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#|
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA.
**** tools for cryptography ****************************************************
Copyright Volker van Nek, 2015
1. string_to_octets(string [,encoding]) and octets_to_string(octets [,encoding]).
The default encoding depends on the underlying Lisp, the platform and the
application. The following example shows Maxima/GCL in a GNU/Linux terminal.
GCL uses no format definition and simply passes through the utf-8-octets encoded
by the terminal.
(%i1) octets: string_to_octets("abc");
(%o1) [61, 62, 63]
(%i2) octets_to_string(octets);
(%o2) abc
(%i3) ibase : obase : 16.$
(%i4) string: unicode(3bb);
(%o4) λ
(%i5) octets: string_to_octets(string);
(%o5) [0CE, 0BB]
(%i6) octets_to_string(octets);
(%o6) λ
(%i7) utf8_to_unicode(octets);
(%o7) 3BB
Maxima/SBCL in a GNU/Linux terminal using the optional encoding argument.
(%i1) ibase : obase : 16.$
(%i2) string: simplode(map(unicode, [3b1,3b2,3b3]));
(%o2) αβγ
(%i3) octets: string_to_octets(string, "ucs-2be");
(%o3) [3, 0B1, 3, 0B2, 3, 0B3]
(%i4) octets_to_string(octets, "ucs-2be");
(%o4) αβγ
(%i5) octets: string_to_octets(string, "iso-8859-7");
(%o5) [0E1, 0E2, 0E3]
(%i6) octets_to_string(octets, "iso-8859-7");
(%o6) αβγ
Examples of supported encodings:
CCL,CLISP,SBCL: utf-8, ucs-2be, iso-8859-1, cp1252, cp850
CMUCL: utf-8, utf-16-be, iso8859-1, cp1252
ECL: utf-8, ucs-2be, iso-8859-1, windows-cp1252, dos-cp850
2. number_to_octets(number) and octets_to_number(octets).
(%i1) ibase : obase : 16.$
(%i2) octets: [0ca,0fe,0ba,0be]$
(%i3) number: octets_to_number(octets);
(%o3) 0cafebabe
(%i4) number_to_octets(number);
(%o4) [0CA, 0FE, 0BA, 0BE]
3. octets_to_oid(octets) and oid_to_octets(string) compute object identifiers
(OIDs) from lists of octets and convert OIDs back to octets.
(%i1) ibase : obase : 16.$
(%i2) oid: octets_to_oid([2A,86,48,86,0F7,0D,1,1,1]);
(%o2) 1.2.840.113549.1.1.1
(%i3) oid_to_octets(oid);
(%o3) [2A, 86, 48, 86, 0F7, 0D, 1, 1, 1]
4. crc24sum(octets) returns the crc24 checksum of an octet-list. The returned
value is a string (default), a number or a list of octets.
