def encrypt from, to, payload, sign=false
payload_fn = Tempfile.new "redwood.payload"
payload_fn.write format_payload(payload)
payload_fn.close
encrypted_fn = Tempfile.new "redwood.encrypted"; encrypted_fn.close
recipient_opts = (to + [ from ] ).map { |r| "--recipient '<#{r}>'" }.join(" ")
sign_opts = sign ? "--sign --local-user '#{from}'" : ""
message = run_gpg "--output #{encrypted_fn.path} --yes --armor --encrypt --textmode #{sign_opts} #{recipient_opts} #{payload_fn.path}", :interactive => true
unless $?.success?
info "Error while running gpg: #{message}"
raise Error, "GPG command failed. See log for details."
end
encrypted_payload = RMail::Message.new
encrypted_payload.header["Content-Type"] = "application/octet-stream"
encrypted_payload.header["Content-Disposition"] = 'inline; filename="msg.asc"'
encrypted_payload.body = IO.read(encrypted_fn.path)
control = RMail::Message.new
control.header["Content-Type"] = "application/pgp-encrypted"
control.header["Content-Disposition"] = "attachment"
control.body = "Version: 1\n"
envelope = RMail::Message.new
envelope.header["Content-Type"] = 'multipart/encrypted; protocol="application/pgp-encrypted"'
envelope.add_part control
envelope.add_part encrypted_payload
envelope
end