6.7

RSA

a cryptosystem for public-key encryption, and is widely used for securing sensitive data, particularly when being sent over an insecure network such as the Internet.

digital certificate

a data packet that certifies the holder of a public key.

public key cryptography

a public key known to everyone and a private or secret key known only to the recipient of the message. When Bob wants to send a secure message to Alice, he uses Alice's public key to encrypt the message. Alice then uses her private key to decrypt it.

symmetric cipher

cipher in which a single key is used for both encryption and decryption.

asymmetric cipher

cipher is one in which separate but related keys are used for encryption and decryption.

Diffie-hellman

an algorithm used to establish a shared secret between two parties. It is primarily used to exchange a symmetric cryptographic key among two parties, Alice and Bob, who wish to communicate securely.

SSl

is a protocol for establishing an encrypted link between a web server and a browser.

HTTPS

is a protocol for secure (trusted, encrypted) communication over the Internet.

certificate authority

is an entity that issues digital certificates.

the key exchange problem

the problem of sharing a secret cryptographic key between Alice and Bob without Eve being able to intercept it.

trust model

The use of a trusted third party to verify the trustworthiness of a digital certificate.

intractable

A computational problem is intractable if the only known way to solve the problem depends on an exponential algorithm.