;------------------------------------------------------------------------------- * * * Crypt * * * * Written 1992,1993,1994 by Daniel Weber * * * * IMPORTANT NOTE * * -------------- * * This is a naive encryption algorithm and elementary cryptanalytic techniques * * may easily crack it. Stronger and more complex algorithms are recommended * * for higher data security (f.e.: PGP (Pretty Good Privacy), ...). * * * * * * Filename crypt.s * * Author Daniel Weber * * Version 1.02 * * Start 1992 * * * * Last Revision 11.10.93 * * * ;------------------------------------------------------------------------------- output 'ram:crypt' opt o+,q+,ow-,qw-,sw- verbose base progbase filenote 'Crypt, Written 1992,1993,1994 by Daniel Weber' ;------------------------------------------------------------------------------- incdir 'include:' incdir 'routines:' include 'basicmac.r' include 'support.mac' incequ 'LVO.s' ;------------------------------------------------------------------------------- version equr "1.02" gea_progname equr "Crypt" ;-- startup control -- cws_CLIONLY set 1 ;for CLI usage only cws_EASYLIB set 1 ;-- user definitions -- AbsExecBase equ 4 DOS.LIB equ 1 ;startup code should open dos.library * cryptoffset is a user specified value to make 'crypt' a bit more individual. cryptoffset equ 11 workspace equ 400 ;------------------------------------------------------------------------------- progbase: jmp AutoDetach(pc) dc.b 0,"$VER: ",gea_progname," ",version," (",__date2,")",0 even ;---------------------------- clistartup: lea progbase(pc),a5 lea dxstart(pc),a1 move.w #(dxend-dxstart)/2-1,d7 .clr: clr.w (a1)+ dbra d7,.clr move.l a0,ArgStr(a5) move.l d0,ArgLen(a5) lea Title(pc),a0 ;print title printtext_ bsr ReadParameters ;read parameter line bne.s .exit ;invalid move.l Sourcefile(pc),d0 ;load source file move.l d0,d3 moveq #0,d1 moveq #0,d2 CALL_ LoadFile move.l d0,Buffer(a5) beq.s .fileerror move.l d1,Sourcelen(a5) move.l d2,BufferSize(a5) bsr DoCrypt ;encrypt buffer move.l Destfile(pc),d0 ;save file move.l d0,d3 move.l Buffer(pc),d1 move.l Sourcelen(pc),d2 CALL_ WriteToFile bne.s .fileerror .quit: move.l Buffer(pc),d0 ;free buffer beq.s .exit move.l d0,a1 move.l BufferSize(pc),d0 move.l 4.w,a6 jsr _LVOFreeMem(a6) .exit: moveq #0,d0 bra ReplyWBMsg ; ; error handler ; .fileerror: ;couldn't open file '%s' move.l d3,rawlist(a5) lea FileError1(pc),a0 lea rawlist(pc),a1 lea workbuffer(pc),a3 bsr DoRawFmt move.l a3,a0 printtext_ bra .quit ;------------------------------------------------------------------------------- * * subroutines * ;------------------------------------------------------------------------------- ;---------------------------------------------------------- ; ; ReadParameters - small command line parser ; ; a5: progbase ; ; => CCR: Z ok, zN failed usage, printed ; ReadParameters: move.l ArgStr(pc),a0 move.l ArgLen(pc),d7 clr.b -1(a0,d7.l) bsr .spacekiller cmp.b #"?",(a0) ;force usage? bne.s .pw tst.b 1(a0) beq.s .usage cmp.b #" ",1(a0) beq.s .usage .pw: cmp.b #"-",(a0) ;password seq cryptflag(a5) bne.s 1$ addq.l #1,a0 1$: move.l a0,PassWdStart(a5) move.l a0,d1 bsr.s .skip move.l a0,d0 sub.l d1,d0 move.l d0,PassWdLength(a5) beq.s .usage clr.b (a0)+ .src: bsr.s .spacekiller ;source file tst.b (a0) beq.s .usage move.l a0,Sourcefile(a5) bsr.s .skip add.l d4,Sourcefile(a5) sub.l d4,a0 clr.b (a0)+ .out: bsr.s .spacekiller ;output file tst.b (a0) beq.s .usage move.l a0,Destfile(a5) bsr.s .skip add.l d4,Destfile(a5) sub.l d4,a0 clr.b (a0)+ bsr.s .spacekiller tst.b (a0) bne.s .usage rts ; ; print usage ; .usage: lea Usage(pc),a0 printtext_ moveq #-1,d0 rts ; ; skip text ; ; => d4: correction ; .skip: moveq #0,d4 moveq #0,d5 cmp.b #$22,(a0) bne.s \do \strt: move.b (a0)+,d5 moveq #1,d4 \do: move.b (a0)+,d0 beq.s \ends cmp.b d0,d5 bne.s .d2 cmp.b (a0)+,d5 bne.s \ends .d2: cmp.b #" ",d0 bne.s \do tst.b d5 