[Enigmail] Enignmail begginner

[Robert J. Hansen]

Rubén Ortiz wrote:
> my name is Ruben, and its my first email to the mailing list.

Welcome, Ruben!  :)

> But I have not any friend or aquintance who uses Enigmail or
> GPG encryption. So I can't  test it or really use it.

You can always test it by sending an encrypted, signed, or encrypted and
signed email to yourself.

> My question is: If the reciever doesn't have enigmail and I send an
> encrypted mail to him, what will happen?

You can only send an encrypted email to someone for whom you have a key.
 (There are ways around this, but generally it's true.)  So if you're
able to send an encrypted email to someone, they'll be able to read it,
regardless of whether they have Enigmail installed.  (For instance,
Enigmail interoperates very well with PGP Corporation's mail proxy.)

> My second question: it makes sense to sign one mail and no encrypte it?

It depends on the circumstances.  Most of the time it doesn't make
sense.  Some of the time it makes a lot of sense.  :)  If done properly
(which is enough material for a long email in and of itself), a signed
message is the equivalent of an ink signature on a paper contract: it's
legally binding and can be used for all different kinds of business.

As an example, if I'm doing freelance work for someone in another city,
I could send them an invoice via mail... and wait a week for it to
arrive, and then a week for their check to come back to me, and then a
week for the check to clear my bank.

Or, _assuming we did it right_, I could send a signed invoice.  That
signed invoice is a legally binding affidavit that I performed the
desired work.  It arrives at my client's inbox within seconds.  My
client reviews the invoice and writes a message to his bank, "Please pay
Mr. Hansen $X from my account."  My client signs the message.  I send
his bank a message, "Please route the payment with this routing number
to this bank account", again signed.  The result is that I send two
emails, my client sends one, and I could potentially get paid within a
minute.

Digital signatures have a lot of promise.  They have the potential to
make our lives a lot easier.  The problem is doing them right.