Email Encryption: Keep Private Key Safe

README.md

@@ -142,6 +142,7 @@ The big companies providing "free" email service, don't have a good reputation f
 **Don’t connect third-party apps to your email account** | Optional | If you give a third-party app or plug-in (such as Unroll.me, Boomerang, SaneBox etc) full access to your inbox, they effectively have full unhindered access to all your emails and their contents, which poses [significant security and privacy risks](https://zeltser.com/risks-of-email-search-services/)
 **Don't Share Sensitive Data via Email** | Optional | Emails are very easily intercepted. Further to this you can’t be sure of how secure your recipient's environment is. Therefore emails cannot be considered safe for exchanging confidential or personal information, unless it is encrypted/ or both parties are using a secure mail provider
 **Consider Switching to a Secure Mail Provider** | Optional | Secure and reputable email providers such as  [ProtonMail](https://protonmail.com) and [Tutanota](https://tutanota.com) allow for end-to-end encryption, full privacy as well as more security-focused features. Unlike typical email providers, your mailbox cannot be read by anyone but you, since all messages are encrypted. Providers such as Google, Microsoft and Yahoo scan messages for advertising, analytics and law enforcement purposes, but this poses a serious security threat
+**Use Smart Key** | Advanced | OpenPGP also [does not support](https://www.eff.org/deeplinks/2013/08/pushing-perfect-forward-secrecy-important-web-privacy-protection) Forward secrecy, which means if either your or the recipient's private key is ever stolen, all previous messages encrypted with it will be exposed. Therefore, you should take great care to keep your private keys safe. One method of doing so, is to use a USB Smart Key to sign or decrypt messages, allowing you to do so without your private key leaving the USB device.  Devices which support this include [NitroKey](https://www.nitrokey.com/), [YubiKey 5](https://www.yubico.com/products/yubikey-5-overview/) (See [Yubico Neo](https://developers.yubico.com/ykneo-openpgp/)), [Smart Card](https://www.floss-shop.de/en/security-privacy/smartcards/13/openpgp-smart-card-v3.3) (See [guide](https://spin.atomicobject.com/2014/02/09/gnupg-openpgp-smartcard/)), [OnlyKey](https://onlykey.io/)
 **Use Aliasing / Anonymous Forwarding** | Advanced | Email aliasing allows messages to be sent to [anything]@my-domain.com and still land in your primary inbox. Effectively allowing you to use a different, unique email address for each service you sign up for. This means if you start receiving spam, you can block that alias and determine which company leaked your email address. More importantly, you do not need to reveal your real email address to any company. <br>[Anonaddy](https://anonaddy.com) and [SimpleLogin](https://simplelogin.io/?slref=bridsqrgvrnavso) are open source anonymous email forwarding service allowing you to create unlimited email aliases, with a free plan
 **Subaddressing** | Optional | An alternative to aliasing is [subaddressing](https://en.wikipedia.org/wiki/Email_address#Subaddressing), where anything after the `+` symbol is omitted during mail delivery, for example you the address yourname+tag@example.com denotes the same delivery address as yourname@example.com. This was defined in [RCF-5233](https://tools.ietf.org/html/rfc5233), and supported by most major mail providers (inc Gmail, YahooMail, Outlook, FastMail and ProtonMail). It enables you to keep track of who shared/ leaked your email address, but unlike aliasing it will not protect against your real address being revealed
 **Use a Custom Domain** | Advanced | Using a custom domain, means that even you are not dependent on the address assigned my your mail provider. So you can easily switch providers in the future and do not need to worry about a service being discontinued