Sending file through UDP Socket

Introduction

(THIS is a repost, original post can be found on DNX Group blog)
User Datagram Protocol or UDP is a simple protocol. This protocol is unreliable - when a data packet is sent, it cannot be not known if it will reach its destination or not. There is no acknowledgement, retransmission, or timeout. When multiple data is sent at once, the order which they arrive cannot be predicted. They might be out of order. The data that is sent with sequence 1,2,3 might be recieved as 2,3,1. So, sending files through UDP socket is a bit difficult.

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Making passcode application in C#

This is a tutorial making a simple passcode application in C#
Video tutorial is included :)

Requirements:

• Visual Studio with C#
• Basic knowledge of C# and Programming

Quick step-by-step:

Step 1: Create a new project

• Start Microsoft Visual Studio 2010
• In Menu, click File - New - Project
• Select Visual C#
• Select Windows Form Applications
• Name your project, eg. Passcode
• Click OK

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How to make a simple virus/malware scanner

Making a working antivirus is a very hard thing because of several reason:

1. You need to get virus/malware sample which is not easy to get.
2. Most virus infect the executable file and some use polymorphism making it harder to detect.
3. Most antivirus use heuristics scan which analyze the file and if the file look suspicious it will flag it and ask the user what to do. This is hard to implement and poor heuristics scan can result many false-positive.
4. Need a driver which will monitor the system like file read/write.
5. etc...

Today, I'm going to show you how to make a simple malware scanner (not antivirus) in MSVC2008 C/C++ which use hash to compare file with database. This methods only works on some kind of malware, eg. worm, trojan, or any file which doesn't change itself because we will hash the whole file content.

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