Programming assignment 3

Problem 1

The public key and secret key is generated first, saved as 'p_key.txt' and 's_key.txt'.

The program can run in two modes: signing mode and verification mode;

Signing mode: data should be provided either in command line or from file 'datatosign.txt', they should be all in hex (omit the '\x' in front).

Verification mode: data to verify should be provided either in command line or from file 'rsa_signature.txt', it will show the verification result.

Problem 2

The RSA key generation function 'RSA_key_generation' is modified as requested.

Problem 3

In this part of the program a directory is locked as follows:

All the files are encrypted using CBC mode. A tags is generated for each file using a random symmetric key. After decrypting the symmetric keys using the private key of the locking party and the private key of the unlocking party, the unlocking party would have the symmetric keys. He the verifys the tages and decrypts the files using the recoverd keys. We also provided a function in order to have a chain of certificates but unfortunately we are not using it here.

How to run our interactive code

python programmingassignment3.py

Programming assignment 2

CBC, CTR, CBC_Mac, Hash_and_Mac and RSA implementation

CBC and CTR

We implemented this programming assignment in python. In this code we use exampleInputA.txt as the input plain text and exampleKeyOnes.txt as the key for CBC and CTR mode ciphers and CBC mac and Hash and mac. The results from each function are saved in a file. Here are the file names and their content:

content	file name
key	exampleKeyOnes.txt
plain text	exampleInputA.txt
CBC encryption	CBC_eccryption.txt
CBC decryption	CBC_decryption.txt
CBC IV	CBC_iv.txt
CTR encryption	CBC_encryption.txt
CTR decryption	CBC_decryption.txt
CTR IV	CTR_iv.txt

MAC

We use the same inputs(plain text and key) as the previous section to generate CBC mac and Hash and mac. The reasults are saved in CBC_mac.txt and hash_mac.txt. Files 'tag.txt' and 'message.txt' are provided in order to verify a massage and a tag. You can edit these files and use your own input in hex.

RSA

In this section we also use exampleInputA.txt file as the input. The results are saved in files as follows.

content	file name
Public key	p_key.txt
Private keys	s_key.txt
RSA encryption	rsa_encryption.txt
RSA decryption	rsa_decryption.txt

How to run our code

python programming_assignment_2.py