python实现栅栏密码加密代码

栅栏密码是一种简单的加密方式，下面是Python实现栅栏密码加密的代码：

def fence_cipher_encrypt(text, key):
    fence = [[] for i in range(key)]
    rail = 0
    direction = 1

    for char in text:
        fence[rail].append(char)
        rail += direction

        if rail == key:
            direction = -1
            rail = key - 2
        elif rail == -1:
            direction = 1
            rail = 1

    result = []
    for rail in fence:
        result += rail

    return ''.join(result)

其中，text是要加密的明文，key是栅栏的数量。这个函数会返回加密后的密文。

--相关问题--:
1. 栅栏密码有哪些应用场景？
2. 栅栏密码的加密强度如何？