Keeping your wallet safe

Simple

Kalda locks whenever you leave the app. Open it with your fingerprint, your face, or your phone's PIN, pattern or password. Your phone needs a screen lock for this to work.

You'll be asked again before every payment or swap, and before your recovery phrase is shown, so someone holding your unlocked phone still can't send your money.

Screenshots are blocked on screens that show secrets, and addresses you copy are cleared from the clipboard after a short while.

Never tell anyone your 12 words and never type them into a website or another app. Nobody from Kalda will ever ask for them; anyone who does is trying to steal from you.

Before paying, check the whole address and slow down if someone is rushing you. Pay saved contacts rather than copying addresses from your history.

Detailed

Your phone's own security

The app lock uses the authentication your phone already provides: fingerprint, face, PIN, pattern or password. Modern phones keep secrets in a hardware-backed secure area designed so other apps can't read them, even on the same device.

Asking again for every payment

Unlocking the app lets you look around. Moving money, revealing your phrase and other sensitive steps each need a fresh check, so a phone left unlocked on a table is still not enough to spend.

What no lock can protect

• Your recovery phrase works on its own. Anyone who has the words can rebuild your wallet on any device, without your phone or your fingerprint.
• Blockchain payments are final. A payment to a scammer is a valid transaction, and no network has a chargeback.
• A phone infected with malware can watch the screen. Keep your phone updated and install apps only from sources you trust.

Common scams

• Fake support, “wallet validation” or “sync” requests that ask for your phrase or ask you to scan a code into another app.
• Address poisoning: tiny payments from lookalike addresses, planted so you copy the wrong one from your history.
• Addresses swapped in emails, chats or web pages. Link Up with matching codes, and signed contact cards, avoid this.
• Urgency: real people rarely need money “right now”.

In depth

Secure hardware

Many phones include a secure element or trusted execution environment: a small, isolated processor with its own memory. Keys generated there can be used to encrypt and decrypt but are designed never to leave it, so even software with full control of the main system can't simply copy them out.

Biometrics as a gate

A fingerprint or face scan isn't a key itself. The phone's secure hardware compares the scan to a stored template and, on a match, releases permission to use a key it guards. The biometric data never needs to leave the device.

Defence in depth

Security engineers layer independent protections so that one failure isn't fatal: a device lock, an app lock, a fresh check for each sensitive action, and limits on what the screen and clipboard expose. An attacker has to defeat several of them, not just one.

The threat model

Every system protects against some attackers and not others. A self-custody wallet defends well against a thief holding a locked phone, but cannot defend against someone who already has the recovery phrase, or against a user persuaded to sign a payment. Knowing which is which is the core of staying safe.

Social engineering

Most crypto losses come not from broken cryptography but from people being persuaded to reveal a secret or approve a payment. Scams lean on urgency, authority and fear. Because a signed blockchain transaction can't be reversed, the only reliable defence is to slow down and verify through a channel you already trust.

Network privacy

Reading a balance means asking some server about an address. The server never learns your keys, but it can see which addresses are asked about together and from which network location, and could link them. Fresh addresses limit what the blockchain reveals, not what a data provider can observe.