Update README.md

Improved the antivirus section. Clarified what this suggestion means, that the advice is to not use a free antivirus solution from a commercial vendor.
Also fixed a typo, calmAV to ClamAV.

README.md

@@ -336,7 +336,7 @@ Although Windows and OS X are easy to use and convenient, they both are far from
 **Protect Against Software Keyloggers** | Optional | A software keylogger is a malicious application running in the background that logs (and usually relays to a server) every key you press, aka all data that you type (passwords, emails, search terms, financial details etc). The best way to stay protected, is to keep your systems security settings enabled, and periodically check for rootkits- which will detect most loggers. Another option, is to use a key stroke encryption tool. For Windows there is [GhostPress](https://schiffer.tech/ghostpress.html), [Spy Shelter](https://www.spyshelter.com/) or [KeyScrambler](https://www.qfxsoftware.com) (developed by Qian Wang)  which encrypt your keystrokes at the keyboard driver level, and then decrypting them at the application level, meaning any software keylogger would just receive encrypted data.
 **Check Keyboard Connection** | Optional | Check your keyboards USB cable before using, bring your own keyboard to work and watch out for signs that it may have been tampered with. A hardware keylogger is a physical device that either sits between your keyboard and the USB connection into your PC, or is implanted into a keyboard. It intercepts and stores keystrokes, and in some cases can remotely upload them. Unlike a software logger, they can not be detected from your PC, but also they can not intercept data from virtual keyboards (like [OSK](https://support.microsoft.com/en-us/help/10762/windows-use-on-screen-keyboard)), clipboard or auto-fill password managers.
 **Prevent Keystroke Injection Attacks** | Optional | Always lock your PC when you step away from it (however this is not fool-proof, and [can be circumvented](https://www.youtube.com/watch?v=a4OyqaqFDW0)). For Linux, there is [USBGuard](https://github.com/USBGuard/usbguard), and for Windows there's [DuckHunt](https://github.com/pmsosa/duckhunt), which will detect super fast (badUSB-level super-fast) it will block input until the attack stops. Alternatively, Windows Group Policy can also be [configured to not trust new devices by default](https://www.itechtics.com/enable-gpedit-windows-10-home/). [Port Blockers](https://lindy.com/en/technology/port-blockers/) provide some level of physical protection, which may prevent an opportunistic attack, but can be circumvented fairly easily
-**Don't use Free Anti-Virus** | Optional | The included security tools, which come with bundled your operating system (such as Windows Defender), should be adequate at protecting against threats. Free anti-virus applications are often more of a hinder than a help- as they require admin permissions, full access to all data and settings, and internet access. They usually collect a lot of data, which is uploaded to the cloud and sometimes [sold to third-parties](https://www.forbes.com/sites/thomasbrewster/2019/12/09/are-you-one-of-avasts-400-million-users-this-is-why-it-collects-and-sells-your-web-habits/). Therefore, you should avoid programs such as Avast, AVG, Norton, Kasperky, Avira etc- even the paid plans come with privacy concerns. If you need a dedicated anti-virus application, consider [CalmAV](https://www.clamav.net/), which is open source. And for scanning 1-off files, [VirusTotal](https://www.virustotal.com/) is a useful tool
+**Don't use commercial "Free" Anti-Virus** | Optional | The included security tools, which come with bundled your operating system (such as Windows Defender), should be adequate at protecting against threats. Free anti-virus applications are often more of a hinder than a help- as they require admin permissions, full access to all data and settings, and internet access. They usually collect a lot of data, which is uploaded to the cloud and sometimes [sold to third-parties](https://www.forbes.com/sites/thomasbrewster/2019/12/09/are-you-one-of-avasts-400-million-users-this-is-why-it-collects-and-sells-your-web-habits/). Therefore, you should avoid non-libre closed source programs such as Avast, AVG, Norton, Kasperky, Avira etc- even the paid plans come with privacy concerns. If you need a dedicated anti-virus application, consider [ClamAV](https://www.clamav.net/), which is open source and libre meaning completely open. And for scanning 1-off files, [VirusTotal](https://www.virustotal.com/) is a useful tool
 **Periodically check for Rootkits** | Advanced | You should regularly check for rootkits (which may allow an attacker full control over your system), you can do this with a tool like [chkrootkit](http://www.chkrootkit.org/), once installed just run `sudo chkrootkit`. For Windows users, see [rootkit-revealer](https://docs.microsoft.com/en-us/sysinternals/downloads/rootkit-revealer) or [gmer](http://www.gmer.net/)
 **BIOS Boot Password** | Advanced | A BIOS or UEFI password once enabled, will need to be entered before the system can be booted, which may help to prevent an inexperienced hacker from getting into your OS, booting from a USB, tampering with BIOS as well as other actions. However, it can be easy to bypass, don't put too much trust in this - it should only be used as an additional step, to exhaust your adversaries resources a little faster. [Here is a guide on how to enable password](https://www.howtogeek.com/186235/how-to-secure-your-computer-with-a-bios-or-uefi-password/).
 **Use a Security-Focused Operating System** | Advanced | Microsoft, Apple and Google all have practices that violate users privacy, switching to Linux will mitigate most of these issues. For more advanced users, consider a security-focused distro- such as [QubeOS](https://www.qubes-os.org/), which allows for compartmentalization of applications and data, and has strong encryption and Tor networking build in. For some actions, [Tails](https://tails.boum.org/) a live operating system with no memory persistence is as close as you can get to not leaving a data trail on your system. BSD is also great for security, see [FreeBSD](https://www.freebsd.org/) and [OpenBSD](https://www.openbsd.org/). Even a general purpose distro, will be much better for privacy compared to a propriety counterpart: [Fedora](https://getfedora.org/), [Debian](https://www.debian.org/), [Arch](https://www.archlinux.org/) / [Manjaro](https://manjaro.org/), [see more](/5_Privacy_Respecting_Software.md#pc-operating-systems)