# Need an expert in C and number theory

I need a function in C that:

1- takes base, exponent, and modulus .i.e. modular_pow(base, exponent, modulus).

The base is binary and it is 128-bits, the exponent is integer and it is 128-bits, and the modulus is integer and it is 512-bits. Since C has no primitive data types that can hold 128-bits or 512-bits, you many need to use char!! then converting char to integer for multiplications and for taking the modulus.

2- The function must perform Square and Multiply algorithm the Right-to-left binary method, this algorithm reduce the complexity. i.e. 2^23 need only 9 multiplications instead of 22. Here is the pseudocode.

modular_pow(a, e, n)

convert e to binary: ks ks-1 ... k1 k0

b = a^b0 ; c = a;

for(i=1, i<=s; i++) {

c = c*c mod n;

if (ki == 1)

b = b * c mod n ;

}

return b;

3- Must works on Arduino UNO.

Before you propose, please please make sure that you fully understand the complexity of this function!!.

Kĩ năng: Thuật toán, Lập trình C

Về Bên Thuê:
( 0 nhận xét ) Milford, United States

ID dự án: #16319907

## Được trao cho:

samiridwy

Hello, i have experience with this kind of projects, message me so we can discuss cheers --------------------------

\$77 USD trong 1 ngày
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super2lao

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jpStar

Dear sir I am a C/C++, Algorithm and Math expert I read your project description I am interested in your project I want to discuss more details on chat Thank youi

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trutony

Hi, I am a talented C & C++ coder. I won the championship 4 times in the international online programming contest sponsored by India. If you give me this project, you will get good result. Thanks. Relevant skills & ex Thêm

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Gaosong2017

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dslc

Hi. I have an Arduino UNO to test this on. Would it be okay if I need to resort to assembly code for certain functionality? (It might not be necessary - but I just wanted to check.) I certainly don't regard myself a Thêm

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freelancerSolvit

I don't have an actual Arduino UNO so I will implement and test the code in a virtual Uno simulation environment. By the way, did you mean C++ instead of C?

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sohaibmughal1232

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ehabmedhat

i have done something similar to this before in c , as i used to multiply and add long number 1000 digit we could extend it if you want . i have used to take numbers as char and compute operation on them . Thêm

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yasithmilinda

I am a computer science and engineering undergraduate with a lot of knowledge in languages like C and optimization in algorithm level using number theory.

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aamiryousafi822

My name is Aamir Yousafi. I was raised in the U.S. I have a passion for the natural sciences, and here on Freelancer.com, [url removed, login to view], and [url removed, login to view], I am a science writer, software programmer, and medical coder. I have Thêm

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agurjew

I am ready to write the function you asked for. I understand the complexity of the function but I know I can write it. The only thing is that I do not know anything about Arduino UNO.

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hamzanaveed18

I am c/c++ developer. I ensure you that i will do the finest work because i have experience in that kind of stuff.

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CrazyWebGuru

Hello, I read about your project. And I have made the program just runs as you described. It was so easy, in fact. Call me, and you will get the result at once. Thank you.

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