Simulation lab 6.1: module 06 apply steganography to deliver a secret message ✅ Uy Tín
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Bùi Văn Quân đang tìm kiếm từ khóa Simulation lab 6.1: module 06 apply steganography to deliver a secret message được Update vào lúc : 2022-12-18 08:00:11 . Với phương châm chia sẻ Kinh Nghiệm Hướng dẫn trong nội dung bài viết một cách Chi Tiết 2022. Nếu sau khi tham khảo nội dung bài viết vẫn ko hiểu thì hoàn toàn có thể lại Comment ở cuối bài để Admin lý giải và hướng dẫn lại nha.In this assignment, you'll write two short programs: one which hides a short, secret message in an image file, and a second program which reads the hidden message back out of the image.
Nội dung chính Show- When using steganography to hide a message?Is used to physically hide a message?What is your message when decrypted?Which type of encryption technology is used with the BitLocker application?
In order to keep the program simple, your program will only hide short messages in PPM files (a simple, uncompressed format). Hidden messages are a maximum of 255 characters. As a sample, two files are provided, TU.ppm, and TU_modified.ppm, both of which look identical, and both have exactly the same file size, however the 2nd file contains the hidden text "Super secret message. Spooky".
A PPM file has the following format:
A "magic number", specifying the file type. PPM files have magic number "P6" (in ASCII)
Whitespace (this could be a blank, tab, carraige return, line feed, …)
Optional comments. A comment is a line which begins with #. Your program may safely ignore all comments.
The width in pixels of the image in ASCII.
The height in pixels of the image in ASCII.
The maximum color value in ASCII. Your program need only handle the value "255".
A single whitespace character.
Pixel data. You need only handle files with a maximum color value of 255, so each pixel will be represented by three bytes, one byte each for red, green, and blue. If your image is X rows by Y columns, then the file will contain X*Y*3 bytes of data, plus a header.
This program should take the following as command-line arguments:
A secret message, given as a string.
The name of an image file.
The name to give the output file, i.e., the image file containing the secret message.
if the file does not begin with the text "P6", print an error message and quit.
Read and ignore comments, if any.
Read the number of rows and colums of pixels. If there are an insufficient number of bits in the file in order to hide the message specified, print an error message and quit.
Read the maximum color value. If this is not 255, you may print an error message and quit. Otherwise, we can assume that each pixel of the file is represented as three one-byte values, corresponding to the level of red, green, and blue of the pixel.
Hide a message in the PPM data.
As we discussed in class, you're going to hide your message in the least significant bits of pixel data in the image. So, for example, if we're going to hide a particular byte b in the image, the 8 bits of b will be spread across the least significant bits of 8 bytes of the image file (i.e., hidden in the data for 2 2/3 pixels).
So that the message reading program knows how long the hidden message is, and knows when to stop reading, before hiding the bytes of the message itself, hide the message length.
If you're unclear about how to hide the message, think of the lab where you implemented the arithmetic operations using bit operators. What you need to do here isn't nearly as tricky.
This program should take a single command-line argument, the name of the file containing the hidden message.
ReadMsg should read the PPM header, then hidden in the least-significant bits of the pixel data, it should read the length of the message, which is hidden in a single byte spread across the first 8 data bytes of the picture. It should then read the hidden message itself and print it to the screen.
To receive extra credit points, the required parts of the assignment must be working properly.
Max 20 points. Add the ability to work with files with a 64k color depth in addition to the standard 256 colors. For files using 64k color depth, use the low-order two bits of each color to store messages instead of the the low order bit.
Max 10 points. Use the GNU getopt library and use switches for your command-line arguments:
-v for verbose. print more debugging output to the screen
-i for the input image file
-o for an output image file
-m for the secret message
-h to print a help message to the screen
Max 5 points. Suggest another file format. Find another uncompressed binary image file format which has a very simple header.
Organize your programs into four files:
stego.h contains declarations of constants, structs, functions, etc., common to both programs
stego.c the implementation of functions common to both programs
WriteMsg.c the message hiding program
ReadMsg.c the message reading program
tools and other resources
gdb is your friend. Get to know it.
hexdump can be very helpful. Use it to examine the image file without the hidden message and then the corresponding image file including the secret message. For example, here is what the TU file looks like after running it through hexdump.
A completely white PPM file for you to use for testing. Once you've written your program and you're trying to figure out why it's not working, you'll understand why this could come in handy.
Gimp is a không lấy phí graphics editor; it's been ported to most popular operating systems. You can use this to create and view ppm files. Maybe it'll also come in handy some time in the future if you don't feel like shelling out the money for Photoshop.
More information on the ppm format can be found on the netpbm sourceforge page. Note that there are several other file formats discussed on the page (including a version of PPM which stores the image data in ASCII and not binary. These have a magic number of P3, and not P6. Please don't confuse yourself by reading about the wrong file format).
Send a tar or zip file containing all of your source files along with a README file containing a road map for your code, along with instructions for how to build it.
We'll talk about tar in class. As usual, your program should be well documented. To make things easier for your lab instructor, please be sure to include your name the top of all of your source files, place your code in a directory named something like Stego_YourLastName, which itself will be inside a tar called Stego_YourLastName.tar or zipfile called Stego_YourLastName.zip
When using steganography to hide a message?
When using steganography to hide a message you can increase the protection of a message by using cryptography to encrypt the message. Examine the choices provided and select the one that describes encrypted information.Is used to physically hide a message?
Steganography (/ˌstɛɡəˈnɒɡrəfi/ ( listen) STEG-ə-NOG-rə-fee) is the practice of representing information within another message or physical object, in such a manner that the presence of the information is not evident to human inspection.What is your message when decrypted?
Decryption is the process of converting an encrypted message back to its original (readable) format. The original message is called the plaintext message. The encrypted message is called the ciphertext message.Which type of encryption technology is used with the BitLocker application?
BitLocker uses Advanced Encryption Standard (AES) as its encryption algorithm with configurable key lengths of 128 bits or 256 bits. The default encryption setting is AES-128, but the options are configurable by using Group Policy. Tải thêm tài liệu liên quan đến nội dung bài viết Simulation lab 6.1: module 06 apply steganography to deliver a secret message