Bài Thực Hành Số 4 - Comparing checksum between two files

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Background Information

• What is a file checksum?
  • A checksum or hash sum is used to check the integrity of the data inside of a file.  This file can be a regular text file, image, executable, or etc.
  • If the checksum published with a download file or by a person matches the checksum performed on the file of concern, then there is a good changed the data was not altered.
• What is Marxio File Checksum?
  • This program calculates and verify checksums of files downloaded received in email, upload from server, and downloaded from the internet. It supports major checksum types: CRC32, MD4, MD5, SHA1, SHA-256, SHA-384, SHA-512, RIPEMD-128, RIPEMD-160, HAVAL 256, TIGER 192.
• Resources
  • Unfortunately, development was discontinued on this tool.

Prerequisite: You Must Complete the QuickStego Lab

1. *** Lab Prerequisite ***
   • NOTE: Do not continue if you have not completed the QuickStego lab.
2. On Your Instructor VM
   • Navigate your Windows Explorer to C:\tools\Stego\
   • If you have not completed the QuickStego Lab, Click Here Before you Continue.
   
   
   • Remember that image file horse.bmp does NOT contain embedded text, and horse2.bmp DOES contain embedded text.
   
   
   • Notice:  These files are the same byte size (835 KB).
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Download Marxio-FCV

1. Login to your Instructor VM, as username administrator
   • For those of you that do not have access to my class, Instructor VM is a Windows XP Operating System.
2. On the Instructor VM,
   • Pull up Internet Exploder or Firefox
     • Go To http://download.cnet.com/3001-18514_4-10913355.html?spi=748bb18d406b8dd4e6a5f35d19eb5aa8. 
     
     
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3. Click on Save (See Below).
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4. Save to C:\tools\CheckSum
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Section 1: Run Marxio-FCV.exe

1. Using Windows Explorer Navigator to C:\tools\CheckSum
   • Double Click on Marxio-FCV.exe
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2. Click on Run
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3. Click on Accept License Agreement
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4. Click on OK
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5. Click On NO
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6. Click OK
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Section 2: Comparing CheckSums with Marxio

1. Click on the Folder in the red rectangle (See Below).
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2. Select horse.bmp
   • Click on Open
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3. Viewing the CheckSum
   • After opening the file, the checksum will automatically be calculated.
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4. Highlight the checksum, and click copy.
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5. Paste the Checksum you just copied into the "Compare with:" textbox.
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6. Now we will open up horse2.bmp to compare its' checksum with horse1.bmp.
   • Click on the folder within the red rectangle.
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7. Select horse2.bmp
   • Click Open.
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8. Notice the Red X, indicates the file checksums do not match.
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