Security Model

TezosX Wallet is testnet software — do not use it to manage mainnet funds. This page documents the security properties it provides and the assumptions it makes.

Key storage

Data	Location	Cleared on
Encrypted vault (mnemonic)	chrome.storage.local	Manual reset / reinstall
Derived keys (tz1, sk, pk)	Service worker memory only	Lock, SW restart, browser close
Password	Never stored	N/A

The secret key (edsk…) exists in memory only while the wallet is unlocked. Calling lock() or allowing the service worker to restart clears it immediately. There is no way to extract the key from a locked wallet without the password.

Vault encryption

password ──PBKDF2-SHA256(200 000 iters)──► derivedKey (256-bit)
mnemonic ──AES-256-GCM──► ciphertext

• PBKDF2 with 200 000 SHA-256 iterations makes a dictionary attack expensive on commodity hardware (≈ seconds per guess rather than microseconds)
• AES-256-GCM provides authenticated encryption — tampering with the ciphertext is detectable
• A fresh random 256-bit salt and 96-bit IV are generated on every vault write

Origin spoofing prevention

The injected provider rejects messages not originating from the same window:

window.addEventListener('message', (event) => {
  if (event.source !== window) return;   // drop cross-frame messages
  ...
});

Request envelopes include the origin captured by the content bridge (window.location.origin), not a value supplied by the page. This prevents a malicious page from claiming a different origin to access sessions belonging to another site.

Approval gate

Every eth_requestAccounts and eth_sendTransaction call blocks on an explicit user decision in the approval popup. The service worker never forwards these requests to the provider without a confirmed 'approve' decision.

What "lock" resets

Calling lock() or having the service worker restart resets the following:

• UnlockedIdentity (tz1, publicKey, secretKey) — cleared
• RelayerProvider instance — set to null
• evmAlias cache — set to null
• ApprovalQueue — all pending requests rejected with 4001

The encrypted vault in chrome.storage.local and all StoredSession records are not affected by lock.

Threat model

Threat	Mitigated?	Notes
Password brute-force on stolen vault	Partially	PBKDF2 slows attacks; strong password recommended
Memory scraping while unlocked	No	Key is in SW memory; Chrome process isolation is the only barrier
Malicious web page accessing window.ethereum	Yes	Approval popup required for all sensitive methods
Cross-origin message injection	Yes	event.source !== window check
dApp claiming wrong origin	Yes	Origin captured by content bridge, not page-supplied
Extension code tampering	Out of scope	Requires malicious extension or compromised build

Testnet disclaimer

This wallet targets the Tezos X Previewnet exclusively. The UI shows a persistent testnet badge. RPC endpoints, contract addresses, and chain IDs are hardcoded to testnet values in packages/wallet/src/lib/constants.ts. Do not attempt to use this wallet on Tezos mainnet or Etherlink mainnet.