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    1: <script type="text/javascript" language="JavaScript">
    2: // The LearningOnline Network with CAPA
    3: // Encryption Routines according to Data Encryption Standard DES
    4: // Federal Information Processing Standards Publication 46-2 (1993 Dec 30)
    5: //
    6: // $Id: londes.js,v 1.8 2004/08/03 15:03:35 matthew Exp $
    7: //
    8: // Copyright Michigan State University Board of Trustees
    9: //
   10: // This file is part of the LearningOnline Network with CAPA (LON-CAPA).
   11: //
   12: // LON-CAPA is free software; you can redistribute it and/or modify
   13: // it under the terms of the GNU General Public License as published by
   14: // the Free Software Foundation; either version 2 of the License, or
   15: // (at your option) any later version.
   16: //
   17: // LON-CAPA is distributed in the hope that it will be useful,
   18: // but WITHOUT ANY WARRANTY; without even the implied warranty of
   19: // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   20: // GNU General Public License for more details.
   21: //
   22: // You should have received a copy of the GNU General Public License
   23: // along with LON-CAPA; if not, write to the Free Software
   24: // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   25: //
   26: // /home/httpd/html/adm/gpl.txt
   27: //
   28: // http://www.lon-capa.org/
   29: //
   30: // JavaScript Implementation by Gerd Kortemeyer
   31: // 1997,06/27/00,06/28 Gerd Kortemeyer
   32: 
   33: // Global variables
   34: 
   35: // Array of integers with i-th bit set
   36: var bit=new Array(31);
   37: // Initial permutation IP for right part
   38: var riparr=new Array(31);
   39: // Inverse permutation IP-1
   40: var liiparr=new Array(31);
   41: var uiiparr=new Array(31);
   42: // Key vectors
   43: var uk=new Array(16);
   44: var lk=new Array(16);
   45: // Upper- and lower 32-bit of external key
   46: var uextkey=0;
   47: var lextkey=0;
   48: // Upper- and lower 32-bit of block
   49: var ublock=0;
   50: var lblock=0;
   51: // Upper and lower 24 bit of expanded right vector
   52: var lexpand=0;
   53: var uexpand=0;
   54: // S-box array
   55: var sbarr=new Array(511);
   56: // E expansion
   57: var etarr=new Array(47);
   58: // P permutation
   59: var pparr=new Array(31);
   60: // r- and l-vector
   61: var rv=0;
   62: var lv=0;
   63: // Blocks of data for text
   64: var b0=0;
   65: var b1=0;
   66: var b2=0;
   67: var b3=0;
   68: // Text variable
   69: var text="";
   70: 
   71: // Initialize table arrays and perform self test
   72: 
   73: function init() {
   74:      window.status="Initializing ...";
   75:     var rip="58504234261810 260524436282012 462544638302214 664564840322416 8";
   76:     var iip=" 8162432 7152331 6142230 5132129 4122028 3111927 2101826 1 91725";
   77:      var sb
   78:      sb ="14 413 1 21511 8 310 612 5 9 0 7";
   79:      sb+=" 015 7 414 213 110 61211 9 5 3 8";
   80:      sb+=" 4 114 813 6 2111512 9 7 310 5 0";
   81:      sb+="1512 8 2 4 9 1 7 511 31410 0 613";
   82:      sb+="15 1 814 611 3 4 9 7 21312 0 510";
   83:      sb+=" 313 4 715 2 81412 0 110 6 911 5";
   84:      sb+=" 014 71110 413 1 5 812 6 9 3 215";
   85:      sb+="13 810 1 315 4 211 6 712 0 514 9";
