internet

A Beginner’s Guide to Checksum

Are you wondering what a checksum is? You may have noticed that when you download files from certain websites, they have a very long string of numbers and letters called a checksum or MD5 checksum or SHA-1, etc. These really long strings basically act as fingerprints for that particular file, whether it be an EXE, ISO, ZIP, etc.

Checksums are used to ensure the integrity of a file after it has been transmitted from one storage device to another. This can be across the Internet or simply between two computers on the same network. Either way, if you want to ensure that the transmitted file is exactly the same as the source file, you can use a checksum.

The checksum is calculated using a hash function and is normally posted along with the download. To verify the integrity of the file, a user calculates the checksum using a checksum calculator program and then compares the two to make sure they match.

Checksums are used not only to ensure a corrupt-free transmission, but also to ensure that the file has not been tampered with. When a good checksum algorithm is used, even a tiny change to the file will result in a completely different checksum value.

The most common checksums are MD5 and SHA-1, but both have been found to have vulnerabilities. This means that malicious tampering can lead to two different files having the same computed hash. Due to these security concerns, the newer SHA-2 is considered the best cryptographic hash function since no attack has been demonstrated on it as of yet.

About 99.9% of the time, you really don’t need to care or worry about checksums when downloading files off the Internet. However, if you are downloading something sensitive like anti-virus or privacy software like Tor, it’s probably a good idea to verify the checksum because hackers can create malware-infested versions of critical software in order to gain full access to a system.

Windows has in-built checksum utility and it is very easy to use:

It can also calculate for MD2 MD4 MD5 SHA1 SHA256 SHA384 SHA512

Download Microsoft File Checksum Integrity Verifier

The MD5 & SHA Checksum Utility is my favorite utility for working with checksums because it has all the features I need in the free version.

 

Windows: Hide Internet Explorer 11 address bar & navigation bar

Applies to:

Windows Server 2008R2, Windows Server 2012R2, Windows 10

There are two ways this can be accomplished depending on your needs for the controlled environment.

GPO:

I would like to first clarify that there is not a single GPO to just hide TABS in IE11. There is however a way you can enforce IE in Full View Mode which by default will remove the TABS and Address bar via a GPO.

The GPO  you can use to enforce the Full-Screen view is available on both Computer and User configuration policy. Below is the gpo location path in group policy editor console.

  • GPO NAME: Enforce full-screen mode
  • LOCATION: Computer or User configuration – Computer Configuration\Administrative Templates\Windows Components\Internet Explorer
  • KEY LOCATION: Software\Policies\Microsoft\Internet Explorer\Toolbars\Restrictions

SCREENSHOT: GPO CONSOLE

2352.GPO-LOCATION

WINDOWS REGISTRY:

This will cause the IE address bar to not show. I disabled the Navigation bars too so it gives a clean window experience.

SCREENSHOT: REGISTRY LOCATION WITH VALUES

1172.GPO-REGISTRY-LOCATION

Download the Registry file.

The GPO and keys will cause the browser to open in full view with no address bar or tabs

7536.FULL-VIEW-AFTER-GPO