A passkey prompt takes seconds, and a <code>recentBlockhash</code> expires after about 150 slots. Some wallets therefore use durable nonces, so a transaction can be signed now and submitted later. The nonce account is a public account that each transaction advances, so every transaction using it is linked, and so is whoever created and funded it.

A reused nonce account ties every transaction that uses it together.

Durable nonce accounts link pre-signed transactions

To avoid a biometric prompt for every action, some passkey wallets let the passkey authorize a short-lived <code>ed25519</code> session key, often stored in the browser. The registration transaction links the session key to the vault. Every transaction signed by the session key is then attributable to you, and if the browser storage leaks, so does spending power until the session expires.

Temporary ed25519 keys that avoid repeated prompts are registered on-chain.

Session keys are identities too

Wallets build transactions in recognizable ways: a fixed <code>SetComputeUnitLimit</code> and <code>SetComputeUnitPrice</code> pair, a particular instruction order, the same address lookup tables, the same tip account for a block-engine bundle. Combined with the precompile instruction, this shape usually identifies which passkey wallet you use, and narrows the set of people you could be.

Compute budget values, instruction order, and lookup tables fingerprint who built the transaction.