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517 lines
16 KiB
EmacsLisp
517 lines
16 KiB
EmacsLisp
;;; pgg-parse.el --- OpenPGP packet parsing
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;; Copyright (C) 1999, 2002, 2003, 2004, 2005,
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;; 2006 Free Software Foundation, Inc.
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;; Author: Daiki Ueno <ueno@unixuser.org>
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;; Created: 1999/10/28
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;; Keywords: PGP, OpenPGP, GnuPG
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2, or (at your option)
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;; any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to the
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;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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;; Boston, MA 02110-1301, USA.
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;;; Commentary:
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;; This module is based on
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;; [OpenPGP] RFC 2440: "OpenPGP Message Format"
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;; by John W. Noerenberg, II <jwn2@qualcomm.com>,
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;; Jon Callas <jon@pgp.com>, Lutz Donnerhacke <lutz@iks-jena.de>,
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;; Hal Finney <hal@pgp.com> and Rodney Thayer <rodney@unitran.com>
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;; (1998/11)
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;;; Code:
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(eval-when-compile (require 'cl))
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(defgroup pgg-parse ()
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"OpenPGP packet parsing."
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:group 'pgg)
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(defcustom pgg-parse-public-key-algorithm-alist
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'((1 . RSA) (2 . RSA-E) (3 . RSA-S) (16 . ELG-E) (17 . DSA) (20 . ELG))
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"Alist of the assigned number to the public key algorithm."
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:group 'pgg-parse
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:type '(repeat
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(cons (sexp :tag "Number") (sexp :tag "Type"))))
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(defcustom pgg-parse-symmetric-key-algorithm-alist
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'((1 . IDEA) (2 . 3DES) (4 . CAST5) (5 . SAFER-SK128))
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"Alist of the assigned number to the simmetric key algorithm."
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:group 'pgg-parse
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:type '(repeat
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(cons (sexp :tag "Number") (sexp :tag "Type"))))
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(defcustom pgg-parse-hash-algorithm-alist
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'((1 . MD5) (2 . SHA1) (3 . RIPEMD160) (5 . MD2) (8 . SHA256) (9 . SHA384)
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(10 . SHA512))
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"Alist of the assigned number to the cryptographic hash algorithm."
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:group 'pgg-parse
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:type '(repeat
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(cons (sexp :tag "Number") (sexp :tag "Type"))))
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(defcustom pgg-parse-compression-algorithm-alist
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'((0 . nil); Uncompressed
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(1 . ZIP)
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(2 . ZLIB))
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"Alist of the assigned number to the compression algorithm."
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:group 'pgg-parse
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:type '(repeat
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(cons (sexp :tag "Number") (sexp :tag "Type"))))
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(defcustom pgg-parse-signature-type-alist
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'((0 . "Signature of a binary document")
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(1 . "Signature of a canonical text document")
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(2 . "Standalone signature")
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(16 . "Generic certification of a User ID and Public Key packet")
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(17 . "Persona certification of a User ID and Public Key packet")
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(18 . "Casual certification of a User ID and Public Key packet")
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(19 . "Positive certification of a User ID and Public Key packet")
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(24 . "Subkey Binding Signature")
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(31 . "Signature directly on a key")
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(32 . "Key revocation signature")
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(40 . "Subkey revocation signature")
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(48 . "Certification revocation signature")
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(64 . "Timestamp signature."))
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"Alist of the assigned number to the signature type."
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:group 'pgg-parse
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:type '(repeat
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(cons (sexp :tag "Number") (sexp :tag "Type"))))
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(defcustom pgg-ignore-packet-checksum t; XXX
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"If non-nil checksum of each ascii armored packet will be ignored."
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:group 'pgg-parse
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:type 'boolean)
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(defvar pgg-armor-header-lines
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'("^-----BEGIN PGP MESSAGE\\(, PART [0-9]+\\(/[0-9]+\\)?\\)?-----\r?$"
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"^-----BEGIN PGP PUBLIC KEY BLOCK-----\r?$"
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"^-----BEGIN PGP PRIVATE KEY BLOCK-----\r?$"
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"^-----BEGIN PGP SIGNATURE-----\r?$")
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"Armor headers.")