   86:      sb+="10 0 914 6 315 5 11312 711 4 2 8";
   87:      sb+="13 7 0 9 3 4 610 2 8 514121115 1";
   88:      sb+="13 6 4 9 815 3 011 1 212 51014 7";
   89:      sb+=" 11013 0 6 9 8 7 41514 311 5 212";
   90:      sb+=" 71314 3 0 6 910 1 2 8 51112 415";
   91:      sb+="13 811 5 615 0 3 4 7 212 11014 9";
   92:      sb+="10 6 9 01211 71315 1 314 5 2 8 4";
   93:      sb+=" 315 0 610 113 8 9 4 51112 7 214";
   94:      sb+=" 212 4 1 71011 6 8 5 31513 014 9";
   95:      sb+="1411 212 4 713 1 5 01510 3 9 8 6";
   96:      sb+=" 4 2 1111013 7 815 912 5 6 3 014";
   97:      sb+="11 812 7 114 213 615 0 910 4 5 3";
   98:      sb+="12 11015 9 2 6 8 013 3 414 7 511";
   99:      sb+="1015 4 2 712 9 5 6 11314 011 3 8";
  100:      sb+=" 91415 5 2 812 3 7 0 410 11311 6";
  101:      sb+=" 4 3 212 9 515101114 1 7 6 0 813";
  102:      sb+=" 411 21415 0 813 312 9 7 510 6 1";
  103:      sb+="13 011 7 4 9 11014 3 512 215 8 6";
  104:      sb+=" 1 4111312 3 7141015 6 8 0 5 9 2";
  105:      sb+=" 61113 8 1 410 7 9 5 01514 2 312";
  106:      sb+="13 2 8 4 61511 110 9 314 5 012 7";
  107:      sb+=" 11513 810 3 7 412 5 611 014 9 2";
  108:      sb+=" 711 4 1 91214 2 0 6101315 3 5 8";
  109:      sb+=" 2 114 7 410 8131512 9 0 3 5 611";
  110:      var et
  111:      et ="32 1 2 3 4 5 4 5 6 7 8 9 8 910111213121314151617";
  112:      et+="1617181920212021222324252425262728292829303132 1";
  113:      var pp="16 7202129122817 1152326 5183110 2 824143227 3 9191330 62211 425";
  114:      bit[0]=1;
  115:      for (var i=1; i<=31;i++) { bit[i]=bit[i-1]<<1; }
  116:      for (i=0; i<=31;i++) {
  117:         riparr[i]=parseInt(rip.substring(i*2,i*2+2));
  118:         pparr[i]=parseInt(pp.substring(i*2,i*2+2));
  119:      }
  120:      for (i=0;i<=15;i++) {
  121:         liiparr[i]=parseInt(iip.substring(i*2,i*2+2));
  122:         uiiparr[i]=parseInt(iip.substring(32+i*2,32+i*2+2));
  123:      }
  124:      for (i=0;i<=511;i++) {
  125:         sbarr[i]=parseInt(sb.substring(i*2,i*2+2));
  126:      }
  127:      for (i=0;i<=47;i++) {
  128:         etarr[i]=parseInt(et.substring(i*2,i*2+2));
  129:      }
  130: 
  131:      window.status="Ready.";
  132: }
  133: 
  134: // Return a string with hex-representation of integer
  135: 
  136: function hexstring(i) {
  137:      var hstr="";
  138:      var hchr="0123456789abcdef";
  139:      for (var k=28; k>=0; k=k-4) {
  140:          j=0;
  141:          for (var m=0; m<=3; m++) { if ((i&bit[k+m])!=0) { j=j|bit[m]; } }
  142:          hstr+=hchr.substring(j,j+1);
  143:      }   
  144:      return(hstr);
  145: }
  146: 
  147: // Shift a 28-bit register one time
  148: 
  149: function shift(sreg) {
  150:      var bit27=(sreg&bit[0])<<27;
  151:      return (sreg>>1)|bit27;
  152: }
  153:         
  154: // Initialize key-arrays according to uextkey and lextkey
  155: 
  156: function initkeys() {
  157:      init();
  158: // Constants  
  159:      var celements="574941332517 9 158504234261810 259514335271911 360524436";
  160:      var delements="63554739312315 762544638302214 661534537292113 5282012 4";
  161:      var lkelements="14171124 1 5 32815 62110231912 426 816 7272013 2";
  162:      var ukelements="415231374755304051453348444939563453464250362932";
  163:      var shifttimes="1122222212222221";
  164: // PC-2 order
