python函数实现栅栏加密解密

Python中可以使用Fence cipher（栅栏密码）这种简单的替换式加密技术来加密和解密信息。Fence cipher通过将明文按行或列排列成矩阵，然后按照特定规则移动字符来实现加密。下面是一个基本的实现示例：

def fence_encrypt(text, rows):
    # 检查输入是否合法
    if not text or not isinstance(text, str) or rows <= 0:
        return "Invalid input"

    encrypted_text = []
    matrix = [[] for _ in range(rows)]

    # 将文本拆分为单个字符并放入矩阵
    row_index = 0
    for char in text:
        matrix[row_index].append(char)
        row_index += 1
        if row_index == rows:
            row_index = 0

    # 按照矩阵行顺序组合字符
    for i in range(len(matrix)):
        for j in range(i, len(matrix[0])):
            encrypted_text.append(matrix[j][i])

    return ''.join(encrypted_text)

def fence_decrypt(encrypted_text, rows):
    if not encrypted_text or not isinstance(encrypted_text, str) or rows <= 0:
        return "Invalid input"

    original_matrix = [[] for _ in range(rows)]
    decrypted_text = []

    # 逆向填充矩阵
    col_index = 0
    for char in encrypted_text:
        original_matrix[col_index].append(char)
        col_index += 1
        if col_index == rows:
            col_index = 0

    # 按照矩阵列顺序组合字符，恢复原始文本
    for i in range(len(original_matrix)):
        for j in range(i, len(original_matrix[0])):
            decrypted_text.append(original_matrix[i][j])

    return ''.join(decrypted_text)

# 示例
plaintext = "Hello, World!"
rows = 3
encrypted = fence_encrypt(plaintext, rows)
decrypted = fence_decrypt(encrypted, rows)

print(f"Encrypted: {encrypted}")
print(f"Decrypted: {decrypted}")