加密文件上传到服务器，然后由另一个用户访问。具备离线存储支持的文件传输应用程序。

以下是一个基于Python的示例代码，用于加密文件并上传到服务器，然后由另一个用户访问。该示例使用了Flask和PyCryptodome库，并支持离线存储。

首先，安装所需的库：

pip install Flask pycryptodome

然后，创建一个名为server.py的Python文件，用于创建服务器端：

from flask import Flask, request, send_file
from Crypto.Cipher import AES
from Crypto.Random import get_random_bytes
from Crypto.Util.Padding import pad
import os

app = Flask(__name__)

@app.route('/upload', methods=['POST'])
def upload():
    # 生成随机密钥和IV
    key = get_random_bytes(16)
    iv = get_random_bytes(16)

    # 创建AES加密器
    cipher = AES.new(key, AES.MODE_CBC, iv)

    # 获取上传的文件
    file = request.files['file']

    # 加密文件内容
    encrypted_file = cipher.encrypt(pad(file.read(), AES.block_size))

    # 将加密文件保存到服务器
    with open('encrypted_file.bin', 'wb') as f:
        f.write(encrypted_file)

    # 将密钥和IV保存到服务器
    with open('key.txt', 'wb') as f:
        f.write(key)
    with open('iv.txt', 'wb') as f:
        f.write(iv)

    return 'File uploaded successfully.'

@app.route('/download', methods=['GET'])
def download():
    # 从服务器获取密钥和IV
    with open('key.txt', 'rb') as f:
        key = f.read()
    with open('iv.txt', 'rb') as f:
        iv = f.read()

    # 创建AES解密器
    cipher = AES.new(key, AES.MODE_CBC, iv)

    # 读取加密文件
    with open('encrypted_file.bin', 'rb') as f:
        encrypted_file = f.read()

    # 解密文件内容
    decrypted_file = cipher.decrypt(encrypted_file)

    # 创建解密后的文件
    with open('decrypted_file.txt', 'wb') as f:
        f.write(decrypted_file)

    return send_file('decrypted_file.txt', as_attachment=True)

if __name__ == '__main__':
    app.run()

创建一个名为client.py的Python文件，用于上传文件到服务器：

import requests

url = 'http://localhost:5000/upload'

file_path = '/path/to/file.txt'

files = {'file': open(file_path, 'rb')}

response = requests.post(url, files=files)

print(response.text)

创建一个名为receiver.py的Python文件，用于从服务器下载文件：

import requests

url = 'http://localhost:5000/download'

response = requests.get(url)

with open('downloaded_file.txt', 'wb') as f:
    f.write(response.content)

print('File downloaded successfully.')

请根据需要修改代码中的文件路径和服务器地址。运行server.py文件以启动服务器，然后运行client.py文件上传文件到服务器。最后，运行receiver.py文件从服务器下载文件。