diff --git a/recv/recv_net.py b/recv/recv_net.py
new file mode 100644
index 0000000..b6cc8af
--- /dev/null
+++ b/recv/recv_net.py
@@ -0,0 +1,108 @@
+import hashlib
+import json
+import selectors
+import socket
+import threading
+from time import sleep
+
+import select
+
+
+# from entity.Letter import Letter
+
+
+# def main():
+#     # 用户输入各种数据填充letter字段
+#     # 获取用户的公私钥对进行签名
+#     # 使用对方的公钥进行加密
+#     # 发送信件
+#     pass
+#
+#
+# def sendLetter(letter: Letter, target="192.168.195.162:8426"):
+#     # 向目标ip和端口发送指定的信件
+#     pass
+
+class recver():
+    def __init__(self):
+        self.file_name = ""
+        self.flle_size = 0
+        self.file_sha256 = ""
+        self.addr = ("", 0)
+        self.server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.server.bind(('127.0.0.1', 8425))
+        self.server.listen(10)
+
+    def recver_thread(self):
+        while True:
+            conn, addr = self.server.accept()
+            data = conn.recv(10240)
+            msg = json.loads(data.decode())
+            if int(msg['flag']) == 0:
+                print("\nhaved received data:"+msg["data"]+"\n")
+            elif int(msg['flag']) == 1:
+                self.recv_file(msg['data'])
+            else:
+                print("Error")
+
+    def send_thread(self, conn):
+        while True:
+            flag: int = int(input(""))
+            if flag == 0:
+                data = input("Enter data to send: ")
+                msg = {"flag": 0, "data": data}
+                msg = json.dumps(msg).encode("utf-8")
+                self.send_data(conn, msg)
+            elif flag == 1:
+                file_name = input("Enter file name to send: ")
+                self.send_file(conn, file_name)
+            else:
+                print("Error,plesae enter 0 to send data, or 1 to send file.")
+
+
+    def send_data(self, conn, data):
+        conn.sendall(data)
+
+    def send_file(self, conn, file_name):
+        data = "dawwaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        msg = {"flag": 1, "data": data}
+        msg = json.dumps(msg).encode("utf-8")
+        conn.sendall(msg)
+
+    def recv_data(self, conn):
+        con, addr = conn.accept()
+        data = con.recv(1024)
+        if not data:
+            return None
+        # print(data.decode())
+        return data.decode()
+    def main(self):
+
+        while True:
+            try:
+                client = socket.socket()  # 定义协议类型,相当于生命socket类型,同时生成socket连接对象
+                client.connect(('127.0.0.1', 8424))
+                print("Connected to recver.")
+                print("if you want to send data, enter 0, if you want to send file, enter 1.")
+                sleep(1)
+                break
+            except socket.error:
+                print("Waiting for recver...")
+        # 加入线程
+        threading.Thread(target=self.recver_thread, ).start()
+        threading.Thread(target=self.send_thread, args=(client,)).start()
+
+    def run(self):
+        threading.Thread(target=self.main).start()
+
+    def recv_file(self, data):
+        with open("3.txt", 'wb') as file:
+            print("Receiving file data...")
+            file.write(data)  # 写入数据到文件
+            print("File received successfully.")
+
+
+# test
+if __name__ == '__main__':
+    a = recver()
+    a.run()
\ No newline at end of file
diff --git a/sender/sender_net.py b/sender/sender_net.py
new file mode 100644
index 0000000..15f59de
--- /dev/null
+++ b/sender/sender_net.py
@@ -0,0 +1,116 @@
+import hashlib
+import json
+import selectors
+import socket
+import threading
+from time import sleep
+
+import select
+
+# from entity.Letter import Letter
+
+
+
+# def main():
+#     # 用户输入各种数据填充letter字段
+#     # 获取用户的公私钥对进行签名
+#     # 使用对方的公钥进行加密
+#     # 发送信件
+#     pass
+#
+#
+# def sendLetter(letter: Letter, target="192.168.195.162:8426"):
+#     # 向目标ip和端口发送指定的信件
+#     pass
+
+class sender():
+    def __init__(self):
+        self.file_name=""
+        self.flle_size=0
+        self.file_sha256=""
+        self.addr=("",0)
+        self.server=socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.server.bind(('127.0.0.1', 8424))
+        self.server.listen(10)
+
+    def recver_thread(self):
+        while True:
+            conn, addr = self.server.accept()
+            data = conn.recv(10240)
+
+            msg=json.loads(data.decode())
+            if int(msg['flag']) == 0:
+                print("\nhaved received data:"+msg["data"]+"\n")
+            elif int(msg['flag']) == 1:
+                self.recv_file(msg['data'])
+            else:
+                print("Error")
+
+    def send_thread(self,conn):
+        while True:
+            flag:int=int(input())
+            if flag==0:
+                data=input("Enter data to send: ")
+                msg={"flag":0,"data":data}
+                msg=json.dumps(msg).encode("utf-8")
+                self.send_data(conn,msg)
+            elif flag==1:
+                file_name=input("Enter file name to send: ")
+                self.send_file(conn,file_name)
+            else:
+                print("Error,plesae enter 0 to send data, or 1 to send file.")
+
+
+
+
+    def send_data(self, conn, msg):
+        conn.sendall(msg)
+    def send_file(self, conn, file_name):
+        data = "dawwaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        msg={"flag":1,"data":data}
+        msg=json.dumps(msg).encode("utf-8")
+        conn.sendall(msg)
+
+    def recv_data(self,conn):
+        con, addr = conn.accept()
+        data = con.recv(1024)
+        if not data:
+            return None
+        # print(data.decode())
+        return data.decode()
+    # def recv_file(self,conn):
+    #     con, addr = conn.accept()
+    #     with open("3.txt", 'wb') as file:
+    #         print("Receiving file data...")
+    #         while True:
+    #             # 接收数据块
+    #             data = con.recv(2048)
+    #             if not data:
+    #                 break  # 如果没有更多数据则退出循环
+    #             file.write(data)  # 写入数据到文件
+    #         print("File received successfully.")
+    def recv_file(self,data):
+        with open("3.txt", 'wb') as file:
+            print("Receiving file data...")
+            file.write(data.encode("utf-8"))  # 写入数据到文件
+            print("File received successfully.")
+    def run(self):
+        threading.Thread(target=self.main).start()
+    def main(self):
+        while True:
+            try:
+                client = socket.socket()  # 定义协议类型,相当于生命socket类型,同时生成socket连接对象
+                client.connect(('127.0.0.1', 8425))
+                print("Connected to recver.")
+                print("if you want to send data, enter 0, if you want to send file, enter 1.")
+                sleep(1)
+                break
+            except socket.error:
+                print("Waiting for recver...")
+        #加入线程
+        threading.Thread(target=self.recver_thread, ).start()
+        threading.Thread(target=self.send_thread,args=(client,)).start()
+#test
+if __name__ == '__main__':
+    a=sender()
+    a.run()
\ No newline at end of file