Example: OpenPGP uses crc24
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.22 (GNU/Linux)
iQEcBAEBAgAGBQJVdCTzAAoJEG/1Mgf2DWAqCSYH/AhVFwhu1D89C3/QFcgVvZTM
wnOYzBUURJAL/cT+IngkLEpp3hEbREcugWp+Tm6aw3R4CdJ7G3FLxExBH/5KnDHi
rBQu+I7+3ySK2hpryQ6Wx5J9uZSa4YmfsNteR8up0zGkaulJeWkS4pjiRM+auWVe
vajlKZCIK52P080DG7Q2dpshh4fgTeNwqCuCiBhQ73t8g1IaLdhDN6EzJVjGIzam
/spqT/sTo6sw8yDOJjvU+Qvn6/mSMjC/YxjhRMaQt9EMrR1AZ4ukBF5uG1S7mXOH
WdiwkSPZ3gnIBhM9SuC076gLWZUNs6NqTeE3UzMjDAFhH3jYk1T7mysCvdtIkms=
=WmeC
-----END PGP SIGNATURE-----
(%i1) ibase : obase : 16.$
(%i2) sig64 : sconcat(
"iQEcBAEBAgAGBQJVdCTzAAoJEG/1Mgf2DWAqCSYH/AhVFwhu1D89C3/QFcgVvZTM",
"wnOYzBUURJAL/cT+IngkLEpp3hEbREcugWp+Tm6aw3R4CdJ7G3FLxExBH/5KnDHi",
"rBQu+I7+3ySK2hpryQ6Wx5J9uZSa4YmfsNteR8up0zGkaulJeWkS4pjiRM+auWVe",
"vajlKZCIK52P080DG7Q2dpshh4fgTeNwqCuCiBhQ73t8g1IaLdhDN6EzJVjGIzam",
"/spqT/sTo6sw8yDOJjvU+Qvn6/mSMjC/YxjhRMaQt9EMrR1AZ4ukBF5uG1S7mXOH",
"WdiwkSPZ3gnIBhM9SuC076gLWZUNs6NqTeE3UzMjDAFhH3jYk1T7mysCvdtIkms=" )$
(%i3) octets: base64_decode(sig64, 'list)$
(%i4) crc24: crc24sum(octets, 'list);
(%o4) [5A, 67, 82]
(%i5) base64(crc24);
(%o5) WmeC
|#
(in-package :maxima)
(eval-when
(:compile-toplevel :execute)
(defvar old-ibase-cryptools *read-base*)
(setq *read-base* 10.) )
;; -- string-octet-conversions: --------------------------------------------- ;;
(defun $string_to_octets (str &optional enc)
(unless (stringp str)
(gf-merror (intl:gettext "`string_to_octets': argument must be a string.")) )
(cons '(mlist simp) (string-to-octets str enc)) )
(defun string-to-octets (str &optional enc)
(setq enc (get-encoding enc "string_to_octets"))
(let ((ov #+ccl (ccl:encode-string-to-octets str :external-format enc) ;; maybe these (CCL, ECL) ..
#+clisp (ext:convert-string-to-bytes str enc)
#+ecl (ecl-string-to-octets str enc) ;; .. could move to intl.lisp
#- (or ccl clisp ecl) (intl::string-to-octets str enc) )) ;; GCL ignores enc
(coerce ov 'list) ))
;;
#+ecl
(defun ecl-string-to-octets (str enc)
(let ((a (make-array
(ceiling (* 1.2 (length str))) ;; initially add 20 % for non-ascii chars
:element-type '(unsigned-byte 8)
:adjustable t
:fill-pointer 0 )))
(with-open-stream
(stream (ext:make-sequence-output-stream a :external-format enc))
(format stream str)
a )))
(defun $octets_to_string (ol &optional enc)
(unless ($listp ol)
(gf-merror (intl:gettext
"`octets_to_string': argument must be a list of octets." )))
(octets-to-string (cdr ol) enc) )
(defun octets-to-string (ol &optional enc)
(setq enc (get-encoding enc "octets_to_string"))
(let ((ov (map-into
(make-array (length ol) :element-type '(unsigned-byte 8))
#'identity
ol )))
#+ccl (ccl:decode-string-from-octets ov :external-format enc)
#+clisp (ext:convert-string-from-bytes ov enc)
#+ecl (ecl-octets-to-string ov enc)
#- (or ccl clisp ecl) (intl::octets-to-string ov enc) ))
;;
#+ecl
(defun ecl-octets-to-string (ov enc)
(with-open-stream
(stream (ext:make-sequence-input-stream ov :external-format enc))
(read-line stream) ))
;; -- number-octet-conversions: --------------------------------------------- ;;
(defun word-to-octets (n) ;; assume that n fits into a word
(do ((k 4 (1- k)) octs)
((= k 0) octs)
(push (logand n #xff) octs)
(setq n (ash n -8.)) ))
(defun number-to-octets (n)
(do (octs) (())
(push (logand n #xff) octs)
(setq n (ash n -8.))
