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Definition: What is a public key?

A public key is created in public key encryption cryptography that uses asymmetric-key encryption algorithms. Public keys are used to convert a message into an unreadable format. Decryption is carried out using a different, but matching, private key. Public and private keys are paired to enable secure communication.
A pair of public key and private key is often also referred to as a keypair.
Learn more about the definition of private key.

Explanation: What are public keys used for?

A public key may be placed in an open access directory for decryption of the digital signature of the sender, the public key of the message recipient encrypts the sender’s message. Public key infrastructure (PKI) produces public and private keys.
The open access public key may also be e-mailed to trusted contacts and users. Pretty Good Privacy (PGP) is a popular form of public key cryptography. Public PGP keys are housed in a public key server directory to allow public key sharing. PGP server directory keys may be updated but not removed.

Applications of public keys

  • Digital signatures
  • Public key cryptography
  • Public key infrastructure
  • Cryptography
  • Encrypted messaging
  • Encrypted data exchanges
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