railfence-experiment-2.ipynb

   1 {
   2  "metadata": {
   3   "name": "",
   4   "signature": "sha256:285f7a82eaf5cc815e9a686ebce8aa2cfbdecb14f2473c9b5dfe0aedafcd727c"
   5  },
   6  "nbformat": 3,
   7  "nbformat_minor": 0,
   8  "worksheets": [
   9   {
  10    "cells": [
  11     {
  12      "cell_type": "code",
  13      "collapsed": false,
  14      "input": [
  15       "from cipher import *\n",
  16       "from cipherbreak import *\n",
  17       "import math"
  18      ],
  19      "language": "python",
  20      "metadata": {},
  21      "outputs": [],
  22      "prompt_number": 79
  23     },
  24     {
  25      "cell_type": "code",
  26      "collapsed": false,
  27      "input": [
  28       "def railfence_encipher(message, height, fillvalue=' '):\n",
  29       "    \"\"\"Railfence cipher\n",
  30       "\n",
  31       "    >>> railfence_encipher('hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers', 2, fillvalue='!')\n",
  32       "    'hlohraateerishsslnpeefetotsigaleccpeselteevsmhatetiiaogicotxfretnrifneihr!'\n",
  33       "    >>> railfence_encipher('hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers', 3, fillvalue='!')\n",
  34       "    'horaersslpeeosglcpselteevsmhatetiiaogicotxfretnrifneihr!!lhateihsnefttiaece!'\n",
  35       "    >>> railfence_encipher('hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers', 5, fillvalue='!')\n",
  36       "    'hresleogcseeemhetaocofrnrner!!lhateihsnefttiaece!!ltvsatiigitxetifih!!oarspeslp!'\n",
  37       "    >>> railfence_encipher('hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers', 10, fillvalue='!')\n",
  38       "    'hepisehagitnr!!lernesge!!lmtocerh!!otiletap!!tseaorii!!hassfolc!!evtitffe!!rahsetec!!eixn!'\n",
  39       "    \"\"\"\n",
  40       "    sections = chunks(message, (height - 1) * 2, fillvalue=fillvalue)\n",
  41       "    # Add the top row\n",
  42       "    rows = [s[0] for s in sections]\n",
  43       "    # process the middle rows of the grid\n",
  44       "    for r in range(1, height - 1):\n",
  45       "        rows += [s[r] + s[-r] for s in sections]\n",
  46       "    # process the bottom row\n",
  47       "    rows += [s[height - 1] for s in sections]\n",
  48       "    return ''.join(rows)"
  49      ],
  50      "language": "python",
  51      "metadata": {},
  52      "outputs": [],
  53      "prompt_number": 2
  54     },
  55     {
  56      "cell_type": "code",
  57      "collapsed": false,
  58      "input": [
  59       "pt = 'hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers'\n",
  60       "height = 6"
  61      ],
  62      "language": "python",
  63      "metadata": {},
  64      "outputs": [],
  65      "prompt_number": 195
  66     },
  67     {
  68      "cell_type": "code",
  69      "collapsed": false,
  70      "input": [
  71       "sections = chunks(pt, (height - 1) * 2, fillvalue='!')\n",
  72       "n_sections = len(sections)\n",
  73       "# Add the top row\n",
  74       "rows = [' '.join([s[0] for s in sections])]\n",
  75       "# process the middle rows of the grid\n",
  76       "for r in range(1, height - 1):\n",
  77       "    # rows += [''.join([s[r:r+1] + s[n_sections-r:n_sections-r+1] for s in sections])]\n",
  78       "    rows += [''.join([s[r] + s[-r] for s in sections])]\n",
  79       "# process the bottom row\n",
  80       "# rows += [' '.join([s[height - 1:height] for s in sections])]\n",
  81       "rows += [' '.join([s[height - 1] for s in sections])]\n",
  82       "rows"
  83      ],
  84      "language": "python",
  85      "metadata": {},
  86      "outputs": [
  87       {
  88        "metadata": {},
  89        "output_type": "pyout",
  90        "prompt_number": 196,
  91        "text": [
  92         "['h a r s e t l e',\n",
  93         " 'eevatiacoreifhr!',\n",
  94         " 'lraeislefosaeps!',\n",
  95         " 'lesheioitftrni!!',\n",
  96         " 'ohteshnpetigcc!!',\n",
  97         " 't m t g x n e !']"
