Encrypt it, like it’s hot: 7zip Your Cloud Files, BitLocker Your Drives

Digi
4 min readOct 12, 2024

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We all use cloud services like Google Drive, Microsoft OneDrive, and Dropbox to store and share files, but have you ever thought about the security risks? Once your files are uploaded, you’re relying on the service provider to keep them safe — and that may not be enough. That’s why encrypting your data before sending it to the cloud is a smart move. By doing this, even if someone manages to access your files, they won’t be able to open them without the decryption key.

The same principle applies to portable drives like USB sticks or external hard drives. If you lose your drive or someone steals it, your data could be exposed. However, with encryption (like using BitLocker on Windows), your files are protected by a password, so no one can get in.

Why You Should Encrypt Your Files

When you upload files to cloud services, they’re often encrypted — but here’s the catch: the service provider holds the encryption keys. This means if their servers are hacked, or if someone with access decides to peek at your files, they could. Encrypting files on your computer before you upload them ensures that only you hold the key to unlock them. It’s an extra step that gives you full control over your data.

Encrypting Drives with BitLocker

Portable drives are convenient but easy to lose, and they can contain sensitive information. BitLocker, a built-in tool for Windows, lets you encrypt an entire drive with a password, locking out anyone who tries to access it without your permission. Here’s how you can do it:

  1. Plug in your USB or external drive.
  2. Right-click the drive and select “Turn on BitLocker.” You can also manage BitLocker by entering it in windows search.
  3. Set a strong password (I recommend at least 12 characters for better security).
  4. Save your recovery key somewhere safe.
  5. Start the encryption process.

This way, if you lose the drive or it gets stolen, your data stays locked away.

Why Password Length Beats Complexity

When creating a password, you might think that mixing in symbols like @ and # makes it stronger. But in reality, the length of your password plays a bigger role in keeping it safe.

Here’s a simple way to think about it:

  • We have 26 uppercase letters (A-Z),
  • 26 lowercase letters (a-z),
  • 10 numbers (0–9),
  • and about 32 special characters (things like !@#$%^&*).

That means there are 94 possible characters to choose from for each spot in your password. The longer your password, the more it increases the number of possible combinations, making it harder to crack through brute-force or dictionary attacks.

Encrypting Folders with 7zip

Let’s say you have a folder of personal photos stored at /home/kali/photos and you want to encrypt them before uploading them anywhere. Here’s how you can do it using 7zip, a powerful tool for compressing and encrypting files:

7z a -t7z -p -mhe=on -mmt=48 -mx=9 /mnt/d/photos.7z /home/kali/photos

Now, let’s break that down:

  • 7z a: This command tells 7zip to create an archive (the a stands for "add").
  • -t7z: Specifies that the archive format should be 7z, which is a format that provides strong encryption and compression.
  • -p: This is where you’ll add a password for encryption. 7zip uses AES-256, which is one of the most secure encryption algorithms out there.
  • -mhe=on: This turns on header encryption, so not even the file names are visible without the password.
  • -mmt=48: This option sets the number of CPU threads used for compression. I have a machine with 48 threads, so I use all of them for faster performance.
  • -mx=9: This specifies the compression level. Level 9 is the highest and gives you the smallest file size but takes more time to process.
  • /mnt/d/photos.7z: This is the name of the encrypted archive.
  • /home/kali/photos: This is the folder you want to compress and encrypt.

After running this command, you’ll have a fully encrypted archive that you can safely store in the cloud.

At the end of the day, encrypting your files before sending them to a cloud service and encrypting portable drives is all about keeping your information safe. It’s an easy step that can save you from potential data leaks, hacks, or unwanted eyes. And remember — when it comes to passwords, longer is better {that’s what she said}. Whether you’re securing work files or personal memories, encryption gives you peace of mind, knowing your data is locked down.

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Digi
Digi

Written by Digi

Cybersecurity professional with 20+ years of experience as a PHP web developer and Linux server administrator. Enjoys CTF events to expand knowledge.

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