I used the free software: GnuPG aka GPG. The gpg website (www.gnupg.org) can answer the rest of your questions better than I. I believe it depends on what algorithm (RSA, assymetric, etc) you are using. I think PGP has some encryption routines that the algorithm has not made its way into the public domain yet.

Richard


>Thanks richard,
>
> Did you use the free software of GPG? If we use GPG instead of PGP, how can it affect the client, Do he have to have GPG software too?
>
>Bharat