  98        ]
  99       }
 100      ],
 101      "prompt_number": 196
 102     },
 103     {
 104      "cell_type": "code",
 105      "collapsed": false,
 106      "input": [
 107       "sections"
 108      ],
 109      "language": "python",
 110      "metadata": {},
 111      "outputs": [
 112       {
 113        "metadata": {},
 114        "output_type": "pyout",
 115        "prompt_number": 197,
 116        "text": [
 117         "['hellothere',\n",
 118         " 'avastmehea',\n",
 119         " 'rtiesthisi',\n",
 120         " 'salongpiec',\n",
 121         " 'eoftextfor',\n",
 122         " 'testingrai',\n",
 123         " 'lfenceciph',\n",
 124         " 'ers!!!!!!!']"
 125        ]
 126       }
 127      ],
 128      "prompt_number": 197
 129     },
 130     {
 131      "cell_type": "code",
 132      "collapsed": false,
 133      "input": [
 134       "sections = chunks(pt, (height - 1) * 2, fillvalue='')\n",
 135       "# Add the top row\n",
 136       "rows = [' '.join([s[0] for s in sections])]\n",
 137       "# process the middle rows of the grid\n",
 138       "for r in range(1, height-1):\n",
 139       "    print(r, height*2-r-2, ':', sections[0][r:r+1], sections[0][height*2-r-2:height*2-r-1])\n",
 140       "    rows += [''.join([s[r:r+1] + s[height*2-r-2:height*2-r-1] for s in sections])]\n",
 141       "    # rows += [''.join([s[r] + s[-r] for s in sections])]\n",
 142       "# process the bottom row\n",
 143       "rows += [' '.join([s[height - 1:height] for s in sections])]\n",
 144       "# rows += [' '.join([s[height - 1] for s in sections])]\n",
 145       "rows"
 146      ],
 147      "language": "python",
 148      "metadata": {},
 149      "outputs": [
 150       {
 151        "output_type": "stream",
 152        "stream": "stdout",
 153        "text": [
 154         "1 9 : e e\n",
 155         "2 8 : l r\n",
 156         "3 7 : l e\n",
 157         "4 6 : o h\n"
 158        ]
 159       },
 160       {
 161        "metadata": {},
 162        "output_type": "pyout",
 163        "prompt_number": 198,
 164        "text": [
 165         "['h a r s e t l e',\n",
 166         " 'eevatiacoreifhr',\n",
 167         " 'lraeislefosaeps',\n",
 168         " 'lesheioitftrni',\n",
 169         " 'ohteshnpetigcc',\n",
 170         " 't m t g x n e ']"
 171        ]
 172       }
 173      ],
 174      "prompt_number": 198
 175     },
 176     {
 177      "cell_type": "code",
 178      "collapsed": false,
 179      "input": [
 180       "sections"
 181      ],
 182      "language": "python",
 183      "metadata": {},
 184      "outputs": [
 185       {
 186        "metadata": {},
 187        "output_type": "pyout",
 188        "prompt_number": 199,
 189        "text": [
 190         "['hellothere',\n",
 191         " 'avastmehea',\n",
 192         " 'rtiesthisi',\n",
 193         " 'salongpiec',\n",
 194         " 'eoftextfor',\n",
 195         " 'testingrai',\n",
 196         " 'lfenceciph',\n",
 197         " 'ers']"
 198        ]
 199       }
 200      ],
 201      "prompt_number": 199
 202     },
 203     {
 204      "cell_type": "code",
 205      "collapsed": false,
 206      "input": [
 207       "ct = ''.join(c for c in ''.join(rows) if c != ' ')\n",
 208       "ct"
 209      ],
 210      "language": "python",
 211      "metadata": {},
 212      "outputs": [
 213       {
 214        "metadata": {},
 215        "output_type": "pyout",
 216        "prompt_number": 200,
 217        "text": [
 218         "'harsetleeevatiacoreifhrlraeislefosaepslesheioitftrniohteshnpetigcctmtgxne'"
 219        ]
 220       }
 221      ],
 222      "prompt_number": 200
 223     },