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(eval-and-compile
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(defalias 'pgg-char-int (if (fboundp 'char-int)
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'char-int
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'identity)))
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(defmacro pgg-format-key-identifier (string)
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`(mapconcat (lambda (c) (format "%02X" (pgg-char-int c)))
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,string "")
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;; `(upcase (apply #'format "%02x%02x%02x%02x%02x%02x%02x%02x"
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;; (string-to-number-list ,string)))
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)
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(defmacro pgg-parse-time-field (bytes)
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`(list (logior (lsh (car ,bytes) 8)
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(nth 1 ,bytes))
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(logior (lsh (nth 2 ,bytes) 8)
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(nth 3 ,bytes))
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0))
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(defmacro pgg-byte-after (&optional pos)
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`(pgg-char-int (char-after ,(or pos `(point)))))
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(defmacro pgg-read-byte ()
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`(pgg-char-int (char-after (prog1 (point) (forward-char)))))
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(defmacro pgg-read-bytes-string (nbytes)
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`(buffer-substring
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(point) (prog1 (+ ,nbytes (point))
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(forward-char ,nbytes))))
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(defmacro pgg-read-bytes (nbytes)
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`(mapcar #'pgg-char-int (pgg-read-bytes-string ,nbytes))
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;; `(string-to-number-list (pgg-read-bytes-string ,nbytes))
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)
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(defmacro pgg-read-body-string (ptag)
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`(if (nth 1 ,ptag)
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(pgg-read-bytes-string (nth 1 ,ptag))
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(pgg-read-bytes-string (- (point-max) (point)))))
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(defmacro pgg-read-body (ptag)
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`(mapcar #'pgg-char-int (pgg-read-body-string ,ptag))
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;; `(string-to-number-list (pgg-read-body-string ,ptag))
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)
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(defalias 'pgg-skip-bytes 'forward-char)
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(defmacro pgg-skip-header (ptag)
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`(pgg-skip-bytes (nth 2 ,ptag)))
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(defmacro pgg-skip-body (ptag)
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`(pgg-skip-bytes (nth 1 ,ptag)))
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(defmacro pgg-set-alist (alist key value)
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`(setq ,alist (nconc ,alist (list (cons ,key ,value)))))
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(when (fboundp 'define-ccl-program)
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(define-ccl-program pgg-parse-crc24
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'(1
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((loop
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(read r0) (r1 ^= r0) (r2 ^= 0)
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(r5 = 0)
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(loop
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(r1 <<= 1)
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(r1 += ((r2 >> 15) & 1))
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(r2 <<= 1)
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(if (r1 & 256)
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((r1 ^= 390) (r2 ^= 19707)))
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(if (r5 < 7)
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((r5 += 1)
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(repeat))))
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(repeat)))))
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(defun pgg-parse-crc24-string (string)
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(let ((h (vector nil 183 1230 nil nil nil nil nil nil)))
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(ccl-execute-on-string pgg-parse-crc24 h string)
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(format "%c%c%c"
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(logand (aref h 1) 255)
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(logand (lsh (aref h 2) -8) 255)
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(logand (aref h 2) 255)))))
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(defmacro pgg-parse-length-type (c)
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`(cond
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((< ,c 192) (cons ,c 1))
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((< ,c 224)
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(cons (+ (lsh (- ,c 192) 8)
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(pgg-byte-after (+ 2 (point)))
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192)
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2))
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((= ,c 255)
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(cons (cons (logior (lsh (pgg-byte-after (+ 2 (point))) 8)
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(pgg-byte-after (+ 3 (point))))
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(logior (lsh (pgg-byte-after (+ 4 (point))) 8)
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(pgg-byte-after (+ 5 (point)))))
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5))
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(t;partial body length
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'(0 . 0))))
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(defun pgg-parse-packet-header ()
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(let ((ptag (pgg-byte-after))
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length-type content-tag packet-bytes header-bytes)
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(if (zerop (logand 64 ptag));Old format
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(progn
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(setq length-type (logand ptag 3)
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length-type (if (= 3 length-type) 0 (lsh 1 length-type))
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content-tag (logand 15 (lsh ptag -2))
