add security token

README.md

@@ -11,3 +11,4 @@ Kickstarter page: [kickstarter.com](https://www.kickstarter.com/projects/flipper
 * [Sub-1 GHz radio](wiki/sub-1ghz-radio.md)
 * [125 kHz RFID](wiki/125khz-rfid.md)
 * [iButton contact keys](wiki/ibutton.md)
+* [U2F/FIDO2 security token](wiki/security-token.md)

wiki/security-token.md

@@ -0,0 +1,7 @@
+# Security token
+
+Flipper Zero can act as a fully functional U2F key, that works with any U2F-enabled services such as Google, Twitter, Facebook, Dropbox, LastPass, Amazon AWS, and many others.
+
+Universal 2nd Factor (U2F) protocol is an open standard for hardware security tokens used for secure authentication. Developed by Google, Yubico, and NXP, U2F acts as a universal key that is designed to add another layer to the traditional login+password authentication method.
+
+Even if your password gets compromised, an attacker will not be able to log in to your account. This method is much stronger than the usual SMS 2nd-factor method, as it doesn’t involve any third-parties like a cell phone operator.