In this guide
Wallets and access
What is a private key?
What a private key is, how it differs from a seed phrase, what you can do with it, and why you never enter one into a random website or app.
Most crypto is controlled by a seed phrase, but older wallets (and some paper wallets) hold a private key directly: the single secret that proves control of the wallet. This page explains what that is, what it can do, and why it must never be entered anywhere casually.
The short answer
A private key is the secret itself. It is one key, usually a long string of letters and numbers (or a printed or exported key file), that signs transactions and proves control of the crypto. The address is safe to share; the private key never is.
The difference from a seed phrase: a seed phrase is the set of words that generates all of a wallet’s keys; a private key is one of those keys. One wallet can have many private keys (one per address) while the seed phrase restores them all. See what is a seed phrase.
What you can do with it
- With the correct, compatible wallet software, a private key can restore access to the wallet it belongs to.
- It can also sign a transaction, that is why it must stay secret.
- In an estate, a private key on paper or in a file means the wallet is accessible to whoever holds it, once legal authority is established.
What never to do
- Never enter a private key into a website, app, online tool or “checker” that asks for it. The only place it belongs is wallet software from the official channel that you are certain is genuine, or the device you control, after authority is confirmed, import sites that offer to “check” it are a common theft vector.
- Never photograph, scan or email it, and never type it into a website, app or form. The one legitimate place is the official device or wallet software you have verified, after authority is confirmed.
- Do not “test” it by importing it anywhere without knowing exactly what you are doing and why.
If you found one in an estate
- Preserve it exactly as found; note only that it exists and where.
- Confirm legal authority before anyone uses it, see legal authority vs technical access.
- Identify the format (WIF, hex, paper wallet or keystore file) with the wallet format library.
- If the estate cannot use it, that is a technical access question: wallet recovery: what is realistically possible.
New to these terms? Plain-language definitions are in the crypto inheritance glossary.
Quick answers to common questions
Is a private key the same as a seed phrase?
No. A seed phrase is the set of words that generates all of a wallet's keys. A private key is one single key (usually a long string or a file) that controls one wallet or address. The seed phrase can restore the keys; a private key is one of them.
Can I enter my private key somewhere to check it?
No. No official process asks you to send a private key, and entering it into a website or app that asks for it is how wallets are emptied. The one legitimate place is wallet software from the official channel that you are certain is genuine, or the device you control, after authority is confirmed. If you found one, preserve it and confirm legal authority before anyone uses it.
What do I do if I found a private key after a death?
Preserve it exactly as found and note only that it exists and where. Confirm who is legally allowed to act, then identify the format with the wallet format library before anything is touched.
Sources and useful links
- Bitcoin Wiki, Private keyChecked 2026-08-12