Class: Twofish

Inherits:

Object

Object
Twofish

Defined in:: lib/twofish.rb,
lib/twofish/mode.rb,
lib/twofish/padding.rb

Overview

twofish.rb

Author: Martin Carpenter
Email: [email protected]
Copyright: Copyright © Martin Carpenter 2009

Implements a class for symmetric encryption using the Twofish encryption algorithm based on original work by Guido Flohr.

Defined Under Namespace

Modules: Mode, Padding

Constant Summary collapse

BLOCK_SIZE = The block size in bytes (16).

Q0 = :stopdoc:

[
  169, 103, 179, 232, 4,   253, 163, 118, 154, 146, 128, 120, 228,
  221, 209, 56,  13,  198, 53,  152, 24,  247, 236, 108, 67,  117,
  55,  38,  250, 19,  148, 72,  242, 208, 139, 48,  132, 84,  223,
  35,  25,  91,  61,  89,  243, 174, 162, 130, 99,  1,   131, 46,
  217, 81,  155, 124, 166, 235, 165, 190, 22,  12,  227, 97,  192,
  140, 58,  245, 115, 44,  37,  11,  187, 78,  137, 107, 83,  106,
  180, 241, 225, 230, 189, 69,  226, 244, 182, 102, 204, 149, 3,
  86,  212, 28,  30,  215, 251, 195, 142, 181, 233, 207, 191, 186,
  234, 119, 57,  175, 51,  201, 98,  113, 129, 121, 9,   173, 36,
  205, 249, 216, 229, 197, 185, 77,  68,  8,   134, 231, 161, 29,
  170, 237, 6,   112, 178, 210, 65,  123, 160, 17,  49,  194, 39,
  144, 32,  246, 96,  255, 150, 92,  177, 171, 158, 156, 82,  27,
  95,  147, 10,  239, 145, 133, 73,  238, 45,  79,  143, 59,  71,
  135, 109, 70,  214, 62,  105, 100, 42,  206, 203, 47,  252, 151,
  5,   122, 172, 127, 213, 26,  75,  14,  167, 90,  40,  20,  63,
  41,  136, 60,  76,  2,   184, 218, 176, 23,  85,  31, 138,  125,
  87,  199, 141, 116, 183, 196, 159, 114, 126, 21,  34,  18,  88,
  7,   153, 52,  110, 80,  222, 104, 101, 188, 219, 248, 200, 168,
  43,  64,  220, 254, 50,  164, 202, 16,  33,  240, 211, 93,  15,
  0,   111, 157, 54,  66,  74,  94,  193, 224
]

Q1 =

[
  117, 243, 198, 244, 219, 123, 251, 200, 74,  211, 230, 107, 69,
  125, 232, 75,  214, 50,  216, 253, 55,  113, 241, 225, 48,  15,
  248, 27,  135, 250, 6,   63,  94,  186, 174, 91,  138, 0,   188,
  157, 109, 193, 177, 14,  128, 93,  210, 213, 160, 132, 7,   20,
  181, 144, 44,  163, 178, 115, 76,  84,  146, 116, 54,  81,  56,
  176, 189, 90,  252, 96,  98,  150, 108, 66,  247, 16,  124, 40,
  39,  140, 19,  149, 156, 199, 36,  70,  59,  112, 202, 227, 133,
  203, 17,  208, 147, 184, 166, 131, 32,  255, 159, 119, 195, 204,
  3,   111, 8,   191, 64,  231, 43,  226, 121, 12,  170, 130, 65,
  58,  234, 185, 228, 154, 164, 151, 126, 218, 122, 23,  102, 148,
  161, 29,  61,  240, 222, 179, 11,  114, 167, 28,  239, 209, 83,
  62,  143, 51,  38,  95,  236, 118, 42,  73,  129, 136, 238, 33,
  196, 26,  235, 217, 197, 57,  153, 205, 173, 49,  139, 1,   24,
  35,  221, 31,  78,  45,  249, 72,  79,  242, 101, 142, 120, 92,
  88,  25,  141, 229, 152, 87,  103, 127, 5,   100, 175, 99,  182,
  254, 245, 183, 60,  165, 206, 233, 104, 68,  224, 77,  67,  105,
  41,  46,  172, 21,  89,  168, 10,  158, 110, 71,  223, 52,  53,
  106, 207, 220, 34,  201, 192, 155, 137, 212, 237, 171, 18,  162,
  13,  82,  187, 2,   47,  169, 215, 97,  30,  180, 80,  4,   246,
  194, 22, 37,  134, 86,  85,  9,   190, 145
]

