How to run this C++ code in ubuntu?

Question

How to run this C++ code in ubuntu?

I have compiled this code: https://github.com/vbdaga/Rabbit-Cipher/blob/master/rabbit.cpp
with g++ rabbit.cpp -o Rabbit but there are nowhere instructions on how to pass the arguments. I see only getline which do not help… I use Ubuntu 22.04.2 if that helps… Does anyone has any idea how to proceed?

Asked By: just_learning

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Answer 1

The rabbit.cpp file appears to contain a minimal test program for the encryption library – you can pass it arguments, but it will ignore them:

$ g++ -Wunused-parameter -o Rabbit rabbit.cpp 
rabbit.cpp: In function ‘int main(int, const char**)’:
rabbit.cpp:9:14: warning: unused parameter ‘argc’ [-Wunused-parameter]
    9 | int main(int argc, char const *argv[])
      |          ~~~~^~~~
rabbit.cpp:9:32: warning: unused parameter ‘argv’ [-Wunused-parameter]
    9 | int main(int argc, char const *argv[])
      |                    ~~~~~~~~~~~~^~~~~~

Instead, it reads parameters from the input.txt file:

key:
2115 55464 876543 3213 6456 79 6546 312
IV:
654897 32135
plaintext_size:
300000000

(well technically it reads from std::cin, after reopening input.txt on the standard input stream). As shipped, it doesn’t provide any means to enter plaintext – it simply stuffs the plaintext vector with plaintext_size zero bytes:

    vector <unsigned int> plaintext;
    int len;
    cin>>len;
    for(int i=0;i<len;i++){
            int x;
            //cin>>x;
            plaintext.push_back(0);
    }

With the given plaintext_size of 300000000 that will produce an extremely large ciphertext output.

If you want to verify that the program works as intended, I suggest you modify input.txt corresponding to the example in the README.md file:

### Example

key1 = [0000 0000 0000 0000 0000 0000 0000 0000]

plain_text = [0000 0000 0000 0000 ]

iv = [0000 0000]

cipher_text = [ED B7 05 67 37 5D CD 7C D8 95 54 F8 5E 27 A7 C6]

i.e.

$ cat input.txt
key:
0000 0000 0000 0000 0000 0000 0000 0000
IV:
0000 0000
plaintext_size:
4

Then ./Rabbit should produce the following output.txt:

$ cat output.txt 
01100111000001011011011111101101
01111100110011010101110100110111
11111000010101001001010111011000
11000110101001110010011101011110

which you can confirm contains the expected ciphertext bytes for example using

$ perl -ne 'printf "%Xn", unpack("L", pack("B*", $_))' output.txt 
EDB70567
375DCD7C
D89554F8
5E27A7C6

Answered By: steeldriver