Hot answers tagged digital-signature
There already exists a standard for signing and encrypting emails call S/MIME. It's supported by most OS native email clients (and gmail with help). Both the sender and receiver have to have each other's public cert for encryption (this public cert is sent with all signed emailed). Only the sender needs a cert to allow for simple non-encrypted email ...
For LinkedIn, complete instructions are on page Creating, Editing or Saving Your LinkedIn Email Signature. It contains a link that connects to your create Create Email Signature profile page. Please make sure you are logged into your LinkedIn account before clicking on the Create Email Signature page link.
I believe this firefox extension may do what you require: https://addons.mozilla.org/en-US/firefox/addon/592/
Hushmail offers end-to-end encrypted & signed PGP email. You can optionally use the Java applet, which ensures that the encryption takes place on your computer. Otherwise the PGP encryption takes place on our servers. Links to further info: Hushmail - Main page Hushmail - Security page Wikipedia entry
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