Cryptography

Question 1: You are required to learn the GPG/PGP package (learning the applications of private and public key cryptography to secure email messages and documents) to be able to answer the following questions. You should pair up with one of your class fellow to do this lab and record results and give commentary on the results.

a) Generate keys of 3 different sizes for RSA encryption scheme and include these keys in the report.

b) Check the key files and estimate the number of decimal digits of the keys and write your estimates.

c) Encrypt a file (text or binary) using 3 key sizes and include your results and note the observation

d) Explain why GPG encryption and decryption are quite fast.

e) Create a file of close to 1 MB size and encrypt and decrypt it and note the time taken. Comment on the reason why this much time has taken. Calculate how long it would take to do the encryption/decryption of a 10MBs of data.

f) Export your public key and discuss the reason why your exported key should be in ASCII format.

g) Encrypt a file and output the cipher text in ASCII format. Explain when you need cipher text in ASCII format.

h) You should work with your class fellow to do this experiment and record your observation in the form of commands being used or procedure being followed and includeyour results.

I. Exchange your public key and your friend's public key using email.

II. Import your friend's public key into your key ring.

III. Encrypt a file using your friend's public key and send the encrypted file to your friend.

IV. Ask your friend to decrypt the encrypted file.

V. You can ask your friend to do the same thing.

i) Write a reflection report in 100 words about the role of cryptography in securing communication of confidential documents.