文件访问和加密(python) Caesar 算法

2024-07-16 21:03| 来源: 网络整理| 查看: 265

设计一个具有图形用户界面的文件加密和解密程序。

（1）设计一个加密类，使用 Caesar 算法，实现文本文件的加解密功能。

（2）设计一个图形化用户界面的 Python GUI 程序，实现文件的读取、写入。并调用设计的类，对文件内容进行加密解密。

（3）测试程序，验证程序功能。运行程序，例如打开一个文本文件 A，对该文件进行加密生成文件 B，再对文件 B 进行解密生成文件 C，对比文件 A 与文件 C 是否相同，并检查文件 B 是否被加密。

（4）完善程序功能，对可能出现问题进行处理，使程序可以友好提示并正常结束。

GUI 程序，实现文件读取写入以及加密和解密

from tkinter.filedialog import askopenfilename, asksaveasfilename from tkinter import * from tkinter import messagebox from tkinter import simpledialog from Caesar import Caesar class FileEncryption: def __init__(self): window = Tk() window.title("文件加密") menubar = Menu(window) window.config(menu=menubar) frame0 = Frame(window) frame0.grid(row=1, column=1, sticky=W) newImage = PhotoImage(file="new.gif") openImage = PhotoImage(file="open.gif") saveImage = PhotoImage(file="save.gif") Button(frame0, image=newImage, command=self.newFile).grid(row=1, column=1, sticky=W) Button(frame0, image=openImage, command=self.openFile).grid(row=1, column=2) Button(frame0, image=saveImage, command=self.saveFile).grid(row=1, column=3) Button(frame0, text="加密", command=self.EncryptText).grid(row=1, column=4) Button(frame0, text="解密", command=self.DecryptText).grid(row=1, column=5) frame1 = Frame(window) frame1.grid(row=2, column=1, sticky=W) lblFile = Label(frame1, text="文件名").pack(side=LEFT) self.filename = StringVar() self.filename.set('') enfile = Entry(frame1, textvariable=self.filename).pack(side=LEFT) frame2 = Frame(window) frame2.grid(row=3, column=1) scrollbar = Scrollbar(frame2) scrollbar.pack(side="right", fill=Y) self.text = Text(frame2, width=40, height=20,wrap=WORD, yscrollcommand=scrollbar.set) self.text.pack() scrollbar.config(command=self.text.yview) window.mainloop() def newFile(self): self.text.delete(1.0, END) self.filename.set('') def openFile(self): self.text.delete(1.0, END) filename = askopenfilename() if filename != '': infile = open(filename, "r", encoding=" utf-8") try: for line in infile: self.text.insert(END, line) except Exception as e: messagebox.showerror("错误", f"读取文件时出错: {e}") else: infile.close() self.filename.set(filename) def saveFile(self): filename = asksaveasfilename() try: if filename == '': raise ValueError outfile = open(filename, 'w', encoding="utf-8") outfile.write(self.text.get(1.0, END)) except FileNotFoundError: messagebox.showerror("错误", "文件不存在或已被删除") except Exception: messagebox.showinfo("提示", "你取消了对话框") else: messagebox.showinfo("提示", "保存成功！") outfile.close() self.filename.set(filename) def EncryptText(self): key = simpledialog.askstring("输入密钥", "请输入Caesar密钥!") try: if not key: raise ValueError("密钥不能为空！") key = int(key) except ValueError as e: messagebox.showerror("错误", f"输入的密钥无效: {e}") else: c = Caesar(key) cipertext = c.getEncryptedText(self.text.get(1.0, END)) self.text.delete(1.0, END) self.text.insert(END, cipertext) messagebox.showinfo("提示", "加密完成") def DecryptText(self): key = simpledialog.askstring("输入密钥", "请输入Caesar密钥!") try: if not key: raise ValueError("密钥不能为空！") key = int(key) except ValueError as e: messagebox.showerror("错误", f"输入的密钥无效: {e}") else: c = Caesar(key) text = c.getDecryptedText(self.text.get(1.0, END)) self.text.delete(1.0, END) self.text.insert(END, text) messagebox.showinfo("提示", "解密完成") FileEncryption()

Caesar 加密

class Caesar: def __init__(self,key = 3): self.__key = key self.__code="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrst"\ "uvwxyz 1234567890~!@#$%^&*()_+=[]{}|\\::\'\",.?/" def getDecryptedText(self,ciperText): clearText = "" j = 0 for i in ciperText: if i in self.__code: j = (self.__code.find(i)-self.__key)%len(self.__code) clearText += self.__code[j] else: clearText += i return clearText def getEncryptedText(self,clearText): ciperText = "" j = 0 for i in clearText: if i in self.__code: j = (self.__code.find(i)+self.__key)%len(self.__code) ciperText += self.__code[j] else: ciperText += i return ciperText def getKey(self): return self.__key def setKey(self,key): self.__key = key def getCode(self): return self.__code def setCode(self,code): self.__code = code

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