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packet-bytes 0
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header-bytes (1+ length-type))
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(dotimes (i length-type)
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(setq packet-bytes
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(logior (lsh packet-bytes 8)
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(pgg-byte-after (+ 1 i (point)))))))
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(setq content-tag (logand 63 ptag)
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length-type (pgg-parse-length-type
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(pgg-byte-after (1+ (point))))
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packet-bytes (car length-type)
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header-bytes (1+ (cdr length-type))))
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(list content-tag packet-bytes header-bytes)))
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(defun pgg-parse-packet (ptag)
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(case (car ptag)
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(1 ;Public-Key Encrypted Session Key Packet
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(pgg-parse-public-key-encrypted-session-key-packet ptag))
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(2 ;Signature Packet
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(pgg-parse-signature-packet ptag))
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(3 ;Symmetric-Key Encrypted Session Key Packet
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(pgg-parse-symmetric-key-encrypted-session-key-packet ptag))
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;; 4 -- One-Pass Signature Packet
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;; 5 -- Secret Key Packet
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(6 ;Public Key Packet
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(pgg-parse-public-key-packet ptag))
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;; 7 -- Secret Subkey Packet
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;; 8 -- Compressed Data Packet
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(9 ;Symmetrically Encrypted Data Packet
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(pgg-read-body-string ptag))
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(10 ;Marker Packet
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(pgg-read-body-string ptag))
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(11 ;Literal Data Packet
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(pgg-read-body-string ptag))
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;; 12 -- Trust Packet
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(13 ;User ID Packet
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(pgg-read-body-string ptag))
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;; 14 -- Public Subkey Packet
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;; 60 .. 63 -- Private or Experimental Values
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))
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(defun pgg-parse-packets (&optional header-parser body-parser)
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(let ((header-parser
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(or header-parser
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(function pgg-parse-packet-header)))
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(body-parser
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(or body-parser
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(function pgg-parse-packet)))
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result ptag)
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(while (> (point-max) (1+ (point)))
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(setq ptag (funcall header-parser))
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(pgg-skip-header ptag)
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(push (cons (car ptag)
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(save-excursion
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(funcall body-parser ptag)))
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result)
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(if (zerop (nth 1 ptag))
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(goto-char (point-max))
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(forward-char (nth 1 ptag))))
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result))
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(defun pgg-parse-signature-subpacket-header ()
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(let ((length-type (pgg-parse-length-type (pgg-byte-after))))
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(list (pgg-byte-after (+ (cdr length-type) (point)))
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(1- (car length-type))
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(1+ (cdr length-type)))))
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(defun pgg-parse-signature-subpacket (ptag)
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(case (car ptag)
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(2 ;signature creation time
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(cons 'creation-time
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(let ((bytes (pgg-read-bytes 4)))
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(pgg-parse-time-field bytes))))
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(3 ;signature expiration time
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(cons 'signature-expiry
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(let ((bytes (pgg-read-bytes 4)))
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(pgg-parse-time-field bytes))))
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(4 ;exportable certification
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(cons 'exportability (pgg-read-byte)))
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(5 ;trust signature
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(cons 'trust-level (pgg-read-byte)))
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(6 ;regular expression
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(cons 'regular-expression
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(pgg-read-body-string ptag)))
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(7 ;revocable
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(cons 'revocability (pgg-read-byte)))
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(9 ;key expiration time
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(cons 'key-expiry
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(let ((bytes (pgg-read-bytes 4)))
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(pgg-parse-time-field bytes))))
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;; 10 = placeholder for backward compatibility
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(11 ;preferred symmetric algorithms
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(cons 'preferred-symmetric-key-algorithm
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(cdr (assq (pgg-read-byte)
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pgg-parse-symmetric-key-algorithm-alist))))
