Please help!
pic_original.bmp
The file pic.original.bmp can be downloaded from this lab's website, and it contains a simple picture. We would like to encrypt this picture, so people without the encryption keys cannot know what is in the picture. Please encrypt the file using the ECB (Electronic Code Book) and CBC (Cipher Block Chaining) modes, and then do the following: 1. Let us treat the encrypted picture as a picture, and use a picture viewing software to display it. How ever, For the .bmp file, the first 54 bytes contain the header information about the picture, we have to set it correctly, so the encrypted file can be treated as a legitimate .bmp file. We will replace the header of the encrypted picture with that of the original picture. We can use the bless hex editor tool (already installed on our VM) to directly modify binary files. We can also use the following commands to get the header from pl.bmp, the data from p2.bmp (from offset 55 to the end of the Gle), and then combine the header and data together into a new file. $ head - 54 pl.bmp > header $ tail +55 p2.bmp > body $ cat header body > new.bmp 2. Display the encrypted picture using a picture viewing program (we have installed an image viewer program called eog on our VM). Can you derive any useful information about the original picture from the encrypted picture? Please explain your observations Select a picture of your choice, repeat the experiment above, and report your observations The file pic.original.bmp can be downloaded from this lab's website, and it contains a simple picture. We would like to encrypt this picture, so people without the encryption keys cannot know what is in the picture. Please encrypt the file using the ECB (Electronic Code Book) and CBC (Cipher Block Chaining) modes, and then do the following: 1. Let us treat the encrypted picture as a picture, and use a picture viewing software to display it. How ever, For the .bmp file, the first 54 bytes contain the header information about the picture, we have to set it correctly, so the encrypted file can be treated as a legitimate .bmp file. We will replace the header of the encrypted picture with that of the original picture. We can use the bless hex editor tool (already installed on our VM) to directly modify binary files. We can also use the following commands to get the header from pl.bmp, the data from p2.bmp (from offset 55 to the end of the Gle), and then combine the header and data together into a new file. $ head - 54 pl.bmp > header $ tail +55 p2.bmp > body $ cat header body > new.bmp 2. Display the encrypted picture using a picture viewing program (we have installed an image viewer program called eog on our VM). Can you derive any useful information about the original picture from the encrypted picture? Please explain your observations Select a picture of your choice, repeat the experiment above, and report your observations
