Public Key

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Definition 1

A Public Key1) Elaine Barker, NIST, Recommendation for Key Management: Part 1 - General, NIST Special Publication 800-57 Part 1, Revision 5, May 2020, Accessed 18 January 2022, https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-57pt1r5.pdf . is a cryptographic key used with a Public Key Cryptographic Algorithm that is uniquely associated with an entity and that may be made public. In an asymmetric-key (Public Key) cryptosystem, the Public Key has a corresponding Private Key. The Public Key may be known by anyone and, depending on the algorithm, may be used, for example:

Verify a digital signature that was generated using the corresponding Private Key,Encrypt keys that can be decrypted using the corresponding Private Key, orCompute a shared secret during a key-agreement transaction.

Definition 2

In cryptography, a Public Key is a large numerical value that is used to encrypt data. The key can be generated by a software program, but more often, it is provided by a trusted, designated authority and made available to everyone through a publicly accessible repository or directory.

A Public Key is also used to encrypt a message or check the legitimacy of a digital signature. It is accompanied by a corresponding private key, which is known only to its owner. Private keys are used to decrypt messages that were created with the corresponding Public Key or to create signatures. In other words, a Public Key locks up data from unauthorized use, while a private key is used to unlock it.

Public Keys are available from a Certificate Authority (CA), which issues Digital Certificate that prove the owner's identity and contain the owner's Public Key. Public Keys are created using an asymmetric algorithm, which pairs the Public Key with an associated private key. The most common algorithms used to generate Public Key are Rivest-Shamir-Adleman, elliptic curve cryptography, and Digital Signature Algorithm.

A Public Key can be given to any person with whom an individual wants to communicate, whereas a private key belongs to the individual it was created for and isn't shared. The Public Key is typically stored on a Public Key Infrastructure (PKI) server and is used to encrypt data securely before it is sent over the internet.

Source: https://searchsecurity.techtarget.com/definition/public-key