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What is a Public Key?

· Editorial Team · · ~4 min read

Public Key — A cryptographic code derived from a private key using one-way mathematics. It generates the wallet address used to receive funds and verifies signatures without exposing the private key.

How It Works

01 The wallet applies elliptic curve multiplication to the private key to derive the public key — a one-way function that cannot be reversed.
02 The public key is hashed to produce the wallet address (e.g., an Ethereum or Bitcoin address) that users share to receive funds.
03 When a transaction is signed with the private key, the network uses the public key to mathematically verify the signature.
04 The public key can be safely shared, while the private key must remain secret.

Why It Matters

▸ Public keys enable asymmetric cryptography — the foundation of secure, trustless blockchain transactions.
▸ They let users receive funds without exposing the secret that controls them, enabling public addresses.
▸ The one-way derivation guarantees that an attacker with the public key cannot compute the private key.
▸ Public keys power signature verification, enabling the network to confirm transactions without trusting the sender.

Common Questions

Is a public key the same as a wallet address?

Not exactly. The address is a hash of the public key, formatted for easier sharing. The public key itself is used for signature verification.

Can someone steal my crypto with my public key?

No. The public key can be safely shared. Only the private key can authorize transactions and access funds.

Why use both a public and private key?

Asymmetric cryptography lets anyone verify your signatures (public key) while only you can create them (private key), enabling trustless transactions.

What algorithm does Bitcoin use for keys?

Bitcoin and Ethereum use the secp256k1 elliptic curve for key generation, with ECDSA (and Schnorr in Bitcoin Taproot) for signatures.

References

  1. https://ethereum.org/en/developers/docs/accounts/
  2. https://bitcoin.org/en/how-it-works
  3. https://www.coinbase.com/learn/crypto-basics/what-is-a-public-key

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Educational content · Not financial advice · Trade at your own risk