Asymmetric Encryption and Key Exchange

The video tutorial discusses the importance of encryption keys and the challenges of securely sharing them over the internet. It explains out-of-band key exchange methods, such as using couriers, and in-band key exchange using asymmetric encryption for session keys. The tutorial also covers creating symmetric keys with public key cryptography, allowing secure key exchange without transmitting the key over the network.

Why is it important for the encryption key to be known only by the person encrypting and decrypting the data?

• To allow multiple people to access the data

• To reduce the cost of encryption

• To make the encryption process faster

• To ensure the data remains confidential

What is a logistical challenge when encrypting a large amount of data across the internet?

• Finding a fast encryption algorithm

• Sharing the encryption key securely

• Reducing the size of the data

• Ensuring the data is readable

Which of the following is NOT an example of out-of-band key exchange?

• Sending the key via email

• Exchanging the key in person

• Calling someone on the telephone

• Using a courier

What does in-band key exchange involve?

• Sending the key across the network

• Using a physical medium to transfer the key

• Avoiding the use of any network

• Encrypting the key with a symmetric algorithm

How can asymmetric encryption be used in in-band key exchange?

• By using the same key for encryption and decryption

• By encrypting the symmetric key with a public key

• By avoiding the use of any keys

• By using a physical medium to transfer the key

What is a session key?

• A key that is shared publicly

• A key that never changes

• A key used for multiple sessions

• A key used for a single session and then discarded

Why are session keys considered ephemeral?

• They are used for multiple sessions

• They are used temporarily and then discarded

• They are never encrypted

• They are shared with everyone

How can a client securely send a session key to a server?

• By sending it in plain text

• By encrypting it with the server's public key

• By calling the server on the telephone

• By using a courier

What is the advantage of using public key cryptography to create symmetric keys?

• It reduces the cost of encryption

• It allows multiple people to access the data

• It makes the encryption process faster

• It avoids sending the symmetric key across the network

How do Bob and Alice create the same symmetric key without sending it across the network?

• By combining Bob's private key with Alice's public key and vice versa

• By using the same symmetric key for both

• By sending the symmetric key in plain text

• By using a courier to transfer the key