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(12 ;revocation key
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)
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(16 ;issuer key ID
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(cons 'key-identifier
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(pgg-format-key-identifier (pgg-read-body-string ptag))))
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(20 ;notation data
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(pgg-skip-bytes 4)
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(cons 'notation
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(let ((name-bytes (pgg-read-bytes 2))
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(value-bytes (pgg-read-bytes 2)))
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(cons (pgg-read-bytes-string
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(logior (lsh (car name-bytes) 8)
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(nth 1 name-bytes)))
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(pgg-read-bytes-string
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(logior (lsh (car value-bytes) 8)
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(nth 1 value-bytes)))))))
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(21 ;preferred hash algorithms
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(cons 'preferred-hash-algorithm
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(cdr (assq (pgg-read-byte)
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pgg-parse-hash-algorithm-alist))))
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(22 ;preferred compression algorithms
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(cons 'preferred-compression-algorithm
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(cdr (assq (pgg-read-byte)
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pgg-parse-compression-algorithm-alist))))
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(23 ;key server preferences
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(cons 'key-server-preferences
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(pgg-read-body ptag)))
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(24 ;preferred key server
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(cons 'preferred-key-server
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(pgg-read-body-string ptag)))
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;; 25 = primary user id
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(26 ;policy URL
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(cons 'policy-url (pgg-read-body-string ptag)))
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;; 27 = key flags
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;; 28 = signer's user id
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;; 29 = reason for revocation
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;; 100 to 110 = internal or user-defined
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))
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(defun pgg-parse-signature-packet (ptag)
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(let* ((signature-version (pgg-byte-after))
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(result (list (cons 'version signature-version)))
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hashed-material field n)
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(cond
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((= signature-version 3)
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(pgg-skip-bytes 2)
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(setq hashed-material (pgg-read-bytes 5))
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(pgg-set-alist result
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'signature-type
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(cdr (assq (pop hashed-material)
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pgg-parse-signature-type-alist)))
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(pgg-set-alist result
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'creation-time
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(pgg-parse-time-field hashed-material))
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(pgg-set-alist result
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'key-identifier
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(pgg-format-key-identifier
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(pgg-read-bytes-string 8)))
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(pgg-set-alist result
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'public-key-algorithm (pgg-read-byte))
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(pgg-set-alist result
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'hash-algorithm (pgg-read-byte)))
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((= signature-version 4)
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(pgg-skip-bytes 1)
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(pgg-set-alist result
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'signature-type
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(cdr (assq (pgg-read-byte)
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pgg-parse-signature-type-alist)))
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(pgg-set-alist result
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'public-key-algorithm
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(pgg-read-byte))
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(pgg-set-alist result
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'hash-algorithm (pgg-read-byte))
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(when (>= 10000 (setq n (pgg-read-bytes 2)
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n (logior (lsh (car n) 8)
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(nth 1 n))))
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(save-restriction
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(narrow-to-region (point)(+ n (point)))
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(nconc result
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(mapcar (function cdr) ;remove packet types
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(pgg-parse-packets
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#'pgg-parse-signature-subpacket-header
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#'pgg-parse-signature-subpacket)))
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(goto-char (point-max))))
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(when (>= 10000 (setq n (pgg-read-bytes 2)
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n (logior (lsh (car n) 8)
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(nth 1 n))))
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(save-restriction
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(narrow-to-region (point)(+ n (point)))
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(nconc result
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(mapcar (function cdr) ;remove packet types
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(pgg-parse-packets
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#'pgg-parse-signature-subpacket-header
