Cryptographic Attacks

Advanced Cryptography

 

1. What is the difference between a symmetric key and an asymmetric key?

 

1. How do low-power devices affect which encryption you choose to employ?

 

 

Task 6 – Cryptographic Attacks

 

1. What is cryptanalysis? Why is it important?

 

1. How can you protect yourself from a dictionary attack?
2. What are some countermeasures you can use to strengthen your cryptosystem?

 

Task 7 – Asymmetric Encryption

 

1. How do public keys differ from private keys? What is the relationship between the two?

 

1. For which type of environment is asymmetric cryptography best suited?
2. Why does asymmetric encryption require fewer keys than symmetric encryption?
3. What is the main use for the Diffie-Hellman protocol?

Suppose Bob uses the RSA cryptosystem with a very large modulus n for which the factorization cannot be found in a reasonable amount of time. Suppose Alice sends a message to Bob by representing each alphabetic character as an integer between 0 and 25 (A -> 0 , … , Z -> 25) and then encrypting each number separately using RSA with large e and large n.

Is this method secure? If not, describe the most efficient attack against this encryption method.

Solution: