--- /dev/null
+\input texinfo @c -*-texinfo-*-
+
+@setfilename pgg.info
+
+@set VERSION 0.1
+
+@direntry
+* PGG: (pgg). Emacs interface to various PGP implementations.
+@end direntry
+
+@settitle PGG @value{VERSION}
+
+@ifinfo
+This file describes the PGG.
+
+Copyright (C) 2000 Daiki Ueno.
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.1 or
+any later version published by the Free Software Foundation; with no
+Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
+Texts. A copy of the license is included in the section entitled "GNU
+Free Documentation License".
+@end ifinfo
+
+@tex
+
+@titlepage
+@title PGG
+
+@author by Daiki Ueno
+@page
+
+@vskip 0pt plus 1filll
+Copyright @copyright{} 2000 Daiki Ueno.
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.1 or
+any later version published by the Free Software Foundation; with no
+Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
+Texts. A copy of the license is included in the section entitled "GNU
+Free Documentation License".
+@end titlepage
+@page
+
+@end tex
+
+@node Top
+@top PGG
+This manual describes PGG. PGG is an interface library between Emacs
+and various tools for secure communication. PGG also provides a simple
+user interface to encrypt, decrypt, sign, and verify MIME messages.
+
+@menu
+* Overview:: What PGG is.
+* Prerequisites::
+* How to use:: Calling PGP from your applications.
+* Architecture::
+* Parsing OpenPGP packets::
+* Function Index::
+* Variable Index::
+@end menu
+
+@node Overview
+@chapter Overview
+
+PGG is an interface library between Emacs and various tools for secure
+communication. Even though Mailcrypt has similar feature, it does not
+deal with detached PGP messages, normally used in PGP/MIME
+infrastructure. This was the main reason why I wrote the new library.
+
+PGP/MIME is an application of MIME Object Security Services (RFC1848).
+The standard is documented in RFC2015.
+
+@node Prerequisites
+@chapter Prerequisites
+
+PGG requires at least one implementation of privacy guard system.
+This document assumes that you have already obtained and installed them
+and that you are familiar with its basic functions.
+
+By default, PGG assumes to use GnuPG, but Pretty Good Privacy version 2
+or version 5 are also supported. If you are new to such a system, I
+recomend that you should look over the `GNU Privacy Handbook (GPH)',
+which is available at @uref{http://www.gnupg.org/gph/}.
+
+@node How to use
+@chapter How to use
+
+The toplevel interface of this library is still simple, and only
+intended to use with public-key cryptographic operation.
+
+To use PGG, please evaluate following expression at the beginning of
+your application program.
+
+@lisp
+(require 'pgg)
+@end lisp
+
+If you want to check existence of pgg.el at runtime, instead you can
+list autoload settings for functions you want as follows.
+
+@lisp
+(autoload 'pgg-encrypt-region "pgg"
+ "Encrypt the current region." t)
+(autoload 'pgg-decrypt-region "pgg"
+ "Decrypt the current region." t)
+(autoload 'pgg-sign-region "pgg"
+ "Sign the current region." t)
+(autoload 'pgg-verify-region "pgg"
+ "Verify the current region." t)
+(autoload 'pgg-insert-key "pgg"
+ "Insert the ASCII armored public key." t)
+(autoload 'pgg-snarf-keys-region "pgg"
+ "Import public keys in the current region." t)
+@end lisp
+
+@menu
+* User Commands::
+* Selecting an implementation::
+* Caching passphrase::
+@end menu
+
+@node User Commands
+@section User Commands
+
+At this time you can use various cryptographic commands. The behavior
+of these commands relies on the fashion of invocation because these
+commands are also intended to be used as library functions. For
+example, in case you don't have the signer's public key, the function
+`pgg-verify-region' fails immediately, but if the function had been
+called interactively, it would ask you to retrieve the signer's public
+key from the server.
+
+@deffn Command pgg-encrypt-region start end recipients
+Encrypt the current region between @var{start} and @var{end} for
+@var{recipients}. When the function were called interactively, you
+would be asked about the recipients.