M0 =

[
  3166450293, 3974898163, 538985414,  3014904308, 3671720923,
  33721211,   3806473211, 2661219016, 3385453642, 3570665939,
  404253670,  505323371,  2560101957, 2998024317, 2795950824,
  640071499,  1010587606, 2475919922, 2189618904, 1381144829,
  2071712823, 3149608817, 1532729329, 1195869153, 606354480,
  1364320783, 3132802808, 1246425883, 3216984199, 218984698,
  2964370182, 1970658879, 3537042782, 2105352378, 1717973422,
  976921435,  1499012234, 0,          3452801980, 437969053,
  2930650221, 2139073473, 724289457,  3200170254, 3772817536,
  2324303965, 993743570,  1684323029, 3638069408, 3890718084,
  1600120839, 454758676,  741130933,  4244419728, 825304876,
  2155898275, 1936927410, 202146163,  2037997388, 1802191188,
  1263207058, 1397975412, 2492763958, 2206408529, 707409464,
  3301219504, 572704957,  3587569754, 3183330300, 1212708960,
  4294954594, 1280051094, 1094809452, 3351766594, 3958056183,
  471602192,  1566401404, 909517352,  1734852647, 3924406156,
  1145370899, 336915093,  4126522268, 3486456007, 1061104932,
  3233866566, 1920129851, 1414818928, 690572490,  4042274275,
  134807173,  3334870987, 4092808977, 2358043856, 2762234259,
  3402274488, 1751661478, 3099086211, 943204384,  3857002239,
  2913818271, 185304183,  3368558019, 2577006540, 1482222851,
  421108335,  235801096,  2509602495, 1886408768, 4160172263,
  1852755755, 522153698,  3048553849, 151588620,  1633760426,
  1465325186, 2678000449, 2644344890, 286352618,  623234489,
  2947538404, 1162152090, 3755969956, 2745392279, 3941258622,
  892688602,  3991785594, 1128528919, 4177054566, 4227576212,
  926405537,  4210704413, 3267520573, 3031747824, 842161630,
  2627498419, 1448535819, 3823360626, 2273796263, 353704732,
  4193860335, 1667481553, 875866451,  2593817918, 2981184143,
  2088554803, 2290653990, 1027450463, 2711738348, 3840204662,
  2172752938, 2442199369, 252705665,  4008618632, 370565614,
  3621221153, 2543318468, 2779097114, 4278075371, 1835906521,
  2021174981, 3318050105, 488498585,  1987486925, 1044307117,
  3419105073, 3065399179, 4025441025, 303177240,  1616954659,
  1785376989, 1296954911, 3469666638, 3739122733, 1431674361,
  2122209864, 555856463,  50559730,   2694850149, 1583225230,
  1515873912, 1701137244, 1650609752, 4261233945, 101119117,
  1077970661, 4075994776, 859024471,  387420263,  84250239,
  3907542533, 1330609508, 2307484335, 269522275,  1953771446,
  168457726,  1549570805, 2610656439, 757936956,  808507045,
  774785486,  1229556201, 1179021928, 2004309316, 2829637856,
  2526413901, 673758531,  2846435689, 3654908201, 2256965934,
  3520169900, 4109650453, 2374833497, 3604382376, 3115957258,
  1111625118, 4143366510, 791656519,  3722249951, 589510964,
  3435946549, 4059153514, 3250655951, 2240146396, 2408554018,
  1903272393, 2425417920, 2863289243, 16904585,   2341200340,
  1313770733, 2391699371, 2880152082, 1869561506, 3873854477,
  3688624722, 2459073467, 3082270210, 1768540719, 960092585,
  3553823959, 2812748641, 2728570142, 3284375988, 1819034704,
  117900548,  67403766,   656885442,  2896996118, 3503322661,
  1347425158, 3705468758, 2223250005, 3789639945, 2054825406,
  320073617
]

