chain.
Reading Your Vault Balance
Your vault balance is encrypted on-chain. Only you can decrypt it with your wallet. The interface reads the encrypted state by asset, then decrypts locally.
Click "View Balance"
In the Sentinel app, click the "View Balance" button in your vault dashboard. This queries your encrypted vault data from the blockchain using the get_balance instruction.
Wallet decrypts locally
Your browser uses your wallet's private key to decrypt the balance. This happens entirely in your browser — no data is sent to any server.
Balance displays
You see your decrypted balance. No one else can see this — not even Sentinel operators. The encrypted data remains on-chain, but only you can read it.
Privacy Note: If someone has access to your unlocked wallet, they can decrypt your vault balance. Always lock your wallet when not in use.
Who Uses Sentinel?
Sentinel is used by businesses, traders, institutions and individuals who need financial privacy. Here are concrete examples:
Business Owner — Import/Export
Sophie, 42 · Textile SME · $5M revenue
Use case
Sophie buys textiles from China and pays in USDC. She uses Sentinel to prevent competitors from analyzing her blockchain transactions and identifying her suppliers.
How they use it
- Deposits $200k in her Sentinel vault monthly
- Pays each supplier privately from vault to vault
- Competitors cannot see amounts or recipients
- Maintains competitive advantage on supply chain
Result
Supply chain protected · Better negotiation · Instant payments · 90% lower fees vs SWIFT
Investment Fund — Venture Capital
Marc, 38 · Crypto fund · $50M AUM
Use case
Marc invests in early-stage tokens. Without Sentinel, other funds see his purchases on-chain and copy his positions, driving up prices before he's done accumulating.
How they use it
- Deposits fund capital in Sentinel vaults
- Buys tokens through private vault transfers
- No one can see which tokens or amounts
- Builds positions without being front-run
- Provides ZK solvency proofs to LPs for audits
Result
Alpha preserved · No front-running · +15-20% better performance · Compliance maintained
Bank — Cross-Border Payments
Innovation Director · Regional bank · 2000 B2B clients
Use case
The bank wants to offer instant, cheap payments to Asia for business clients. But public Solana transactions would violate banking secrecy and expose client financial strategies.
How they use it
- Creates institutional Sentinel vault with $10M liquidity
- Each business client gets a sub-vault
- International payments go vault-to-vault (private)
- Amounts and recipients remain confidential
- Can produce compliance reports without public exposure
Result
Banking secrecy preserved · Instant settlement · 90% cost reduction · Competitive edge
Trader — International Arbitrage
Karim, 29 · Independent trader · $250k capital
Use case
Karim does arbitrage between crypto exchanges. MEV bots scan the mempool, see his transactions, and front-run his trades, eliminating his profit.
How they use it
- Keeps trading capital in Sentinel vault
- Maintains vaults on each exchange platform
- Transfers funds privately between exchange vaults
- MEV bots cannot see his movements
- Captures full arbitrage spread
Result
Zero front-running · +0.5-1% per trade recovered · Strategy remains private · Profitability restored
Individual — Crypto Salary
Julie, 26 · Remote developer · $80k/year in USDC
Use case
Julie receives her salary in USDC on Solana. All her transactions are public: colleagues can see her exact salary, family tracks her spending, friends know her savings.
How they use it
- Employer deposits salary directly to her Sentinel vault
- All daily spending comes from vault (stays private)
- No one can see her salary amount or expenses
- She controls what financial info to reveal
Result
Financial privacy restored · Can use crypto daily without surveillance · Personal security improved
Understanding Privacy Levels
Sentinel's privacy improves with network activity. The more users and transactions, the harder it becomes to trace individual flows.
| Network size | Transactions/day | Privacy level | Traceability |
|---|---|---|---|
| Early (1-10 users) | < 50 | Low (30%) | Possible with analysis |
| Growing (100-1000 users) | 500-5000 | Medium (60%) | Difficult |
| Mature (10000+ users) | 50000+ | High (90%+) | Nearly impossible |
“With thousands of users and tens of thousands of daily transactions, tracing individual flows becomes practically impossible, even with sophisticated chain analysis.”
What Sentinel CAN'T Hide
(Important Limits)
Sentinel provides strong privacy, but it's not magic. Here's what remains visible on-chain:
When you deposit or withdraw, the transaction is public. Anyone can see: wallet address, timestamp, and amount going in/out of the vault.
Transaction timestamps are public. If you deposit and immediately withdraw the same amount, this pattern is visible (though recipients aren't).
Your ISP and RPC provider can see your IP when you transact. Use a VPN if this is a concern for your threat model.
Creating a vault is a public transaction linked to your wallet. If someone knows your wallet, they know you have a Sentinel vault (but not the balance).
Key Insight: Sentinel hides WHO you pay, HOW MUCH, and your BALANCE. It does NOT hide THAT you're using Sentinel or WHEN you transact. Adjust your expectations accordingly.
Security Best Practices
Use a hardware wallet for large amounts. Never share your seed phrase. Enable all available security features on your wallet.
Wait before withdrawing after deposit. Immediate deposit-withdraw patterns are easier to link. Let funds sit for days/weeks.
Avoid unique round numbers. $1,234.56 is easier to track than $1,000. Vary your transaction amounts.
Separate treasury, payroll, and vendor flows with dedicated vault operations to reduce operational risk and simplify reviews.
Privacy improves as more people use Sentinel. Encourage others to adopt it for everyone's benefit.
Prepare selective disclosure packages from your private records to support audits, legal requests, and internal controls without exposing full activity.