Add QVICKBASIC program

README.org

@@ -2,6 +2,8 @@
 
 Solutions to the [[http://www.boundvariable.org/task.shtml][2006 ICFP Programming Contest]].
 
+*Warning: spoilers below!*
+
 ** Universal Machine
 
 The Universal Machine is implemented in [[um.c]]. Compile it with =make=
@@ -11,3 +13,33 @@ and run it on a UM program:
   ./um sandmark.umz # benchmark
   ./um codex.umz
 #+end_src
+
+Get the next program:
+
+#+begin_src sh
+  echo '(\\b.bb)(\\v.vv)06FHPVboundvarHRAk\np' | ./um codex.umz > codex_output
+  tail -c +196 codex_output > umix.um
+#+end_src
+
+** QVICKBASIC
+
+The fixed program is in [[hack.bas]]. We find the passwords of =ohmega=
+and =howie=.
+
+** Passwords found
+
+| user   | password      |
+|--------+---------------|
+| ohmega | bidirectional |
+| howie  | xyzzy         |
+| ftd    | falderal90    |
+
+** Publications found
+
+#+begin_src
+INTRO.LOG=200@999999|35e6f52e9bc951917c73af391e35e1d
+INTRO.MUA=5@999999|b9666432feff66e528a17fb69ae8e9a
+INTRO.UMD=10@999999|7005f80d6cd9b7b837802f1e58b11b8
+INTRO.QBC=10@999999|e6ee9c98b80b4dd04814a29a37bcba8
+INTRO.OUT=5@999999|69ca684f8c787cfe06694cb26f74a95
+#+end_src

hack.bas

@@ -0,0 +1,115 @@
+V        REM  +------------------------------------------------+
+X        REM  | HACK.BAS      (c) 19100   fr33 v4r14bl3z       |
+XV       REM  |                                                |
+XX       REM  | Brute-forces passwords on UM vIX.0 systems.    |
+XXV      REM  | Compile with Qvickbasic VII.0 or later:        |
+XXX      REM  |    /bin/qbasic hack.bas                        |
+XXXV     REM  | Then run:                                      |
+XL       REM  |   ./hack.exe username                          |
+XLV      REM  |                                                |
+L        REM  | This program is for educational purposes only! |
+LV       REM  +------------------------------------------------+
+LX       REM
+LXV      IF ARGS() > I THEN GOTO LXXXV
+LXX      PRINT "usage: ./hack.exe username"
+LXXV     PRINT CHR(X)
+LXXX     END
+LXXXV    REM
+XC       REM  get username from command line
+XCV      DIM username AS STRING
+C        username = ARG(II)
+CV       REM  common words used in passwords
+CX       DIM pwdcount AS INTEGER
+CXV      pwdcount = LIII
+CXX      DIM words(pwdcount) AS STRING
+CXXV     words(I) = "airplane"
+CXXX     words(II) = "alphabet"
+CXXXV    words(III) = "aviator"
+CXL      words(IV) = "bidirectional"
+CXLV     words(V) = "changeme"
+CL       words(VI) = "creosote"
+CLV      words(VII) = "cyclone"
+CLX      words(VIII) = "december"
+CLXV     words(IX) = "dolphin"
+CLXX     words(X) = "elephant"
+CLXXV    words(XI) = "ersatz"
+CLXXX    words(XII) = "falderal"
+CLXXXV   words(XIII) = "functional"
+CXC      words(XIV) = "future"
+CXCV     words(XV) = "guitar"
+CC       words(XVI) = "gymnast"
+CCV      words(XVII) = "hello"
+CCX      words(XVIII) = "imbroglio"
+CCXV     words(XIX) = "january"
+CCXX     words(XX) = "joshua"
+CCXXV    words(XXI) = "kernel"
+CCXXX    words(XXII) = "kingfish"
+CCXXXV   words(XXIII) = "(\b.bb)(\v.vv)"
+CCXL     words(XXIV) = "millennium"
+CCXLV    words(XXV) = "monday"
+CCL      words(XXVI) = "nemesis"
+CCLV     words(XXVII) = "oatmeal"
+CCLX     words(XXVIII) = "october"
+CCLXV    words(XXIX) = "paladin"
+CCLXX    words(XXX) = "pass"
+CCLXXV   words(XXXI) = "password"
+CCLXXX   words(XXXII) = "penguin"
+CCLXXXV  words(XXXIII) = "polynomial"
+CCXC     words(XXXIV) = "popcorn"
+CCXCV    words(XXXV) = "qwerty"
+CCC      words(XXXVI) = "sailor"
+CCCV     words(XXXVII) = "swordfish"
+CCCX     words(XXXVIII) = "symmetry"
+CCCXV    words(XXXIX) = "system"
+CCCXX    words(XL) = "tattoo"
+CCCXXV   words(XLI) = "thursday"
+CCCXXX   words(XLII) = "tinman"
+CCCXXXV  words(XLIII) = "topography"
+CCCXL    words(XLIV) = "unicorn"
+CCCXLV   words(XLV) = "vader"
+CCCL     words(XLVI) = "vampire"
+CCCLV    words(XLVII) = "viper"
+CCCLX    words(XLVIII) = "warez"
+CCCLXV   words(XLIX) = "xanadu"
+CCCLXX   words(L) = "xyzzy"
+CCCLXXV  words(LI) = "zephyr"
+CCCLXXX  words(LII) = "zeppelin"
+CCCLXXXV words(LIII) = "zxcvbnm"
+CCCXC    REM try each password
+CCCXCV   PRINT "attempting hack with " + pwdcount + " passwords " + CHR(X)
+CD       DIM i AS INTEGER
+CDV      i = I
+CDX      IF CHECKPASS(username, words(i)) THEN GOTO CDXXX
+CDXV     i = i + I
+CDXX     IF i > pwdcount THEN GOTO CDXLV
+CDXXV    GOTO CDX
+CDXXX    PRINT "found match!! for user " + username + CHR(X)
+CDXXXV   PRINT "password: " + words(i) + CHR(X)
+CDXL     END
+CDXLV    PRINT "no simple matches for user " + username + CHR(X)
+CDL      REM
+CDLV     REM  the above code will probably crack passwords for many
+CDLX     REM  users so I always try it first. when it fails, I try the
+CDLXV    REM  more expensive method below.
+CDLXX    REM
+CDLXXV   REM  passwords often take the form
+CDLXXX   REM    dictwordDD
+CDLXXXV  REM  where DD is a two-digit decimal number. try these next:
+CDXC     i = I
+CDXCV    DIM j AS INTEGER
+CDXCVI	 DIM k AS INTEGER
+D        IF i > pwdcount THEN GOTO DL
+DV	 j = I
+DVI	 k = I
+DX	 IF CHECKPASS(username, words(i) + CHR(XLVII + j) + CHR(XLVII + k)) THEN GOTO DXXXV
+DXV	 k = k + I
+DXVI	 IF k < XI THEN GOTO DX
+DXVII	 j = j + I
+DXX	 IF j < XI THEN GOTO DVI
+DXXV	 i = i + I
+DXXX	 GOTO D
+DXXXV	 PRINT "found match!! for user " + username + CHR(X)
+DXL	 PRINT "password: " + words(i) + CHR(XLVII + j) + CHR(XLVII + k) + CHR(X)
+DXLV	 END
+DL	 PRINT "no matches for user " + username + CHR(X)
+DLV	 END