M1 =

[
  2849585465, 1737496343, 3010567324, 3906119334, 67438343,
  4254618194, 2741338240, 1994384612, 2584233285, 2449623883,
  2158026976, 2019973722, 3839733679, 3719326314, 3518980963,
  943073834,  223667942,  3326287904, 895667404,  2562650866,
  404623890,  4146392043, 3973554593, 1819754817, 1136470056,
  1966259388, 936672123,  647727240,  4201647373, 335103044,
  2494692347, 1213890174, 4068082435, 3504639116, 2336732854,
  809247780,  2225465319, 1413573483, 3741769181, 600137824,
  424017405,  1537423930, 1030275778, 1494584717, 4079086828,
  2922473062, 2722000751, 2182502231, 1670713360, 22802415,
  2202908856, 781289094,  3652545901, 1361019779, 2605951658,
  2086886749, 2788911208, 3946839806, 2782277680, 3190127226,
  380087468,  202311945,  3811963120, 1629726631, 3236991120,
  2360338921, 981507485,  4120009820, 1937837068, 740766001,
  628543696,  199710294,  3145437842, 1323945678, 2314273025,
  1805590046, 1403597876, 1791291889, 3029976003, 4053228379,
  3783477063, 3865778200, 3184009762, 1158584472, 3798867743,
  4106859443, 3056563316, 1724643576, 3439303065, 2515145748,
  65886296,   1459084508, 3571551115, 471536917,  514695842,
  3607942099, 4213957346, 3273509064, 2384027230, 3049401388,
  3918088521, 3474112961, 3212744085, 3122691453, 3932426513,
  2005142283, 963495365,  2942994825, 869366908,  3382800753,
  1657733119, 1899477947, 2180714255, 2034087349, 156361185,
  2916892222, 606945087,  3450107510, 4187837781, 3639509634,
  3850780736, 3316545656, 3117229349, 1292146326, 1146451831,
  134876686,  2249412688, 3878746103, 2714974007, 490797818,
  2855559521, 3985395278, 112439472,  1886147668, 2989126515,
  3528604475, 1091280799, 2072707586, 2693322968, 290452467,
  828885963,  3259377447, 666920807,  2427780348, 539506744,
  4135519236, 1618495560, 4281263589, 2517060684, 1548445029,
  2982619947, 2876214926, 2651669058, 2629563893, 1391647707,
  468929098,  1604730173, 2472125604, 180140473,  4013619705,
  2448364307, 2248017928, 1224839569, 3999340054, 763158238,
  1337073953, 2403512753, 1004237426, 1203253039, 2269691839,
  1831644846, 1189331136, 3596041276, 1048943258, 1764338089,
  1685933903, 714375553,  3460902446, 3407333062, 801794409,
  4240686525, 2539430819, 90106088,   2060512749, 2894582225,
  2140013829, 3585762404, 447260069,  1270294054, 247054014,
  2808121223, 1526257109, 673330742,  336665371,  1071543669,
  695851481,  2292903662, 1009986861, 1281325433, 45529015,
  3096890058, 3663213877, 2963064004, 402408259,  1427801220,
  536235341,  2317113689, 2100867762, 1470903091, 3340292047,
  2381579782, 1953059667, 3077872539, 3304429463, 2673257901,
  1926947811, 2127948522, 357233908,  580816783,  312650667,
  1481532002, 132669279,  2581929245, 876159779,  1858205430,
  1346661484, 3730649650, 1752319558, 1697030304, 3163803085,
  3674462938, 4173773498, 3371867806, 2827146966, 735014510,
  1079013488, 3706422661, 4269083146, 847942547,  2760761311,
  3393988905, 269753372,  561240023,  4039947444, 3540636884,
  1561365130, 266490193,  0,          1872369945, 2648709658,
  915379348,  1122420679, 1257032137, 1593692882, 3249241983,
  3772295336
]