(when (= n 0) (return octs)) ))
(defun octets-to-number (octs)
(reduce #'(lambda (x y) (logior (ash x 8.) y)) octs) )
(defmfun $number_to_octets (n)
(unless (and (integerp n) (>= n 0))
(gf-merror (intl:gettext
"`number_to_octets': Argument must be a non-negative integer." )))
(cons '(mlist simp) (number-to-octets n)) )
(defmfun $octets_to_number (octs)
(unless ($listp octs)
(gf-merror (intl:gettext
"`octets_to_number': Argument must be a list of octets." )))
(octets-to-number (cdr octs)) )
;; -- object identifiers (OID): --------------------------------------------- ;;
;; examples:
;; 1.2.840.113549.1.1.1 - RSA encryption
;; 1.3.14.3.2.26 - SHA-1 hash algorithm
;; 2.16.840.1.101.3.4.2.1 - SHA-256 hash algorithm
;; 1.3.132.0.6 - secp112r1 - SEC 2 recommended elliptic curve
(defun oid-number-to-7bit (n)
(let (lst res)
(do () (())
(setq lst (cons (logand n 127.) lst)
n (ash n -7) )
(when (= n 0) (return)) )
(setq lst (nreverse lst)
res (list (car lst)) )
(dolist (bit7 (cdr lst) res)
(setq res (cons (logior bit7 128.) res)) )))
;;
(defun oid-to-octets (str)
(let* ((*read-base* 10.)
(lst (mapcar #'(lambda (s) (with-input-from-string (a s) (read a)))
(split str ".") )) ;; stringproc.lisp/split
oct octs )
(when (< (length lst) 2)
(gf-merror (intl:gettext "No valid OID: ~m") str) )
(setq oct (+ (* 40. (car lst)) (cadr lst))
octs (list oct) )
(dolist (n (cddr lst) octs)
(setq octs (append octs (oid-number-to-7bit n))) )))
;;
(defmfun $oid_to_octets (str)
(cons '(mlist simp) (oid-to-octets str)) )
(defun oid-split (lst)
(do (res n) (())
(setq n (car lst)
res (cons n res)
lst (cdr lst) )
(when (or (null lst) (not (logbitp 7 n)))
(return (values (nreverse res) lst)) )))
;;
(defun octets-to-oid-1 (lst)
(let ((res 0))
(dolist (n lst)
(setq res (logior (logand n 127.) res))
(unless (logbitp 7 n) (return res))
(setq res (ash res 7)) )))
;;
(defun octets-to-oid (lst)
(if (= (length lst) 0)
""
(let (str (tmp (car lst)) (*print-base* 10.))
(setq lst (cdr lst))
(multiple-value-bind (q r) (truncate tmp 40.)
(setq str ($sconcat q "." r))
(do () ((null lst) str)
(multiple-value-setq (tmp lst) (oid-split lst))
(setq str ($sconcat str "." (octets-to-oid-1 tmp))) )))))
;;
(defmfun $octets_to_oid (octets)
(octets-to-oid (cdr octets)) )
;; -- CRC24 checksum: ------------------------------------------------------- ;;
(defun crc24sum (lst)
(let ((r #xb704ce)
(poly #x1864cfb) )
(dolist (oct lst r)
(setq r (logxor r (ash oct 16.)))
(dotimes (i 8)
(setq r (ash r 1))
(when (logbitp 24. r) (setq r (logxor r poly))) ))))
;;
(defmfun $crc24sum (octets &optional (rtype '$string))
(if ($listp octets)
(let ((crc24 (crc24sum (cdr octets))))
(cond
((equal rtype '$list)
(cons '(mlist simp) (number-to-octets crc24)) )
((equal rtype '$number)
crc24 )
((equal rtype '$string)
(nstring-downcase (format nil "~6,'0x" crc24)) )
(t
(gf-merror (intl:gettext
"`crc24sum': Optional argument must be 'list, 'number or 'string." )))))
(gf-merror (intl:gettext
"`crc24sum': Argument must be a list of octets." ))))
(eval-when
(:compile-toplevel :execute)
(setq *read-base* old-ibase-cryptools) )
|
