c++ euclidean algorthm // modular inverse help

[undone wave]

That's not how this works. You need to explain what is your problem here. If it's not too long to explain in DM, it isn't too long to explain it here

[gusty wigeon]

Ok sry

[fresh basalt]

does DM typing go 2x as fast or what?

[gusty wigeon]

i didn’t know dm had word count too like damn

[undone wave]

You can send multiple messages to add all information you need

And please read and follow the #📄・posting-guidelines. They will help you ask for help properly.

[undone wave]

That's a nice homework. Can you please explain more in details what you need help with exactly? What have you tried? What don't you understand? What prevents you from achieving you goal? ...

[gusty wigeon]

The code is sending sry

The one I have, there’s minor mistakes idk how to address

[undone wave]

Ok sorry. We're use to people sending their homework with nothing else.

Check the #📄・posting-guidelines. It shows how to properly send code

[gusty wigeon]

can yall see the last 8 lines or should i send them via another file

[undone wave]

We can see them don't worry

[gusty wigeon]

ok thank u sorry if the code itself is messy I lost my mind writing it

[gusty wigeon]

@fresh basalt @undone wave do either of y’all think you could help me 😞

[undone wave]

Not right now. Add more details about what you're trying to do more exactly, why it's not working and where in the code it could be great for other or us to help you

Again, I recommend that you look at the #📄・posting-guidelines and make sure you post follows them

[gusty wigeon]

I don’t understand what the output of the code would be

From the instructions

[naive rivet]

I think it's really nice to understand the details of RSA,
but seriously, anyone should use a proper crypto library in production,
not cook their own, within reason 😬

[gusty wigeon]

hi- i updated this code, now it’s mostly right but my assert isn’t working

https://pastecord.com/ydepajenub

[gusty wigeon]

https://sourceb.in/v0FiTzj6pj this is my code
im having issues with the encrypting and decrypting functions, by using rsa algorithms
the encrypting of the number doesnt work and ive tried anythign can someone pls look at the code with a fresh set of eyes :((

im almost done

[undone wave]

What do you mean "it doesn work" what doesn't work? Can you please explain what you want and what you get that isn't right.

You tried everything? What have you tried? Can you explain what you tried and why it didn't work?

Please read and follow the #📄・posting-guidelines when asking for help. It takes 2 minutes to read and will save us a lot of time ping ponging 🏓 questions.

[gusty wigeon]

the encrypting of the message does not work. the encrypt and decrypt function are not working. i have tried multiple different ways to try and present the formula to change them and it doesn’t give me the output I should be getting.

[glossy shore]

Hi @gusty wigeon, Can you review your RelativelyPrime() function ?
You need e value = (p-1)(q-1)

I think you are close to solving the assignment; if you review your instructions again; you will find your error right away

I hope that helps!

[gusty wigeon]

hi thank you for answering me

[gusty wigeon]

So should I call the function to get E?

or maybe do relativelyprime(phi);?

[glossy shore]

I think you can set your p and q as random values; and calculate your e = RelativelyPrime(p, q).

The e should be RelativelyPrime to (p-1)*(q-1); which is a prime number closer to it!

||
std::vector<int> relativelyPrime(int p, int q) {
std::vector<int> result;
phi = (p - 1) * (q - 1);
for (int i = 1; i < phi; ++i) {
if (gcd(i, phi) == 1) {
result.push_back(i);
}
}
return result;
}||

[naive rivet]

I don't think this would work for any p/q values over 32-bit 😬

[glossy shore]

That’s true @naive rivet, but the assignment is just for 32 bit integers

[naive rivet]

so you might need ~8 GiB of RAM (~2 billion * 4 bytes = 32 bits after removing even numbers 😛 )

[gusty wigeon]

i hate c++ sm how do i get good

[gusty wigeon]

yes this is exactly what i did thanks i just saw this

int phi = (P - 1) * (Q - 1);
int PQ = P * Q;
// e is equivalent to the relative prime of phi: (p-1)*(q-1)
int e = RelativelyPrime (phi);
// d is equal to inverse modular of e and phi
int d = inverse (e, phi);

that’s what i submitted