python3脚本Base64加解密按行读取txt文件并写入

        在做CTF时遇到一个全是Base64编码的txt文件，一个一个解码太慢了，就自己写了个脚本，按行读取并解码后输出到文件中，并且可以多次解码。

下面是代码：

#-*- coding : utf-8 -*-
import base64

SaveList = []  # 存档列表
# 读取文本内容到列表
with open("1.txt", "r", encoding='utf-8') as file:
    for line in file:
        line = line.strip('\n')  # 删除换行符
        SaveList.append(line)
    file.close()

print("请选择加密（E）还是解密（D）：")
type=input()
if(type=='E'):
    print("请选择加密次数\n")
    index = input()
    count = eval(index)
    while(count>0):
        i = len(SaveList)
        while(i-1>=0):
            encode=base64.b64encode(SaveList[i-1].encode('utf-8'))
            SaveList[i-1]=str(encode,'utf-8')
            i=i-1
        count = count - 1

    # 写入存档到文件
    with open("result.txt", "a", encoding='utf-8') as file:
        for i in SaveList:
            file.write(i + '\n')
        file.close()
else:
    print("请选择解密次数")
    index = input()
    count=eval(index)
    while (count > 0):
        i = len(SaveList)
        while (i-1>=0):
            decode = base64.b64decode(SaveList[i-1])
            print(decode)
            SaveList[i-1] = str(decode, 'utf-8')
            i = i - 1
        count=count-1

    # 写入存档到文件
    with open("result.txt", "w", encoding='utf-8') as file:
        for i in SaveList:
            file.write(i + '\n')
        file.close()