Part 1 a. How to encrypt a message using classical cryptography algorithms we co
ID: 3549684 • Letter: P
Question
Part 1
a. How to encrypt a message using classical cryptography algorithms we covered in class? Are these methods secure?
b. How to decrypt a message using classical cryptography
algorithms we covered in class? What method is the best if
you want to quickly decrypt the message?
Part 2
a.How to encrypt a message using block cipher algorithms we
covered in class? What are the similarities and differences
between those algorithms?
b. How to encrypt a message using a stream cipher?
c. Compare and contrast block cipher and stream cipher.
Explanation / Answer
1-A : classical cryptography has two basic components
1: Substitution : - In this the letters of message are replaced by other letters
2: Transposition :- In this the letters are rearranged in different order.
One example of classical cryptography technique is caeser cipher.
In this technique every letter of the message is replaced by the third next letter in alpbabets.
Like the message:
HENRY will be transformed to KHQUB
This technique is not secure.