Public Key
Metade compartilhável de um par de chaves, usada para receber fundos e verificar assinaturas; deriva da chave privada, mas não permite gastar os fundos.
Key points
- A public key is the shareable half of a cryptographic key pair, used to receive funds and verify signatures.
- It is derived from the private key, but the reverse path is infeasible: having the public key does not allow discovering the private one.
- It can be disclosed without risk, since it does not give anyone the power to spend the funds, only to verify and send them.
What is a public key?
A public key is one of the two parts of a key pair used in cryptography. It forms a pair with the private key: while the private key is secret and authorizes spending, the public key can be shared freely and is used to receive funds and verify signatures. A wallet's addresses are derived from it, that is, the destinations to which other people can send funds.
How it works
The public key is generated from the private key through a cryptographic operation that only works in one direction: it is easy to obtain the public key from the private one, but infeasible to do the reverse. This is what allows the public key to be disclosed without compromising security: even if everyone knows it, no one can use it to discover the private key or, therefore, spend the funds.
In practice, the public key fulfills two roles. First, it is the basis for receiving addresses: anyone who wants to receive funds shares an address derived from their public key, and anyone can send funds there. Second, it is used to verify signatures: when a transaction is signed with the private key, the network uses the corresponding public key to confirm that the signature is valid, without the secret being revealed.
This relationship between the two keys is the foundation of security in crypto. A user can disclose their public key and addresses to receive payments, without any risk of this allowing someone to move their funds. The power to spend remains exclusively with whoever holds the private key. Understanding this asymmetry, what can be shared and what needs to be kept safe, is essential to using crypto securely and without unfounded fears when disclosing an address.
Understanding the public key helps clearly distinguish what is safe to share from what must remain secret.
Why it matters
Understanding the public key helps explain why it is safe to share an address to receive funds and how the network verifies signatures without exposing secrets. Distinguishing the public part from the private one is essential for using crypto securely. This is a technical concept, and none of it represents any trading recommendation.
Risks and limitations
The public key itself can be shared without risk of spending, but disclosing addresses has privacy implications, since the entire associated history is public. The comfort of sharing the public key depends on the private key remaining genuinely secret. Confusing the two, exposing the private key, leads to loss of funds. None of this represents a trading recommendation.