+
+If encryption is successful, it replaces the current region contents (in
+the accessible portion) with the resulting data.
+@end deffn
+
+@deffn Command pgg-decrypt-region start end
+Decrypt the current region between @var{start} and @var{end}. If
+decryption is successful, it replaces the current region contents (in
+the accessible portion) with the resulting data.
+@end deffn
+
+@deffn Command pgg-sign-region start end &optional cleartext
+Make the signature from text between @var{start} and @var{end}. If the
+optional third argument @var{cleartext} is non-@code{nil}, or the
+function is called interactively, it does not create a detached
+signature. In such a case, it replaces the current region contents (in
+the accessible portion) with the resulting data.
+@end deffn
+
+@deffn Command pgg-verify-region start end &optional signature fetch
+Verify the current region between @var{start} and @var{end}. If the
+optional third argument @var{signature} is non-@code{nil}, or the function
+is called interactively, it is treated as the detached signature of the
+current region.
+
+If the optional 4th argument @var{fetch} is non-@code{nil}, or the
+function is called interactively, we attempt to fetch the signer's
+public key from the key server.
+@end deffn
+
+@deffn Command pgg-insert-key
+Retrieve the user's public key and insert it as ASCII-armored format.
+@end deffn
+
+@deffn Command pgg-snarf-keys-region start end
+Collect public keys in the current region between @var{start} and
+@var{end}, and add them into the user's keyring.
+@end deffn
+
+@node Selecting an implementation
+@section Selecting an implementation
+
+Since PGP has a long history and there are a number of PGP
+implementations available today, the function which each one has differs
+considerably. For example, if you are using GnuPG, you know you can
+select cipher algorithm from 3DES, CAST5, BLOWFISH, and so on, but on
+the other hand the version 2 of PGP only supports IDEA.
+
+By default, if the variable @var{pgg-scheme} is not set, PGG searches the
+registered scheme for an implementation of the requested service
+associated with the named algorithm. If there are no match, PGG uses
+@var{pgg-default-scheme}. In other words, there are two options to
+controll which command is used to process the incoming PGP armors. One
+is for encrypting and signing, the other is for decrypting and
+verifying.
+
+@defvar pgg-scheme
+Force specify the scheme of PGP implementation for decrypting and verifying.
+The value can be @code{gpg}, @code{pgp}, and @code{pgp5}.
+@end defvar
+
+@defvar pgg-default-scheme
+Force specify the scheme of PGP implementation for encrypting and signing.
+The value can be @code{gpg}, @code{pgp}, and @code{pgp5}.
+@end defvar
+
+@node Caching passphrase
+@section Caching passphrase
+
+PGG provides a simple passphrase caching mechanism. If you want to
+arrange the interaction, set the variable @var{pgg-read-passphrase}.
+
+@defvar pgg-cache-passphrase
+If non-@code{nil}, store passphrases. The default value of this
+variable is @code{t}. If you were worry about security issue, however,
+you could stop caching.
+@end defvar
+
+@defvar pgg-passphrase-cache-expiry
+The elapsed time for expiration in seconds.
+@end defvar
+
+@node Architecture
+@chapter Architecture
+
+PGG introduces the notion of a "scheme of PGP implementation" (used
+interchangeably with "scheme" in this document). This term refers to a
+singleton object wrapped with the luna object system.
+
+Since PGG was designed for accessing and developing PGP functionality,
+the architecture had to be designed not just for interoperablity but
+also for extensiblity. In this chapter we explore the architecture
+while finding out how to write the PGG backend.
+
+@menu
+* Initializing::
+* Backend methods::
+* Getting output::
+@end menu
+
+@node Initializing
+@section Initializing
+
+A scheme must be initialized before it is used.
+It had better guarantee to keep only one instance of a scheme.
+
+The following code is snipped out of @file{pgg-gpg.el}. Once an
+instance of @code{pgg-gpg} scheme is initialized, it's stored to the
+variable @var{pgg-scheme-gpg-instance} and will be reused from now on.