 224     {
 225      "cell_type": "code",
 226      "collapsed": false,
 227      "input": [
 228       "n_sections = math.ceil(len(pt) / ((height - 1) * 2))\n",
 229       "n_sections"
 230      ],
 231      "language": "python",
 232      "metadata": {},
 233      "outputs": [
 234       {
 235        "metadata": {},
 236        "output_type": "pyout",
 237        "prompt_number": 202,
 238        "text": [
 239         "8"
 240        ]
 241       }
 242      ],
 243      "prompt_number": 202
 244     },
 245     {
 246      "cell_type": "code",
 247      "collapsed": false,
 248      "input": [
 249       "padding_to_add = n_sections * (height - 1) * 2 - len(pt)\n",
 250       "padding_to_add"
 251      ],
 252      "language": "python",
 253      "metadata": {},
 254      "outputs": [
 255       {
 256        "metadata": {},
 257        "output_type": "pyout",
 258        "prompt_number": 203,
 259        "text": [
 260         "7"
 261        ]
 262       }
 263      ],
 264      "prompt_number": 203
 265     },
 266     {
 267      "cell_type": "code",
 268      "collapsed": false,
 269      "input": [
 270       "row_lengths = [n_sections] * (height - 1) * 2\n",
 271       "row_lengths"
 272      ],
 273      "language": "python",
 274      "metadata": {},
 275      "outputs": [
 276       {
 277        "metadata": {},
 278        "output_type": "pyout",
 279        "prompt_number": 204,
 280        "text": [
 281         "[8, 8, 8, 8, 8, 8, 8, 8, 8, 8]"
 282        ]
 283       }
 284      ],
 285      "prompt_number": 204
 286     },
 287     {
 288      "cell_type": "code",
 289      "collapsed": false,
 290      "input": [
 291       "for i in range((height - 1) * 2 - 1, (height - 1) * 2 - (padding_to_add + 1), -1):\n",
 292       "    row_lengths[i] -= 1\n",
 293       "row_lengths"
 294      ],
 295      "language": "python",
 296      "metadata": {},
 297      "outputs": [
 298       {
 299        "metadata": {},
 300        "output_type": "pyout",
 301        "prompt_number": 205,
 302        "text": [
 303         "[8, 8, 8, 7, 7, 7, 7, 7, 7, 7]"
 304        ]
 305       }
 306      ],
 307      "prompt_number": 205
 308     },
 309     {
 310      "cell_type": "code",
 311      "collapsed": false,
 312      "input": [
 313       "folded_row_lengths = [row_lengths[0]]\n",
 314       "for i in range(1, height-1):\n",
 315       "    folded_row_lengths += [row_lengths[i] + row_lengths[-i]]\n",
 316       "folded_row_lengths += [row_lengths[height - 1]]\n",
 317       "folded_row_lengths"
 318      ],
 319      "language": "python",
 320      "metadata": {},
 321      "outputs": [
 322       {
 323        "metadata": {},
 324        "output_type": "pyout",
 325        "prompt_number": 206,
 326        "text": [
 327         "[8, 15, 15, 14, 14, 7]"
 328        ]
 329       }
 330      ],
 331      "prompt_number": 206
 332     },
 333     {
 334      "cell_type": "code",
 335      "collapsed": false,
 336      "input": [
 337       "rows = []\n",
 338       "row_start = 0\n",
 339       "for i in folded_row_lengths:\n",
 340       "    rows += [ct[row_start:row_start + i]]\n",
 341       "    row_start += i\n",
 342       "rows"
 343      ],
 344      "language": "python",
 345      "metadata": {},
 346      "outputs": [
 347       {
 348        "metadata": {},
 349        "output_type": "pyout",
 350        "prompt_number": 207,
 351        "text": [
 352         "['harsetle',\n",
 353         " 'eevatiacoreifhr',\n",
 354         " 'lraeislefosaeps',\n",
 355         " 'lesheioitftrni',\n",
 356         " 'ohteshnpetigcc',\n",
 357         " 'tmtgxne']"
