DES Cipher Encryption

Objective

42 school project we will implements cipher text encryption in C without using most of the standard libary.

Allow funtion

• open
• close
• read
• write
• malloc
• free

Function cover

• base64
• des
• des-cbc
• des-ecb
• des3
• des3-ede
• des3-ede-cbc

Flag cover

base64:

• -e, encrption (default)
• -d, decryption
• -i, file input at next argument
• -o, file output at next argument

des:

• -a, decode/encode the input/output in base64, depending on the encrypt mode
• -d, decrypt mode
• -e, encrypt mode (default)
• -i, input file for message
• -k, key in hex is the next arguement. (Behave like openssl des -K not openssl des -k)
• -o, output file for message
• -p, password in ascii is the next argument. (Behave like a modifiedd openssl des -pass not like openssl des -p or -P)
• -s, the salt in hex is the next argument. (Behave like openssl des -S)
• -v, initialization vector in hex is the next argument. (Behave like openssl des -iv not openssl des -v)

How to use

clone the repository:

cd ~
git clone https://github.com/JCTGY/ft_ssl_des.git ft_ssl_des
cd ~/ft_ssl_des
make 

usage:

./ft_ssl base64 [-i file] [-o file] [-d] [-e]
./ft_ssl ciphername [-a] [-d] [-e] [-i file] [-v IV]
             [-k key]  [-o file] [-p pass] [-s salt]

Useful link

Base64 wiki algorithum
The DES Algorithm Illustrated by J. Orlin Grabbe
Data Encryption Standard wiki page
DES PDF from Cleveland State University
Encryption operating modes: ECB vs CBC
OpenSSL 3DES encrytion parameters
DATA ENCRYPTION STANDARD (DES)