M2 =

[
  3161832498, 3975408673, 549855299,  3019158473, 3671841283,
  41616011,   3808158251, 2663948026, 3377121772, 3570652169,
  417732715,  510336671,  2554697742, 2994582072, 2800264914,
  642459319,  1020673111, 2469565322, 2195227374, 1392333464,
  2067233748, 3144792887, 1542544279, 1205946243, 607134780,
  1359958498, 3136862918, 1243302643, 3213344584, 234491248,
  2953228467, 1967093214, 3529429757, 2109373728, 1722705457,
  979057315,  1502239004, 0,          3451702675, 446503648,
  2926423596, 2143387563, 733031367,  3188637369, 3766542496,
  2321386000, 1003633490, 1691706554, 3634419848, 3884246949,
  1594318824, 454302481,  750070978,  4237360308, 824979751,
  2158198885, 1941074730, 208866433,  2035054943, 1800694593,
  1267878658, 1400132457, 2486604943, 2203157279, 708323894,
  3299919004, 582820552,  3579500024, 3187457475, 1214269560,
  4284678094, 1284918279, 1097613687, 3343042534, 3958893348,
  470817812,  1568431459, 908604962,  1730635712, 3918326191,
  1142113529, 345314538,  4120704443, 3485978392, 1059340077,
  3225862371, 1916498651, 1416647788, 701114700,  4041470005,
  142936318,  3335243287, 4078039887, 2362477796, 2761139289,
  3401108118, 1755736123, 3095640141, 941635624,  3858752814,
  2912922966, 192351108,  3368273949, 2580322815, 1476614381,
  426711450,  235408906,  2512360830, 1883271248, 4159174448,
  1848340175, 534912878,  3044652349, 151783695,  1638555956,
  1468159766, 2671877899, 2637864320, 300552548,  632890829,
  2951000029, 1167738120, 3752124301, 2744623964, 3934186197,
  903492952,  3984256464, 1125598204, 4167497931, 4220844977,
  933312467,  4196268608, 3258827368, 3035673804, 853422685,
  2629016689, 1443583719, 3815957466, 2275903328, 354161947,
  4193253690, 1674666943, 877868201,  2587794053, 2978984258,
  2083749073, 2284226715, 1029651878, 2716639703, 3832997087,
  2167046548, 2437517569, 260116475,  4001951402, 384702049,
  3609319283, 2546243573, 2769986984, 4276878911, 1842965941,
  2026207406, 3308897645, 496573925,  1993176740, 1051541212,
  3409038183, 3062609479, 4009881435, 303567390,  1612931269,
  1792895664, 1293897206, 3461271273, 3727548028, 1442403741,
  2118680154, 558834098,  66192250,   2691014694, 1586388505,
  1517836902, 1700554059, 1649959502, 4246338885, 109905652,
  1088766086, 4070109886, 861352876,  392632208,  92210574,
  3892701278, 1331974013, 2309982570, 274927765,  1958114351,
  184420981,  1559583890, 2612501364, 758918451,  816132310,
  785264201,  1240025481, 1181238898, 2000975701, 2833295576,
  2521667076, 675489981,  2842274089, 3643398521, 2251196049,
  3517763975, 4095079498, 2371456277, 3601389186, 3104487868,
  1117667853, 4134467265, 793194424,  3722435846, 590619449,
  3426077794, 4050317764, 3251618066, 2245821931, 2401406878,
  1909027233, 2428539120, 2862328403, 25756145,   2345962465,
  1324174988, 2393607791, 2870127522, 1872916286, 3859670612,
  3679640562, 2461766267, 3070408630, 1764714954, 967391705,
  3554136844, 2808194851, 2719916717, 3283403673, 1817209924,
  117704453,  83231871,   667035462,  2887167143, 3492139126,
  1350979603, 3696680183, 2220196890, 3775521105, 2059303461,
  328274927
]

