Secure Communications

The video tutorial explains the one-time pad encryption method, which ensures secure communication by using a random cryptographic key. The key must be as long as the message, shared secretly between parties, and used only once to prevent statistical patterns. The tutorial highlights the importance of key sharing and the risks of eavesdropping if the key is compromised.

What is the primary characteristic of the cryptographic key in a one-time pad?

• It is known to everyone.

• It is shorter than the message.

• It is a random sequence with no statistical pattern.

• It is a sequence of repeating patterns.

Why is it crucial for both parties to have the same cryptographic key?

• To make the message appear longer.

• To allow the recipient to decrypt the message.

• To ensure the message is encrypted twice.

• To confuse potential eavesdroppers.

What happens if an eavesdropper intercepts the cryptogram without the key?

• They receive a duplicate of the key.

• They can easily decrypt the message.

• They can guess the message with some effort.

• They see a random string with no pattern.

Which of the following is a necessary condition for the one-time pad to remain secure?

• The key must be shorter than the message.

• The key can be reused multiple times.

• The key should be shared with multiple parties.

• The key must be kept secret and used only once.

What risk arises from reusing cryptographic keys in a one-time pad system?

• The message becomes longer.

• Statistical patterns may emerge, compromising security.

• The key becomes more random.

• The message becomes unreadable.