  165:      var ukarr=new Array(23);
  166:      var lkarr=new Array(23);
  167:      for (i=0;i<=23;i++) {
  168:         ukarr[i]=parseInt(ukelements.substring(i*2,i*2+2));
  169:         lkarr[i]=parseInt(lkelements.substring(i*2,i*2+2));
  170:      }
  171: // Initialize c and d
  172:      var bt;
  173:      var c=0;
  174:      var d=0;
  175:      for (var i=0; i<=27;i++) {
  176:           bt=parseInt(celements.substring(i*2,i*2+2));
  177:           if (bt<=32) {
  178:               if ((uextkey & bit[31-(bt-1)]) != 0) { c=c|bit[i]; }
  179:           } else {
  180:               if ((lextkey & bit[31-(bt-33)]) != 0) { c=c|bit[i]; }
  181:           }
  182:           bt=parseInt(delements.substring(i*2,i*2+2));
  183:           if (bt<=32) {
  184:               if ((uextkey & bit[31-(bt-1)]) != 0) { d=d|bit[i]; }
  185:           } else {
  186:               if ((lextkey & bit[31-(bt-33)]) != 0) { d=d|bit[i]; }
  187:           }
  188:       }
  189: // Initialize the k vectors
  190:       for (i=1;i<=16;i++) {
  191: // Shift c and d
  192:           if (shifttimes.substring(i-1,i)=='1') {
  193:               c=shift(c);
  194:               d=shift(d);
  195:           } else {
  196:               c=shift(shift(c));
  197:               d=shift(shift(d));
  198:           }
  199:           uk[i]=0;
  200:           lk[i]=0;
  201:           for (j=0; j<=23;j++) {            
  202:             if ((d&bit[ukarr[j]-29])!=0) { lk[i]=lk[i]|bit[23-j]; }
  203:             if ((c&bit[lkarr[j]-1])!=0) { uk[i]=uk[i]|bit[23-j]; }
  204:           }
  205:       }
  206: }
  207: 
  208: // Initial permutation of ublock and lblock into rv and lv
  209: 
  210: function ip() {
  211:      var bt;
  212:      rv=0;
  213:      lv=0;
  214:      for (var i=0; i<=31;i++) {
  215:           bt=riparr[i];
  216:           if (bt<=32) {
  217:               if ((lblock & bit[bt-1]) != 0) { rv=rv|bit[i]; }
  218:           } else {
  219:               if ((ublock & bit[bt-33]) != 0) { rv=rv|bit[i]; }
  220:           }
  221:           if (bt<=33) {
  222:               if ((lblock & bit[bt-2]) != 0) { lv=lv|bit[i]; }
  223:           } else {
  224:               if ((ublock & bit[bt-34]) != 0) { lv=lv|bit[i]; }
  225:           }     
  226:      }
  227: }
  228: 
  229: // Inverse Initial Permutation IP-1, input rv,lv, output lblock,ublock
  230: 
  231: function invip() {
  232:      var bt;
  233:      ublock=0;
  234:      lblock=0;
  235:      for (var i=0; i<=15;i++) {
  236:           bt=liiparr[i];
  237:           if ((rv & bit[bt-1]) != 0) { lblock=lblock|bit[i*2]; }
  238:           if ((lv & bit[bt-1]) != 0) { lblock=lblock|bit[i*2+1]; }
  239:           bt=uiiparr[i];
  240:           if ((rv & bit[bt-1]) != 0) { ublock=ublock|bit[i*2]; }
  241:           if ((lv & bit[bt-1]) != 0) { ublock=ublock|bit[i*2+1]; }
  242:      }
  243: }
  244: 
  245: // Expansion of right vector according to E, input rv
  246: 
  247: function expand() {
  248:     var bt;
  249:     uexpand=0;
  250:     lexpand=0;
  251:     for (var i=0; i<=23; i++) {
  252:        bt=etarr[i];
  253:        if (rv & bit[bt-1]) { lexpand=lexpand|bit[i]; } 
  254:     }
  255:     for (i=24; i<=47; i++) {
  256:        bt=etarr[i];
  257:        if (rv & bit[bt-1]) { uexpand=uexpand|bit[i-24]; }
