ECC加密
.全称:椭圆曲线加密(Elliptic Curve Cryptography)
,ECC加密算法是一种公钥加密技术,以椭圆曲线理论为基础。利用有限域上椭圆曲线的点构成的Abel群离散对数难解性,实现加密、解密和数字签名。将椭圆曲线中的加法运算与离散对数中的模乘运算相对应,就可以建立基于椭圆曲线的对应密码体制。
"""考虑K=kG ,其中K、G为椭圆曲线Ep(a,b)上的点,n为G的阶(nG=O∞ ),k为小于n的整数。则给定k和G,根据加法法则,计算K很容易但反过来,给定K和G,求k就非常困难。因为实际使用中的ECC原则上把p取得相当大,n也相当大,要把n个解点逐一算出来列成上表是不可能的。这就是椭圆曲线加密算法的数学依据点G称为基点(base point)k(k<n)为私有密钥(privte key)K为公开密钥(public key)
"""def get_inverse(mu, p):"""获取y的负元"""for i in range(1, p):if (i*mu)%p == 1:return ireturn -1def get_gcd(zi, mu):"""获取最大公约数"""if mu:return get_gcd(mu, zi%mu)else:return zidef get_np(x1, y1, x2, y2, a, p):"""获取n*p,每次+p,直到求解阶数np=-p"""flag = 1 if x1 == x2 and y1 == y2:zi = 3 * (x1 ** 2) + a mu = 2 * y1 else:zi = y2 - y1mu = x2 - x1if zi* mu < 0:flag = 0 zi = abs(zi)mu = abs(mu)gcd_value = get_gcd(zi, mu) zi = zi // gcd_value mu = mu // gcd_valueinverse_value = get_inverse(mu, p)k = (zi * inverse_value)if flag == 0: k = -kk = k % p"""x3≡k2-x1-x2(mod p)y3≡k(x1-x3)-y1(mod p)"""x3 = (k ** 2 - x1 - x2) % py3 = (k * (x1 - x3) - y1) % preturn x3,y3def get_rank(x0, y0, a, b, p):"""获取椭圆曲线的阶"""x1 = x0 y1 = (-1*y0)%p tempX = x0tempY = y0n = 1while True:n += 1p_x,p_y = get_np(tempX, tempY, x0, y0, a, p)if p_x == x1 and p_y == y1:return n+1tempX = p_xtempY = p_ydef get_param(x0, a, b, p):"""计算p与-p"""y0 = -1for i in range(p):if i**2%p == (x0**3 + a*x0 + b)%p:y0 = ibreakif y0 == -1:return Falsex1 = x0y1 = (-1*y0) % preturn x0,y0,x1,y1def get_graph(a, b, p):"""输出椭圆曲线散点图"""x_y = []for i in range(p):x_y.append(['-' for i in range(p)])for i in range(p):val =get_param(i, a, b, p) if(val != False):x0,y0,x1,y1 = valx_y[x0][y0] = 1x_y[x1][y1] = 1print("椭圆曲线的散列图为:")for i in range(p): temp = p-1-i if temp >= 10:print(temp, end=" ")else:print(temp, end=" ")for j in range(p):print(x_y[j][temp], end=" ")print("") print(" ", end="")for i in range(p):if i >=10:print(i, end=" ")else:print(i, end=" ")print('\n')def get_ng(G_x, G_y, key, a, p):"""计算nG"""temp_x = G_xtemp_y = G_ywhile key != 1:temp_x,temp_y = get_np(temp_x,temp_y, G_x, G_y, a, p)key -= 1return temp_x,temp_ydef ecc_main():while True:a = int(input("请输入椭圆曲线参数a(a>0)的值:"))b = int(input("请输入椭圆曲线参数b(b>0)的值:"))p = int(input("请输入椭圆曲线参数p(p为素数)的值:")) if (4*(a**3)+27*(b**2))%p == 0:print("您输入的参数有误,请重新输入!!!\n")else:breakget_graph(a, b, p)print("user1:在如上坐标系中选一个值为G的坐标")G_x = int(input("user1:请输入选取的x坐标值:"))G_y = int(input("user1:请输入选取的y坐标值:"))n = get_rank(G_x, G_y, a, b, p)key = int(input("user1:请输入私钥小key(<{}):".format(n)))KEY_x,kEY_y = get_ng(G_x, G_y, key, a, p)k = int(input("user2:请输入一个整数k(<{})用于求kG和kQ:".format(n)))k_G_x,k_G_y = get_ng(G_x, G_y, k, a, p) k_Q_x,k_Q_y = get_ng(KEY_x, kEY_y, k, a, p) plain_text = input("user2:请输入需要加密的字符串:")plain_text = plain_text.strip()c = []print("密文为:",end="")for char in plain_text:intchar = ord(char)cipher_text = intchar*k_Q_xc.append([k_G_x, k_G_y, cipher_text])print("({},{}),{}".format(k_G_x, k_G_y, cipher_text),end="-")print("\nuser1解密得到明文:",end="")for charArr in c:decrypto_text_x,decrypto_text_y = get_ng(charArr[0], charArr[1], key, a, p)print(chr(charArr[2]//decrypto_text_x),end="")if __name__ == "__main__":print("*************ECC椭圆曲线加密*************")ecc_main()