Public Key Cryptography Sample Clauses

Public Key Cryptography. ‌ In modern cryptography, there’s a difference between symmetric and asymmetric cryp- tosystems. In symmetric cryptography, there is only one secret key used between the sender and the receiver. Thus, the same key is used for both encryption and decryption. Symmetric primitives include block ciphers, stream ciphers, cryptographic hash func- tions, and message authentication codes (MACs). Common to all symmetric cryptosys- tems is that the parties who wish to communicate need some prior secret established before distributing keys. This is usually achieved by establishing a secure channel to a trusted authority (TA) who then issues a common secret key to both parties. In comparison to symmetric-key cryptosystems, the main idea of asymmetric or public key cryptosystems is to make key distribution easier. It is asymmetric in the sense that each party has a key pair, a public key and a private key. Respectively, these are used for encryption and decryption. Although the keys have some cryptographic relation, the public key can be widely distributed without compromising the private key. Thus, any party who wish to communicate with another party can encrypt the message using the recipient’s public key who then can decrypt it using his or her private key. It is also possible to sign data, in which the private key is used for signing and the public key is used for verification. Unlike symmetric-key cryptography, there is no need for having established a secret prior to interaction.

Public Key Cryptography. The public key cryptography (PKC) is introduced by Xxxxxx and Xxxxxxx [5]. PKC involves two different keys for encryption and decryption instead of sin- gle key as symmetric key system. Since, public key is random string in PKC. Therefore, To prove the relation between entity and its public key, PKC adopts certificate mechanism where certificate-based protocols work by considering that each entity has a public and private key pair. These public keys are authenti- cated via certificate authority (CA) which issue a certificate. When two entities wish to establish a session key, a pair of ephemeral (short term) public keys are exchanged between them. The ephemeral and static keys are then combined in a way so as to obtain the agreed session key. The authenticity of the static keys provided by signature of CA assures that only the entities who posses the static keys are able to compute the session key.