# 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!!.

Skills: Algorithm, C Programming

( 0 reviews ) Milford, United States

Project ID: #16319907

## Awarded to:

samiridwy

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

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## 29 freelancers are bidding on average \$106 for this job

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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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dslc

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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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ehabmedhat

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sakthivelna

Requirement Details: - Need to implement modular_pow module in C - Understood Right to Left Algorithm to implemented for minimum multiplication - Need to run the code on Arduino UNO Constraints: - the base and e More

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prinshussnl540

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