re[2]: Encrypting a file for anyone to read if having my public key.

[Alex Watson]

 My public key is not being made available en masse, but only to a select few =
individuals where it is imported to their key ring automatically.   The users =
don't typically interact directly with the software and encrypting/decrypting =
is done automatically.    So even though my public key is involved, it isn't =
being made available to a large group and users aren't intended to be involved =
directly in the encryption/decryption process.

 My dilemma is that I want some form of encryption, weak as it may be, to =
initially distribute software to these sites.   Then upon subsequent =
correspondence, I will receive a public key for these people after their =
software is installed and a keypair established.   I will then be able to =
encrypt specifically for them using their public key.

  Thus, I'd like some simple means by which to encrypt for use upon initial =
installation, which does not necessarily have to be strong, I'd like to have =
something more than nothing though.  I understand the weakness of such a =
method, but thought I had read about it somewhere.

  Actually, I could use conventional encryption using a password and that would =
be about equal in strength.  e.g.

gpg --output test.gpg --symmetric test.txt
Above works, but is interactive, have to enter passphrase, then retype it again

Is there something more like below which will work in an automated fashion?  =
(this doesn't work)
type pass.txt|gpg --output test.gpg --symmetric --passphrase-fd 0 test.txt

Where pass.txt holds the passphrase I want to encrypt with.

Thanks,
Alex