This is a mechanism whereby an email or a Word document (also Acrobat) can be digitally signed to ensure it has not changed since signed, that it truly comes from the signer, and has a clear time stamp associated with it. A Imperial College digital certificate is automatically issued to you when you log in.
To send a signed (i.e. trusted) email, open up Outlook 2007 and from Tools/Trust Centre/E-mail security check the Add digital signature to outgoing messages button. You need only do this once, and all subsequent emails will be signed.
Whilst you are in this panel, also check that the Settings box is populated with an entry (this should happen automatically). If this box is empty, see if pressing the settings button allows you to get a certificate (be warned, this process can take up to 90 seconds).
Next, click on Publish to GAL. This publishes your certificate so that others can find it (they would need your certificate if they wish to send you an encrypted (as opposed to signed) email. It make take up to 30 minutes for your certificate to become searchable.
When you compose a new message, a Sign button will appear in the taskbar (on the far right hand side, red circle, right) which you can select/deselect as appropriate.
Search for other people's certificates here. If you have in your possesion your own certificate and another person's certificate (the public key thereof) you can go one step further than signing, and proceed to encrypting either the email, or the document, or both. Only you and the person whose certificate you have included will be able to read the resulting email/document.
An alternative to using Outlook is the Web interface (using Internet Explorer and URL: https://icex.imperial.ac.uk/Exchange/ ). Go to Options and thence E-Mail Security. You will be asked to download an S/MIME control. If you are using your own machine, you can install this. Currently, this installation is not possible on College machines (but watch this space).
Signing a Word Document
To sign a word document, create it, then from The top left icon, Prepare/Add a digital Signature. Follow the instructions (which include specifying a purpose for signing the document). Close the panels and save the document. You need to do this for each document you wish to sign.
Yo can combine the two operations, i.e. sign a document and then sign the email you use to send it to someone. You may be asked to use this combination when submitting course work to laboratory supervisors.
