Public key cryptography is also known as asymmetric cryptography.
In asymmetric cryptography, two keys are used: a public key and a private key. The public key is shared with everyone, while the private key is kept secret. Messages encrypted with the public key can only be decrypted with the private key, and vice versa. This makes asymmetric cryptography ideal for secure communication, as it ensures that only the intended recipient can read the message.
Private key cryptography, on the other hand, uses a single key for both encryption and decryption. This means that if the key is compromised, then all messages encrypted with that key can be decrypted. As a result, private key cryptography is not as secure as asymmetric cryptography.
Symmetric cryptography is a type of cryptography that uses the same key for both encryption and decryption. This makes it less secure than asymmetric cryptography, as the key must be shared between the sender and receiver. However, it is faster and easier to implement than asymmetric cryptography.
None of the above is not a correct answer.