A public key receives crypto and a private key spends it, CertiK and Coin Bureau explain in their guides to wallet keys. The two keys are made as a matched set, called a key pair. The public key can be shown to anyone. The private key must stay with its owner, because anyone who gets it can take the funds.
Key facts from the three explainers
- Pairing: Public and private keys come in pairs.
- Public key's job: Lets funds be sent to an address and checks signatures made by the matching private key.
- Private key's job: Signs, and gives the owner access to the funds and the power to make transactions, much like a card PIN.
- Direction: The public key comes from the private key. Working backwards is not practical.
- Address: A wallet address is a hashed version of the public key.
- The rule: Never give anyone the private key. CertiK applies the same rule to the seed phrase.
A code unique to one wallet
Coin Bureau describes each private key as a cryptographic code unique to one crypto wallet.
Why the link runs one way
The ssh.com Academy says the step from private key to public key is easy. Going the other way is not practical, it adds. CertiK states the same one-way rule: a public key comes from a private key, not the reverse. Coin Bureau describes the forward step only. It gives the Elliptic Curve Digital Signature Algorithm (ECDSA) as one example of an algorithm used for it.
The address is one more step
Coin Bureau says a wallet address comes from the public key through an extra hashing step. That gives a chain of three: private key, then public key, then address. Each one is made from the one before it. So the address a person shares to get paid is derived from the public key, not the key itself.
Signing a spend without a third party
CertiK counts public and private keys among the technologies that make cryptocurrencies possible. The reason it gives is that they let users transact without a third party checking each transaction. In the ssh.com description, the owner signs with the private key. The matching public key then verifies that signature.
In public-key cryptosystems, a private key is a key used for digitally signing documents.
Why the private key is the secret
CertiK calls one rule foundational to web3 security: do not give your private key or seed phrase to anyone. Its blog adds that real institutions and projects do not ask for either. A request for them deserves great caution. Coin Bureau describes the cost of breaking the rule. Handing over a private key compromises the wallet, which can lead to unauthorized access and lost funds.
Public keys: safe to share, with a caveat
Coin Bureau says a public key is safe to share. In its view, showing it does not open the wallet to theft or to transactions the owner did not approve. It still warns against posting public keys on insecure or suspicious platforms, because of the risk of phishing scams.
CertiK says attackers often try to get private keys through phishing attacks.
Public key vs private key
How do the public key and the private key differ on their job, who may see them, where they come from, what happens if they leak and what each one produces?
Each cell restates one explainer's general description; the table does not show how any particular wallet or platform handles keys.
Who holds the private key
CertiK says that with a non-custodial wallet, users are responsible for their own private keys. Coin Bureau spells out what that duty protects. A lost or exposed private key can mean the wallet's funds are lost for good or stolen. The reason, it says, is that blockchain transactions are irreversible. Its advice is to store private keys offline in hardware wallets, away from online threats.
What is confirmed and what is not
Three points rest on more than one outlet. The two keys work as a pair. The private key must not be shared, a warning found in two of the three. The private key cannot practically be worked out from the public key, according to ssh.com and CertiK. The latter also says a seed phrase encodes the private keys. None of the three explains how that encoding works. Other points come from a single outlet each: the extra hashing step for addresses, the phishing caveat on public keys, the hardware-wallet advice, and the advice that legitimate parties never ask for keys. No source here covers key formats or lengths, or how any platform stores keys. None of the three dates its own text. They were read on Oct. 13 and Oct. 14, 2026.
Analysis: the weak point is the key holder, not the math
The one-way link between the keys is what lets a public key be shown safely. That same link moves the weak point away from the math and onto the person holding the private key. The attack CertiK describes is phishing, which targets the owner rather than the cryptography. The design that removes a third party also removes anyone who could undo a mistake, since Coin Bureau calls blockchain transactions irreversible. For anyone using a non-custodial wallet, a request for a private key or seed phrase is the clearest warning sign.
Next step: checking an address
A public key's address is where funds arrive. Next, look up that address in a blockchain explorer to see the transactions tied to it. A separate explainer covers how to use a blockchain explorer to check a transfer.
Sources: What are Public and Private Keys? - CertiK (certik.com), accessed Oct 14, 2026 · Private & Public Keys (ssh.com), accessed Oct 13, 2026 · Private Vs Public Keys Wallets: Discover Their Key Differences (coinbureau.com), accessed Oct 14, 2026
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