CLIL2

Cryptography

Fill in the Blanks

What is the first type of key cipher in which both Alice and Bob have the same key?

(DOUBLE - ASYMMETRIC - SYMMETRIC - SESSION)

Multiple Choice

What was the problem of symmetric-key cipher?

• If someone intercepts the encrypted message, they can rewrite it using another new key and send it to the recipient

• It’s not always feasible to assume that both Alice and Bob possess a unique key unknown to others

• It’s not always easy to use

• It’s not possible to encrypt a message with a key and use the same key to decrypt it

Fill in the Blanks

What is the second type of key cipher in which both Alice and Bob have their own pair of keys (public and private)?

(DOUBKLE - ASYMMETRIC - SYMMETRIC - SESSION)

Multiple Choice

What was the problem of asymmetric-key cipher?

• If someone intercepts the encrypted message, they can rewrite it using another new key and send it to the recipient

• It’s not always feasible to assume that both Alice and Bob possess a unique key unknown to others

• It’s not always easy to use

• It’s not possible to encrypt a message with a key and use the same key to decrypt it

Fill in the Blanks

What is the third type of key cipher in which both Alice and Bob have their own pair of keys (public and private)?

(DOUBLE - ASYMMETRIC - SYMMETRIC - SESSION)

Multiple Choice

What was the problem of double-key cipher?

• If someone intercepts the encrypted message, they can rewrite it using another new key and send it to the recipient

• Sending an encrypted message is now very costly

• It’s not always easy to use

• It’s not possible to encrypt a message with a key and use the same key to decrypt it

Fill in the Blanks

What is the last type of key cipher that solves all the problems?

(DOUBKLE - ASYMMETRIC - SYMMETRIC - SESSION)

Open Ended

How does a double-key cipher work? How many keys are used in a conversation between two parties?