- Advanced encryption using the .7z format with AES-256 algorithm for maximum security.
- Importance of updating to version 26.03 to mitigate critical code execution vulnerabilities.
- Enabling the Propagate Zone.Id flow option to prevent bypassing the Windows SmartScreen filter.
When handling confidential data on a computer shared with others, on a company server, or even when sending it by email, the same question always arises: how do we prevent snoopers or unauthorized individuals from accessing our information? The most effective and accessible solution is to use compressed and encrypted files , with the .7z format being one of the most powerful standards for achieving this goal.
Although Windows and Mac come with their own compression tools, they fall short in terms of security. Therefore, installing external software like 7-Zip is highly recommended. This utility is not only free and compatible with almost any format, but it also offers robust data encryption , allowing you to easily and efficiently keep your documents secure.
Step-by-step guide to encrypting your folders and files
If you want to password-protect a folder so no one can access it, the process is quite intuitive. First, download the installer from the official website 7-zip.org (make sure to choose the x64 version for modern systems) and run it, following the steps to securely install software on your PC . Once installed, you'll see that 7-Zip integrates directly into the Windows Explorer context menu , making things much easier.
To protect your content, right-click on the folder or file, expand the "7-Zip" option, and choose "Add to archive…". In the settings window, you can adjust the location of the new archive, the compression level, and, most importantly, the encryption method . Here are a couple of key options:
- .7z format with AES-256: It's the most secure and powerful option. If you're looking for maximum confidentiality, always choose 256-bit AES.
- .zip format with ZipCrypto: It is less secure, but it has the advantage that the recipient can open the file in Windows without needing to have any external program installed.
A crucial detail is to check the "Encrypt file names" box . If you don't, anyone will be able to see the names of the documents inside, even if they can't open them. Once everything is configured, enter a password. Remember that the encryption is symmetric, meaning you'll use the same key to both lock and unlock the file, so the strength of your password will directly determine the security of your data.
Golden tips for real security
Using strong encryption is useless if the password is "123456". For effective protection, use long passwords with special characters and numbers. Furthermore, there's a golden rule in cybersecurity: never send the file and the password in the same email . Ideally, send the compressed file by email and communicate the password verbally, either by phone or SMS, to prevent an attacker who intercepts the email from obtaining the complete password.
Security alert: Current vulnerabilities and risks
Despite being a reliable tool, 7-Zip is not immune to flaws. Critical vulnerabilities have recently been discovered that could allow a malicious actor to execute malicious code on your PC. For example, the flaws registered as CVE-2025-11001 and CVE-2025-11002 affect the handling of symbolic links in ZIP files, allowing an attacker to access restricted directories. These flaws were present as early as version 21.02 and were fixed in version 25.0.
Another serious problem is its relationship with the Windows SmartScreen filter. By default, some versions of 7-Zip did not retain the Internet source label (known as Mark of the Web ) when extracting files. This meant that Windows Defender failed to warn the user about the dangers of a downloaded executable, bypassing a vital layer of protection. Vulnerabilities such as CVE-2025-0411 and CVE-2026-58052 (the latter related to RAR5 files) have forced the release of urgent patches.
How to secure your computer and keep your software up to date
To prevent your device from being vulnerable, the most urgent step is to update 7-Zip to version 26.03 or higher . This update not only closes the RAR5 file vulnerabilities and nested archives, but also fixes the CVE-2025-55188 vulnerability. It is vital to always perform this process from the official developer website , avoiding third-party sites that may have modified the installer to include malware.
In addition to updating, we recommend going to the program's options menu and finding the setting called "Propagate Stream Zone.Id" . Change the value from "No" to "Yes". This way, any file you extract from a compressed file downloaded from the internet will retain its source tag, allowing SmartScreen to assess the file's reputation before running it and warn you if there are any risks.
Keeping your software up to date and properly configuring security options is the only way to enjoy the benefits of compression without compromising your privacy. Ensuring you use strong passwords , updating your program to the latest version, and enabling zone stream propagation guarantees that your sensitive documents are truly safe and that your operating system can detect any external threats before they become undetectable.