 358        ]
 359       }
 360      ],
 361      "prompt_number": 207
 362     },
 363     {
 364      "cell_type": "code",
 365      "collapsed": false,
 366      "input": [
 367       "down_rows = [rows[0]]\n",
 368       "up_rows = []\n",
 369       "for i in range(1, height-1):\n",
 370       "    down_rows += [''.join([c for n, c in enumerate(rows[i]) if n % 2 == 0])]\n",
 371       "    up_rows += [''.join([c for n, c in enumerate(rows[i]) if n % 2 == 1])]\n",
 372       "down_rows += [rows[-1]]\n",
 373       "down_rows, up_rows"
 374      ],
 375      "language": "python",
 376      "metadata": {},
 377      "outputs": [
 378       {
 379        "metadata": {},
 380        "output_type": "pyout",
 381        "prompt_number": 208,
 382        "text": [
 383         "(['harsetle', 'evtaoefr', 'lailfses', 'lseottn', 'otsneic', 'tmtgxne'],\n",
 384         " ['eaicrih', 'reseoap', 'ehiifri', 'hehptgc'])"
 385        ]
 386       }
 387      ],
 388      "prompt_number": 208
 389     },
 390     {
 391      "cell_type": "code",
 392      "collapsed": false,
 393      "input": [
 394       "up_rows.reverse()\n",
 395       "down_rows + up_rows"
 396      ],
 397      "language": "python",
 398      "metadata": {},
 399      "outputs": [
 400       {
 401        "metadata": {},
 402        "output_type": "pyout",
 403        "prompt_number": 164,
 404        "text": [
 405         "['hresleogcs',\n",
 406         " 'eehtoorre',\n",
 407         " 'laehnftac',\n",
 408         " 'lvaigteii',\n",
 409         " 'oarspeslp',\n",
 410         " 'tstiixtfh',\n",
 411         " 'htisetiee',\n",
 412         " 'emeacfnnr']"
 413        ]
 414       }
 415      ],
 416      "prompt_number": 164
 417     },
 418     {
 419      "cell_type": "code",
 420      "collapsed": false,
 421      "input": [
 422       "''.join(c for r in zip_longest(*(down_rows + up_rows), fillvalue='') for c in r)"
 423      ],
 424      "language": "python",
 425      "metadata": {},
 426      "outputs": [
 427       {
 428        "metadata": {},
 429        "output_type": "pyout",
 430        "prompt_number": 165,
 431        "text": [
 432         "'hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers'"
 433        ]
 434       }
 435      ],
 436      "prompt_number": 165
 437     },
 438     {
 439      "cell_type": "code",
 440      "collapsed": false,
 441      "input": [
 442       "def rfe(message, height, fillvalue=''):\n",
 443       "    sections = chunks(message, (height - 1) * 2, fillvalue=fillvalue)\n",
 444       "    n_sections = len(sections)\n",
 445       "    # Add the top row\n",
 446       "    rows = [''.join([s[0] for s in sections])]\n",
 447       "    # process the middle rows of the grid\n",
 448       "    for r in range(1, height-1):\n",
 449       "        rows += [''.join([s[r:r+1] + s[height*2-r-2:height*2-r-1] for s in sections])]\n",
 450       "    # process the bottom row\n",
 451       "    rows += [''.join([s[height - 1:height] for s in sections])]\n",
 452       "    # rows += [' '.join([s[height - 1] for s in sections])]\n",
 453       "    return ''.join(rows)"
 454      ],
 455      "language": "python",
 456      "metadata": {},
 457      "outputs": [],
 458      "prompt_number": 171
 459     },
 460     {
 461      "cell_type": "code",
 462      "collapsed": false,
 463      "input": [
 464       "rfe(pt, 5)"
 465      ],
 466      "language": "python",
 467      "metadata": {},
 468      "outputs": [
 469       {
 470        "metadata": {},
 471        "output_type": "pyout",
 472        "prompt_number": 177,
 473        "text": [
