编写程序·题目: ·1、编程实现棋盘密码的加密和解密 ·2、编程实现m组的栏栅密码的加密和解密 ·3、编程实现k (k<26)情况下的凯撒密码的加密和解密 ·基本要求： ·1、支持自定义输入，输入长度无限制 ·2、m=2,k=3必须实现 ·3、语言不限 ·可选要求： ·m和k为自定义输入 ·图形化界面，可以文本文件进行输入和输出

以下是Python实现的三个算法（棋盘密码、栏栅密码、凯撒密码）的加密和解密，支持自定义输入，输入长度无限制。

1. 棋盘密码：

import string

def encrypt_chessboard(text, keyword):
    # 构造棋盘
    chessboard = [' ']*25
    keywords = list(set(keyword))
    for i in range(len(keywords)):
        chessboard[i] = keywords[i]
    for c in string.ascii_lowercase:
        if c not in keywords:
            chessboard[len(keywords)] = c
            keywords.append(c)
            if len(keywords) == 5:
                keywords.append(' ')
    # 加密
    cipher = ''
    for c in text.lower():
        if c in chessboard:
            row = chessboard.index(c) // 5
            col = chessboard.index(c) % 5
            cipher += str(row+1) + str(col+1)
        else:
            cipher += c
    return cipher

def decrypt_chessboard(cipher, keyword):
    # 构造棋盘
    chessboard = [' ']*25
    keywords = list(set(keyword))
    for i in range(len(keywords)):
        chessboard[i] = keywords[i]
    for c in string.ascii_lowercase:
        if c not in keywords:
            chessboard[len(keywords)] = c
            keywords.append(c)
            if len(keywords) == 5:
                keywords.append(' ')
    # 解密
    text = ''
    i = 0
    while i < len(cipher):
        if cipher[i].isdigit():
            row = int(cipher[i]) - 1
            col = int(cipher[i+1]) - 1
            index = row * 5 + col
            text += chessboard[index]
            i += 2
        else:
            text += cipher[i]
            i += 1
    return text

2. 栏栅密码：

def encrypt_railfence(text, m):
    # 构造加密矩阵
    matrix = [['']*len(text) for _ in range(m)]
    row, col, direction = 0, 0, 1
    for c in text:
        matrix[row][col] = c
        if row == m-1:
            direction = -1
        elif row == 0:
            direction = 1
        row += direction
        col += 1
    # 按列读取矩阵
    cipher = ''
    for j in range(len(text)):
        for i in range(m):
            if matrix[i][j]:
                cipher += matrix[i][j]
    return cipher

def decrypt_railfence(cipher, m):
    # 构造解密矩阵
    matrix = [['']*len(cipher) for _ in range(m)]
    row, col, direction = 0, 0, 1
    for _ in range(len(cipher)):
        matrix[row][col] = '*'
        if row == m-1:
            direction = -1
        elif row == 0:
            direction = 1
        row += direction
        col += 1
    # 按照矩阵填充明文
    index = 0
    for j in range(len(cipher)):
        for i in range(m):
            if matrix[i][j] == '*' and index < len(cipher):
                matrix[i][j] = cipher[index]
                index += 1
    # 按行读取矩阵
    text = ''
    row, col, direction = 0, 0, 1
    for _ in range(len(cipher)):
        text += matrix[row][col]
        if row == m-1:
            direction = -1
        elif row == 0:
            direction = 1
        row += direction
        col += 1
    return text

3. 凯撒密码：

import string

def encrypt_caesar(text, k):
    # 加密
    cipher = ''
    for c in text.lower():
        if c in string.ascii_lowercase:
            index = (string.ascii_lowercase.index(c) + k) % 26
            cipher += string.ascii_lowercase[index]
        else:
            cipher += c
    return cipher

def decrypt_caesar(cipher, k):
    # 解密
    text = ''
    for c in cipher.lower():
        if c in string.ascii_lowercase:
            index = (string.ascii_lowercase.index(c) - k) % 26
            text += string.ascii_lowercase[index]
        else:
            text += c
    return text

m和k为自定义输入的话，只需要在函数中加上对应的参数即可。如果想要图形化界面，可以使用Python的Tkinter模块。