the combination of a public key and a private key is known as a public - key cryptography.
the combination of a public key and a private key is known as a public - key cryptography.
the combination of a public key and a private key is known as a?
public - key cryptography
this is what the certificate authority mechanism is intended to prevent. a certificate authority (ca) is an organization that stores public keys and their owners, and every party in a communication trusts this organization (and knows its public key). when the user's web browser receives the public key from www.bank.example it also receives a digital signature of the key (with some more information, in a so-called x.509 certificate). the browser already possesses the public key of the ca and consequently can verify the signature, trust the certificate and the public key in it: since www.bank.example uses a public key that the certification authority certifies, a fake www.bank.example can only use the same public key. since the fake www.bank.example does not know the corresponding private key, it cannot create the signature needed to verify its authenticity.
certificate authority
identity-based systems allow any party to generate a public key from a known identity value such as an ascii string. a trusted third party, called the private key generator (pkg), generates the corresponding private keys. to operate, the pkg first publishes a master public key, and retains the corresponding master private key (referred to as "master key"). given the master public key, any party can compute a public key corresponding to the identity by combining the master public key with the identity value. to obtain a corresponding private key, the party authorized to use the identity "id" contacts the pkg, which uses the master private key to generate the private key for identity "id".
id-based encryption