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#'pgg-parse-signature-subpacket)))))))
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(setcdr (setq field (assq 'public-key-algorithm
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result))
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(cdr (assq (cdr field)
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pgg-parse-public-key-algorithm-alist)))
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(setcdr (setq field (assq 'hash-algorithm
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result))
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(cdr (assq (cdr field)
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pgg-parse-hash-algorithm-alist)))
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result))
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(defun pgg-parse-public-key-encrypted-session-key-packet (ptag)
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(let (result)
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(pgg-set-alist result
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'version (pgg-read-byte))
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(pgg-set-alist result
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'key-identifier
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(pgg-format-key-identifier
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(pgg-read-bytes-string 8)))
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(pgg-set-alist result
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'public-key-algorithm
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(cdr (assq (pgg-read-byte)
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pgg-parse-public-key-algorithm-alist)))
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result))
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(defun pgg-parse-symmetric-key-encrypted-session-key-packet (ptag)
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(let (result)
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(pgg-set-alist result
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'version
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(pgg-read-byte))
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(pgg-set-alist result
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'symmetric-key-algorithm
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(cdr (assq (pgg-read-byte)
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pgg-parse-symmetric-key-algorithm-alist)))
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result))
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(defun pgg-parse-public-key-packet (ptag)
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(let* ((key-version (pgg-read-byte))
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(result (list (cons 'version key-version)))
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field)
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(cond
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((= 3 key-version)
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(pgg-set-alist result
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'creation-time
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(let ((bytes (pgg-read-bytes 4)))
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(pgg-parse-time-field bytes)))
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(pgg-set-alist result
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'key-expiry (pgg-read-bytes 2))
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(pgg-set-alist result
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'public-key-algorithm (pgg-read-byte)))
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((= 4 key-version)
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(pgg-set-alist result
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'creation-time
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(let ((bytes (pgg-read-bytes 4)))
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(pgg-parse-time-field bytes)))
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(pgg-set-alist result
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'public-key-algorithm (pgg-read-byte))))
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(setcdr (setq field (assq 'public-key-algorithm
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result))
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(cdr (assq (cdr field)
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pgg-parse-public-key-algorithm-alist)))
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result))
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(defun pgg-decode-packets ()
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(if (re-search-forward "^=\\([A-Za-z0-9+/]\\{4\\}\\)$" nil t)
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(let ((p (match-beginning 0))
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(checksum (match-string 1)))
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(delete-region p (point-max))
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|
(if (ignore-errors (base64-decode-region (point-min) p))
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|
(or (not (fboundp 'pgg-parse-crc24-string))
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|
pgg-ignore-packet-checksum
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|
(string-equal (base64-encode-string (pgg-parse-crc24-string
|
|
(buffer-string)))
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|
checksum)
|
|
(progn
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|
(message "PGP packet checksum does not match")
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|
nil))
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|
(message "PGP packet contain invalid base64")
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|
nil))
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|
(message "PGP packet checksum not found")
|
|
nil))
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|
|
|
(defun pgg-decode-armor-region (start end)
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|
(save-restriction
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|
(narrow-to-region start end)
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|
(goto-char (point-min))
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|
(re-search-forward "^-+BEGIN PGP" nil t)
|
|
(delete-region (point-min)
|
|
(and (search-forward "\n\n")
|
|
(match-end 0)))
|
|
(when (pgg-decode-packets)
|
|
(goto-char (point-min))
|
|
(pgg-parse-packets))))
|
|
|
|
(defun pgg-parse-armor (string)
|
|
(with-temp-buffer
|
|
(buffer-disable-undo)
|
|
(if (fboundp 'set-buffer-multibyte)
|
|
(set-buffer-multibyte nil))
|
|
(insert string)
|
|
(pgg-decode-armor-region (point-min)(point))))
|
|
|
|
(eval-and-compile
|
|
(defalias 'pgg-string-as-unibyte (if (fboundp 'string-as-unibyte)
|
|
'string-as-unibyte
|
|
'identity)))
|
|
|
|
(defun pgg-parse-armor-region (start end)
|
|
(pgg-parse-armor (pgg-string-as-unibyte (buffer-substring start end))))
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|
|
|
(provide 'pgg-parse)
|
|
|
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;;; arch-tag: 16c2eb82-1313-4a7c-a70f-420709b5b43e
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;;; pgg-parse.el ends here
|