Crypto虐狗记---”你“和小鱼（外传）

news2024/11/24 12:58:32

前言：剧情十(我没看见还有一个。。。。)

提示：

下载：

参数有了，直接搞就行。。。

参考：

*crypto*练2--攻防世界--easy_ECC - kubopiy - 博客园 (cnblogs.com)

大佬的脚本：

攻防世界 easy_ECC - diakla - 博客园 (cnblogs.com)

p = 15424654874903
a = 16546484
b = 4548674875
k = 546768
gx = 6478678675
gy = 5636379357093


def ksm(a, b):
    # print(a)
    r = 1
    a = (a % p + p) % p
    aa = a
    while b:
        if b & 1:
            r = r * a % p
        a = a * a % p
        b >>= 1
    print(aa * r % p)
    return r


def add(x1, y1, x2, y2):
    # k=((ay-by)*ksm((ax-bx+p)%p,p-1)%p+p)%p;
    # a=((k*k-ax-bx)%p+p)%p
    # b=(k*(ax-(a-p))%p+p)%p
    # print(x1,end=" ")
    # print(y1);
    # print(x2,end=" ")
    # print(y2);
    if x1 == None:
        return x2, y2
    if x2 == None:
        return x1, y1

    if x1 == x2 and y1 != y2:
        return None, None

    if x1 == x2:
        m = (3 * x1 * x1 + a) * ksm(2 * y1 % p, p - 2)
    else:
        m = (y1 - y2) * ksm((x1 - x2) % p, p - 2)
    # print(m%p)
    x3 = m * m - x1 - x2
    y3 = y1 + m * (x3 - x1)
    return x3 % p, -y3 % p


# k=k-1
rx = None
ry = None
while k:
    if k & 1:
        rx, ry = add(rx, ry, gx, gy)
    # print(gx,end="     ")
    # print(gy)
    gx, gy = add(gx, gy, gx, gy)
    k >>= 1
    # print(rx,end=" ")
    # print(ry)

print(rx + ry)

# 19477226185390

。。。牛逼。