用python实现Shamir-secret-share

采用 galois 的python库（https://github.com/mhostetter/galois ），快速写了一个在扩GF(2^m)上的 [t,n] 门限的Shamir-secret-sharing 流程；

document写的也很详细使用起来非常趁手。缺点就是效率略低一些。

https://pypi.org/project/galois/#polynomial-construction 

代码如下：

import numpy as np
import galois 

# Apply GF calculation implement Shamir Secret Share
# system parameter
# field param

n = 10
t = 6
F_num = 2**8
GF256 = galois.GF(F_num)


def distribute_shares(s):
    # Construct the polynomial and distribute the shares 
    # 
    print('The secret is :',s)
    powers =[i for i in range(t-1,-1,-1)]
    coeffs = [np.random.randint(F_num) for _ in range(t-1)]
    # append the secret as intercept;
    coeffs.append(s)
    p = galois.Poly.Degrees(powers, coeffs, field=GF256)
    print('construct the polynomials:',p)

    # randomly generate n points 
    secret_shares =[]
    xp = np.random.choice(range(F_num),n,replace=False)
    secret_shares = [str(xi)+'-'+str(int(p(xi).base)) for xi in xp]
    return secret_shares


def reconstruct_secret(collected_shares):
    # reconstruct the secret with collected shares 
    if len(collected_shares) != t:
        return np.nan
    x = []
    y = []
    for item in collected_shares:
        xi = int(item.split('-')[0])
        yi = int(item.split('-')[1])
        x.append(xi)
        y.append(yi)

    ss_0 = GF256(0)
    for i in range(t):
        item = GF256(y[i])
        for j in range(t):
            if i!=j:
                item *= -1*GF256(x[j])/(GF256(x[i])-GF256(x[j]))
        ss_0 += item
    return int(ss_0.base)
  
    
# generate secret shares
secret_shares = distribute_shares(33)

# collect random share 
collected_shares = np.random.choice(secret_shares,t,replace=False)
print('Randomly selected t shares \'x-y\':')
print(collected_shares)

recon_secret = reconstruct_secret(collected_shares)
print('Reconstructed secret:',recon_secret)

标签：python,galois,shares,GF256,item,secret,collected,Shamir
来源： https://blog.csdn.net/chenxin0215/article/details/118344295