 474         "'hresleogcseeemhetaocofrnrnerlhateihsnefttiaeceltvsatiigitxetifihoarspeslp'"
 475        ]
 476       }
 477      ],
 478      "prompt_number": 177
 479     },
 480     {
 481      "cell_type": "code",
 482      "collapsed": false,
 483      "input": [
 484       "rfe(pt, 5) == ct"
 485      ],
 486      "language": "python",
 487      "metadata": {},
 488      "outputs": [
 489       {
 490        "metadata": {},
 491        "output_type": "pyout",
 492        "prompt_number": 178,
 493        "text": [
 494         "True"
 495        ]
 496       }
 497      ],
 498      "prompt_number": 178
 499     },
 500     {
 501      "cell_type": "code",
 502      "collapsed": false,
 503      "input": [
 504       "def rfd(message, height, fillvalue=''):\n",
 505       "    n_sections = math.ceil(len(message) / ((height - 1) * 2))\n",
 506       "    padding_to_add = n_sections * (height - 1) * 2 - len(message)\n",
 507       "    row_lengths = [n_sections] * (height - 1) * 2\n",
 508       "    for i in range((height - 1) * 2 - 1, (height - 1) * 2 - (padding_to_add + 1), -1):\n",
 509       "        row_lengths[i] -= 1\n",
 510       "    folded_row_lengths = [row_lengths[0]]\n",
 511       "    for i in range(1, height-1):\n",
 512       "        folded_row_lengths += [row_lengths[i] + row_lengths[-i]]\n",
 513       "    folded_row_lengths += [row_lengths[height - 1]]\n",
 514       "    rows = []\n",
 515       "    row_start = 0\n",
 516       "    for i in folded_row_lengths:\n",
 517       "        rows += [message[row_start:row_start + i]]\n",
 518       "        row_start += i\n",
 519       "    down_rows = [rows[0]]\n",
 520       "    up_rows = []\n",
 521       "    for i in range(1, height-1):\n",
 522       "        down_rows += [''.join([c for n, c in enumerate(rows[i]) if n % 2 == 0])]\n",
 523       "        up_rows += [''.join([c for n, c in enumerate(rows[i]) if n % 2 == 1])]\n",
 524       "    down_rows += [rows[-1]]\n",
 525       "    up_rows.reverse()\n",
 526       "    return ''.join(c for r in zip_longest(*(down_rows + up_rows), fillvalue='') for c in r)"
 527      ],
 528      "language": "python",
 529      "metadata": {},
 530      "outputs": [],
 531      "prompt_number": 220
 532     },
 533     {
 534      "cell_type": "code",
 535      "collapsed": false,
 536      "input": [
 537       "h = 7\n",
 538       "print(rfe(pt, h))\n",
 539       "rfd(rfe(pt, h), h)"
 540      ],
 541      "language": "python",
 542      "metadata": {},
 543      "outputs": [
 544       {
 545        "output_type": "stream",
 546        "stream": "stdout",
 547        "text": [
 548         "haspolsevsetgifrifrlatihnettaeelemtiocxernhorersleesgcptehaiaottneihesfic\n"
 549        ]
 550       },
 551       {
 552        "metadata": {},
 553        "output_type": "pyout",
 554        "prompt_number": 221,
 555        "text": [
 556         "'hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers'"
 557        ]
 558       }
 559      ],
 560      "prompt_number": 221
 561     },
 562     {
 563      "cell_type": "code",
 564      "collapsed": false,
 565      "input": [
 566       "for h in range(2, 51):\n",
 567       "    assert rfd(rfe(pt, h), h) == pt\n",
 568       "    print(h, ':', rfd(rfe(pt, h), h) == pt)"
 569      ],
 570      "language": "python",
 571      "metadata": {},
 572      "outputs": [
 573       {
 574        "output_type": "stream",
 575        "stream": "stdout",
 576        "text": [
 577         "2 : True\n",
 578         "3 : True\n",
 579         "4 : True\n",
 580         "5 : True\n",
 581         "6 : True\n",
 582         "7 : True\n",
