M1522.002300 Internet Security (Fall 2022)

Programming Assignment #1: RSA Encryption/Decryption

This can be download from Github at https://github.com/BECATRUE/is-pa1/.

Student info

• ID: 2020-10015
• Name: Jaehun You (유재훈)
• Email: jaehun0121@snu.ac.kr
• Phone: 010-3894-9521

0. Compile

$ make

1. Generate keys

$ ./rsa -keygen [p] [q]
$ ./rsa -keygen 112349 203431

Public key
   e: 203449
   n: 22855269419

Private key
   d: 22020622969

The generated keys are stored in ./key.

• Both p and q must be prime numbers.
• The generated keys are stored in ./key.

2. Encrypt

$ ./rsa -encrypt

Plaintext
   : 202010015

Encrypted ciphertext
   : 9239585899

The encrypted ciphertext is stored in ./text/ciphertext.

• The plaintext must be stored in ./text/plaintext.
• The plaintext must be a positive integer.
• The keys must be stored in ./key.

3. Decrypt

$ ./rsa -decrypt

Ciphertext
   : 9239585899

Decrypted plaintext
   : 202010015

Original plaintext (identical)
   : 202010015

The decrypted plaintext is stored in ./text/plaintext.

• The ciphertext must be stored in ./text/ciphertext.
• The keys must be stored in ./key.