+
+@lisp
+(defvar pgg-scheme-gpg-instance nil)
+
+(defun pgg-make-scheme-gpg ()
+ (or pgg-scheme-gpg-instance
+ (setq pgg-scheme-gpg-instance
+ (luna-make-entity 'pgg-scheme-gpg))))
+@end lisp
+
+The name of the function must follow the
+regulation---@code{pgg-make-scheme-} follows the backend name.
+
+@node Backend methods
+@section Backend methods
+
+In each backend, these methods must be present. The output of these
+methods is stored in special buffers (@ref{Getting output}), so that
+these methods must tell the status of the execution.
+
+@deffn Method pgg-scheme-lookup-key scheme string &optional type
+Return keys associated with @var{string}. If the optional third
+argument @var{type} is non-@code{nil}, it searches from the secret
+keyrings.
+@end deffn
+
+@deffn Method pgg-scheme-encrypt-region scheme start end recipients
+Encrypt the current region between @var{start} and @var{end} for
+@var{recipients}. If encryption is successful, it returns @code{t},
+otherwise @code{nil}.
+@end deffn
+
+@deffn Method pgg-scheme-decrypt-region scheme start end
+Decrypt the current region between @var{start} and @var{end}. If
+decryption is successful, it returns @code{t}, otherwise @code{nil}.
+@end deffn
+
+@deffn Method pgg-scheme-sign-region scheme start end &optional cleartext
+Make the signature from text between @var{start} and @var{end}. If the
+optional third argument @var{cleartext} is non-@code{nil}, it does not
+create a detached signature. If signing is successful, it returns
+@code{t}, otherwise @code{nil}.
+@end deffn
+
+@deffn Method pgg-scheme-verify-region scheme start end &optional signature
+Verify the current region between @var{start} and @var{end}. If the
+optional third argument @var{signature} is non-@code{nil}, it is treated
+as the detached signature of the current region. If the signature is
+successflly verified, it returns @code{t}, otherwise @code{nil}.
+@end deffn
+
+@deffn Method pgg-scheme-insert-key scheme
+Retrieve the user's public key and insert it as ASCII-armored format.
+On success, it returns @code{t}, otherwise @code{nil}.
+@end deffn
+
+@deffn Method pgg-scheme-snarf-keys-region scheme start end
+Collect public keys in the current region between @var{start} and
+@var{end}, and add them into the user's keyring.
+On success, it returns @code{t}, otherwise @code{nil}.
+@end deffn
+
+@node Getting output
+@section Getting output
+
+The output of the backend methods (@ref{Backend methods}) is stored in
+special buffers, so that these methods must tell the status of the
+execution.
+
+@defvar pgg-errors-buffer
+The standard error output of the execution of the PGP command is stored
+here.
+@end defvar
+
+@defvar pgg-output-buffer
+The standard output of the execution of the PGP command is stored here.
+@end defvar
+
+@defvar pgg-status-buffer
+The rest of status information of the execution of the PGP command is
+stored here.
+@end defvar
+
+@node Parsing OpenPGP packets
+@chapter Parsing OpenPGP packets
+
+The format of OpenPGP messages is maintained in order to publish all
+necessary information needed to develop interoperable applications.
+The standard is documented in RFC 2440.
+
+PGG has its own parser for the OpenPGP packets.
+
+@defun pgg-parse-armor string
+List the sequence of packets in @var{string}.
+@end defun
+
+@defun pgg-parse-armor-region start end
+List the sequence of packets in the current region between @var{start}
+and @var{end}.
+@end defun
+
+@defvar pgg-ignore-packet-checksum
+If non-@code{nil}, don't check the checksum of the packets.
+@end defvar
+
+@node Function Index
+@chapter Function Index
+@printindex fn
+
+@node Variable Index
+@chapter Variable Index
+@printindex vr
+
+@summarycontents
+@contents
+@bye
+
+@c End:
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