  258:     }
  259: }
  260: 
  261: // Permutes rv according to P, input/output rv
  262: 
  263: function permute() {
  264:     var prv=rv;
  265:     rv=0;
  266:     for (var i=0; i<=31; i++) {
  267:        if ((prv&bit[31-(pparr[i]-1)])!=0) { rv=rv|bit[31-i]; }
  268:     }
  269: }
  270: 
  271: // Performs stage si of the encryption, input/output rv
  272: 
  273: function stage(si) {
  274:     expand();
  275:     var uadd=uexpand^uk[si];
  276:     var ladd=lexpand^lk[si];
  277:     rv=0;
  278:     var ks=0;
  279:     for (var ki=42;ki>=24;ki=ki-6) {
  280:        rv=rv<<4;
  281:        var i=0;
  282:        if ((uadd&bit[ki-24])!=0) { i=i|bit[0]; }
  283:        if ((uadd&bit[ki-19])!=0) { i=i|bit[1]; }
  284:        var j=0;
  285:        for (var kj=0; kj<=3; kj++) {
  286:           if ((uadd&bit[ki-23+kj])!=0) { j=j|bit[kj]; }
  287:        }
  288:        rv=rv|sbarr[ks*64+i*16+j];
  289:        ks++;
  290:     } 
  291:     for (var ki=18;ki>=0;ki=ki-6) {
  292:        rv=rv<<4;
  293:        var i=0;
  294:        if ((ladd&bit[ki]  )!=0) { i=i|bit[0]; }
  295:        if ((ladd&bit[ki+5])!=0) { i=i|bit[1]; }
  296:        var j=0;
  297:        for (var kj=0; kj<=3; kj++) {
  298:           if ((ladd&bit[ki+1+kj])!=0) { j=j|bit[kj]; }
  299:        }
  300:        rv=rv|sbarr[ks*64+i*16+j];
  301:        ks++;
  302:     }
  303:     permute();
  304: }
  305: 
  306: // Encryption
  307: 
  308: function encrypt() {
  309:     ip();
  310:     for (var i=1; i<=16; i++) {
  311:         var prv=rv;
  312:         stage(i);
  313:         rv=rv^lv;
  314:         lv=prv;
  315:     }
  316:     invip();
  317: }
  318: 
  319: // Decryption
  320: 
  321: function decrypt() {
  322:     ip();
  323:     for (var i=16; i>=1; i--) {
  324:         var prv=rv;
  325:         stage(i);
  326:         rv=rv^lv;
  327:         lv=prv;
  328:     }
  329:     invip();
  330: }
  331: 
  332: // Put text into b0,b1,b2,b3
  333:     
  334: function block(text) {;
  335: var equiv= "*+ -./0123456789......@";
  336:     equiv+="ABCDEFGHIJKLMNOPQRSTUVWXYZ    _ ";
  337:     equiv+="abcdefghijklmnopqrstuvwxyz";
  338:     var tl=text.length;
  339:     if (tl>=16) { tl=15; }
  340:     text+="                ";
  341:     text=escape(text);
  342:     var i;
  343:     var c;
  344:     var conv='';
  345:     var j=0;
  346:     for (i=0;i<15;i++) {
  347:         if (text.charAt(j)=='%') {
  348:            conv+=text.charAt(j+1)+text.charAt(j+2);
  349:            j=j+3;
  350:         } else {
  351:            c=hexstring(42+equiv.indexOf(text.charAt(j)));
  352:            conv+=c.substr(6,2);
  353:            j++;
  354:         }
  355:     }
  356:     b3=tl*bit[24]+parseInt("0x"+conv.substr(0,6));
  357:     b2=parseInt("0x"+conv.substr(6,8));
  358:     b1=parseInt("0x"+conv.substr(14,8));
  359:     b0=parseInt("0x"+conv.substr(22,8));
  360: 
  361: }
  362: 
  363: function crypted(text) {
  364:     block(text);
  365:     lblock=b0;
  366:     ublock=b1;
  367:     encrypt();
  368:     b0=lblock;
  369:     b1=ublock;
  370:     lblock=b2;
  371:     ublock=b3;
  372:     encrypt();
  373:     b2=lblock;
  374:     b3=ublock;
  375:     return(hexstring(b3)+hexstring(b2)+hexstring(b1)+hexstring(b0));
  376: }
  377: 
  378: </script>