What Is Public Key?
Also known as: Public Key Cryptography Key
In short
A public key is the key mathematically derived from the private key in asymmetric cryptography that can be safely shared with others. In cryptocurrencies, it is used to verify digital signatures and to generate wallet addresses.
In public-key cryptography, every user has two linked keys. The private key is kept secret and is used to sign transactions; the public key lets anyone verify that a signature was truly created by the owner of that private key. In Bitcoin and Ethereum, this relationship is based on elliptic curve cryptography using the secp256k1 curve.
The public key can easily be computed from the private key, but doing the reverse is practically impossible with current computers. The security of the system rests on this one-way property. Wallet addresses are usually not the public key itself but a shortened form of it passed through hash functions. For example, an Ethereum address consists of the last 20 bytes of the Keccak-256 hash of the public key.
Sharing your public key or address is enough for someone to send you crypto and does not put your funds at risk. However, it is debated whether sufficiently powerful quantum computers could weaken elliptic curve cryptography in the future; for this reason, the long-term security of addresses whose public keys have become visible on-chain is a subject of research.
Last updated: · This content is for information purposes only and is not investment advice.