bne.s \do \ends: subq.l #1,a0 rts ; ; skip spaces ; .spacekiller: cmp.b #" ",(a0)+ beq.s .spacekiller subq.l #1,a0 rts ;---------------------------------------------------------- ; ; DoRawFmt ; ; a0: format ; a1: data stream ; a3: dest. buffer ; DoRawFmt: movem.l d0-a6,-(a7) lea .setin(pc),a2 move.l 4.w,a6 jsr _LVORawDoFmt(a6) movem.l (a7)+,d0-a6 rts .setin: move.b d0,(a3)+ rts ;---------------------------------------------------------- ; ; DoCrypt - encrypt buffer ; ; simple encryption algorithm ; ; crypt: pass1-pass2-pass3 ; decrypt: pass3-pass4-pass5 ; DoCrypt: move.l Sourcefile(pc),rawlist(a5) ;print action text move.l Destfile(pc),rawlist+4(a5) lea CryptTxt(pc),a0 tst.b cryptflag(a5) beq.s .crypt lea DeCryptTxt(pc),a0 .crypt: lea rawlist(pc),a1 lea workbuffer(pc),a3 bsr DoRawFmt move.l a3,a0 printtext_ ;------------------ tst.b cryptflag(a5) bne.s .pass3 .pass1: move.l Buffer(pc),a0 ;pass1 for encryption only move.l Sourcelen(pc),d7 beq .out lsr.l #1,d7 bne.s .in1 bra.s .pass2 .loop1: move.w (a0)+,d0 eor.w d0,(a0) .in1: subq.l #1,d7 bne.s .loop1 .pass2: move.l Sourcelen(pc),d7 ;pass2 for encryption only move.l Buffer(pc),a0 lea (a0,d7.l),a1 moveq #cryptoffset,d3 ;user specified value lea (a0,d3.l),a2 bra.s .chk2 .loop2: eor.b d7,(a2) add.l d3,a2 .chk2: move.l a2,d2 sub.l a1,d2 bmi.s .in2 lea (a0,d2.l),a2 bra.s .chk2 .in2: subq.l #1,d7 bne.s .loop2 .pass3: move.l PassWdStart(pc),a1 ;pass3 for de/encryption move.l a1,a2 moveq #cryptoffset/3,d4 ;user specified value .prep: move.b (a2)+,d0 beq.s 0$ add.b d0,d4 bra.s .prep 0$: move.l Buffer(pc),a0 moveq #cryptoffset*2,d2 ;user specified start value move.l Sourcelen(pc),d7 .loop3: move.b (a1)+,d0 bne.s 1$ move.l PassWdStart(pc),a1 move.b (a1)+,d0 subq.b #cryptoffset/2,d2 1$: add.b d2,d0 add.b #cryptoffset,d2 add.b d4,d0 eor.b d0,(a0)+ and.b #cryptoffset,d0 ;user specified value beq.s 2$ move.b (a1),d0 eor.b d0,d2 2$: subq.l #1,d7 bne.s .loop3 tst.b cryptflag(a5) beq.s .out .pass4: move.l Sourcelen(pc),d7 ;pass4 for decryption only move.l Buffer(pc),a0 lea (a0,d7.l),a1 moveq #cryptoffset,d3 ;user specified value lea (a0,d3.l),a2 bra.s .chk4 .loop4: eor.b d7,(a2) add.l d3,a2 .chk4: move.l a2,d2 sub.l a1,d2 bmi.s .in4 lea (a0,d2.l),a2 bra.s .chk4 .in4: subq.l #1,d7 bne.s .loop4 .pass5: move.l Buffer(pc),a0 ;pass5 for decryption only move.l Sourcelen(pc),d7 beq.s .out lsr.l #1,d7 beq.s .out add.l d7,a0 add.l d7,a0 bra.s .in5 .loop5: move.w -4(a0),d0 eor.w d0,-(a0) .in5: subq.l #1,d7 bne.s .loop5 .out: rts ;------------------------------------------------------------------------------- * * external routines * ;------------------------------------------------------------------------------- include startup4.r include dosfile.r ;------------------------------------------------------------------------------- * * data area * ;------------------------------------------------------------------------------- Title: dc.b $9b,"1mCrypt",$9b,"0m - small encryption program v" dc.b version,$a dc.b "Written 1992 by Daniel Weber",$a,$a,0 Usage: dc.b "Usage: ",$9b,"3mCrypt " dc.b "",$9b,"0m",$a,0 FileError1: dc.b "Couldn't open file '%s'.",$a,0 DeCryptTxt: dc.b "de" CryptTxt: dc.b "crypting file '%s' to '%s'.",$a,0 even dxstart ;------------------------------------------------------------------------------- ArgStr: dx.l 1 ;parameter line ArgLen: dx.l 1 ;parameter line length cryptflag: dx.b 1 ;0: crypt -: decrypt aligndx.w PassWdStart: dx.l 1 ;pointer to password PassWdLength: dx.l 1 ;length of password Buffer: dx.l 1 ;buffer address BufferSize: dx.l 1 ;buffer size Sourcefile: dx.l 1 ;pointer to source file Sourcelen: dx.l 1 ;length of source file Destfile: dx.l 1 ;pointer to destination file rawlist: dx.l 2 ;rawlist for RawDoFmt workbuffer: dx.b workspace ;some workspace ;------------------------------------------------------------------------------- aligndx.w dxend: end