 583         "8 : True\n",
 584         "9 : True\n",
 585         "10 : True\n",
 586         "11 : True\n",
 587         "12 : True\n",
 588         "13 : True\n",
 589         "14 : True\n",
 590         "15 : True\n",
 591         "16 : True\n",
 592         "17 : True\n",
 593         "18 : True\n",
 594         "19 : True\n",
 595         "20 : True\n",
 596         "21 : True\n",
 597         "22 : True\n",
 598         "23 : True\n",
 599         "24 : True\n",
 600         "25 : True\n",
 601         "26 : True\n",
 602         "27 : True\n",
 603         "28 : True\n",
 604         "29 : True\n",
 605         "30 : True\n",
 606         "31 : True\n",
 607         "32 : True\n",
 608         "33 : True\n",
 609         "34 : True\n",
 610         "35 : True\n",
 611         "36 : True\n",
 612         "37 : True\n",
 613         "38 : True\n",
 614         "39 : True\n",
 615         "40 : True\n",
 616         "41 : True\n",
 617         "42 : True\n",
 618         "43 : True\n",
 619         "44 : True\n",
 620         "45 : True\n",
 621         "46 : True\n",
 622         "47 : True\n",
 623         "48 : True\n",
 624         "49 : True\n",
 625         "50 : True\n"
 626        ]
 627       }
 628      ],
 629      "prompt_number": 227
 630     },
 631     {
 632      "cell_type": "code",
 633      "collapsed": false,
 634      "input": [
 635       "h"
 636      ],
 637      "language": "python",
 638      "metadata": {},
 639      "outputs": [
 640       {
 641        "metadata": {},
 642        "output_type": "pyout",
 643        "prompt_number": 224,
 644        "text": [
 645         "1"
 646        ]
 647       }
 648      ],
 649      "prompt_number": 224
 650     },
 651     {
 652      "cell_type": "code",
 653      "collapsed": false,
 654      "input": [
 655       "rfe('hellotherefriends', 4)"
 656      ],
 657      "language": "python",
 658      "metadata": {},
 659      "outputs": [
 660       {
 661        "metadata": {},
 662        "output_type": "pyout",
 663        "prompt_number": 228,
 664        "text": [
 665         "'hhieterelorfnsled'"
 666        ]
 667       }
 668      ],
 669      "prompt_number": 228
 670     },
 671     {
 672      "cell_type": "code",
 673      "collapsed": false,
 674      "input": [
 675       "rfd('hhieterelorfnsled', 4)"
 676      ],
 677      "language": "python",
 678      "metadata": {},
 679      "outputs": [
 680       {
 681        "metadata": {},
 682        "output_type": "pyout",
 683        "prompt_number": 229,
 684        "text": [
 685         "'hellotherefriends'"
 686        ]
 687       }
 688      ],
 689      "prompt_number": 229
 690     },
 691     {
 692      "cell_type": "code",
 693      "collapsed": false,
 694      "input": [
 695       "for h in [3, 5, 7]:\n",
 696       "    print(rfe(pt, h))"
 697      ],
 698      "language": "python",
 699      "metadata": {},
 700      "outputs": [
 701       {
 702        "output_type": "stream",
 703        "stream": "stdout",
 704        "text": [
 705         "horaersslpeeosglcpselteevsmhatetiiaogicotxfretnrifneihrlhateihsnefttiaece\n",
 706         "hresleogcseeemhetaocofrnrnerlhateihsnefttiaeceltvsatiigitxetifihoarspeslp\n",
 707         "haspolsevsetgifrifrlatihnettaeelemtiocxernhorersleesgcptehaiaottneihesfic\n"
 708        ]
 709       }
 710      ],
 711      "prompt_number": 230
 712     },
 713     {
 714      "cell_type": "code",
 715      "collapsed": false,
 716      "input": [],
 717      "language": "python",
 718      "metadata": {},
 719      "outputs": []
 720     }
 721    ],
 722    "metadata": {}
 723   }
 724  ]
 725 }