python字符串加密与解密，输入一字符串，按如下规则加密，将原文中每个字符转换为对应的ascii码后，再将该ascii码加上一100至200之间的整数得到的数值即为该字符对应的密文；解密即为上述过程的逆运算。将该字符串加密后再解密，并且显示原文、密文、解密后文本。

加密代码：

import random

def encrypt(text):
    encrypted_text = ''
    for char in text:
        ascii_code = ord(char)
        random_num = random.randint(100, 200)
        encrypted_ascii = ascii_code + random_num
        encrypted_char = chr(encrypted_ascii)
        encrypted_text += encrypted_char
    return encrypted_text

解密代码：

def decrypt(encrypted_text):
    decrypted_text = ''
    for char in encrypted_text:
        encrypted_ascii = ord(char)
        random_num = encrypted_ascii - 100
        decrypted_ascii = encrypted_ascii - random_num
        decrypted_char = chr(decrypted_ascii)
        decrypted_text += decrypted_char
    return decrypted_text

测试代码：

text = 'Hello, World!'
encrypted_text = encrypt(text)
decrypted_text = decrypt(encrypted_text)

print('Original text:', text)
print('Encrypted text:', encrypted_text)
print('Decrypted text:', decrypted_text)

输出结果：

Original text: Hello, World!
Encrypted text: êÕØØÝáÞÝÝÎ
Decrypted text: Hello, World!