M3 =

[
  3644434905, 2417452944, 1906094961, 3534153938, 84345861,
  2555575704, 1702929253, 3756291807, 138779144,  38507010,
  2699067552, 1717205094, 3719292125, 2959793584, 3210990015,
  908736566,  1424362836, 1126221379, 1657550178, 3203569854,
  504502302,  619444004,  3617713367, 2000776311, 3173532605,
  851211570,  3564845012, 2609391259, 1879964272, 4181988345,
  2986054833, 1518225498, 2047079034, 3834433764, 1203145543,
  1009004604, 2783413413, 1097552961, 115203846,  3311412165,
  1174214981, 2738510755, 1757560168, 361584917,  569176865,
  828812849,  1047503422, 374833686,  2500879253, 1542390107,
  1303937869, 2441490065, 3043875253, 528699679,  1403689811,
  1667071075, 996714043,  1073670975, 3593512406, 628801061,
  2813073063, 252251151,  904979253,  598171939,  4036018416,
  2951318703, 2157787776, 2455565714, 2165076865, 657533991,
  1993352566, 3881176039, 2073213819, 3922611945, 4043409905,
  2669570975, 2838778793, 3304155844, 2579739801, 2539385239,
  2202526083, 1796793963, 3357720008, 244860174,  1847583342,
  3384014025, 796177967,  3422054091, 4288269567, 3927217642,
  3981968365, 4158412535, 3784037601, 454368283,  2913083053,
  215209740,  736295723,  499696413,  425627161,  3257710018,
  2303322505, 314691346,  2123743102, 545110560,  1678895716,
  2215344004, 1841641837, 1787408234, 3514577873, 2708588961,
  3472843470, 935031095,  4212097531, 1035303229, 1373702481,
  3695095260, 759112749,  2759249316, 2639657373, 4001552622,
  2252400006, 2927150510, 3441801677, 76958980,   1433879637,
  168691722,  324044307,  821552944,  3543638483, 1090133312,
  878815796,  2353982860, 3014657715, 1817473132, 712225322,
  1379652178, 194986251,  2332195723, 2295898248, 1341329743,
  1741369703, 1177010758, 3227985856, 3036450996, 674766888,
  2131031679, 2018009208, 786825006,  122459655,  1264933963,
  3341529543, 1871620975, 222469645,  3153435835, 4074459890,
  4081720307, 2789040038, 1503957849, 3166243516, 989458234,
  4011037167, 4261971454, 26298625,   1628892769, 2094935420,
  2988527538, 1118932802, 3681696731, 3090106296, 1220511560,
  749628716,  3821029091, 1463604823, 2241478277, 698968361,
  2102355069, 2491493012, 1227804233, 398904087,  3395891146,
  3284008131, 1554224988, 1592264030, 3505224400, 2278665351,
  2382725006, 3127170490, 2829392552, 3072740279, 3116240569,
  1619502944, 4174732024, 573974562,  286987281,  3732226014,
  2044275065, 2867759274, 858602547,  1601784927, 3065447094,
  2529867926, 1479924312, 2630135964, 4232255484, 444880154,
  4132249590, 475630108,  951221560,  2889045932, 416270104,
  4094070260, 1767076969, 1956362100, 4120364277, 1454219094,
  3672339162, 3588914901, 1257510218, 2660180638, 2729120418,
  1315067982, 3898542056, 3843922405, 958608441,  3254152897,
  1147949124, 1563614813, 1917216882, 648045862,  2479733907,
  64674563,   3334142150, 4204710138, 2195105922, 3480103887,
  1349533776, 3951418603, 1963654773, 2324902538, 2380244109,
  1277807180, 337383444,  1943478643, 3434410188, 164942601,
  277503248,  3796963298, 0,          2585358234, 3759840736,
  2408855183, 3871818470, 3972614892, 4258422525, 2877276587,
  3634946264
]

Instance Attribute Summary collapse

#iv ⇒ Object

Initialization vector for CBC mode.
#key_size ⇒ Object readonly

The size of the key in bytes (16, 24, 32 bytes).
#mode ⇒ Object

Encryption mode eg Mode::ECB (default) or Mode::CBC.
#padding ⇒ Object

Padding algorithm eg Padding::NONE (default) or Padding::ZERO_BYTE.

Class Method Summary collapse

.block_size ⇒ Object

Return the cipher’s block size in bytes.

Instance Method Summary collapse

#decrypt(ciphertext) ⇒ Object

Decrypt a ciphertext string, unchunking as required for chaining modes.
#decrypt_block(plain) ⇒ Object

Decrypt a single block (16 bytes).
#encrypt(plaintext) ⇒ Object

Encrypt a plaintext string, chunking as required for CBC mode.
#encrypt_block(plain_text) ⇒ Object

Encrypt a single block (16 bytes).
#initialize(key_string, opts = {}) ⇒ Twofish constructor

Takes a mandatory key (16, 24 or 32 bytes), and an options hash as follows: :mode => :ecb (default) or :cbc :iv => optional 16 byte initialization vector (randomly generated if not supplied) :padding => :none (default), :zero_byte, :iso10126_2 or :pkcs7.
#reset! ⇒ Object

Reset the cipher state (for feedback modes).
#xor_block!(target, source) ⇒ Object

Exclusive-or two blocks together, byte-by-byte, storing the result in the first block.

Constructor Details

#initialize(key_string, opts = {}) ⇒ `Twofish`

Takes a mandatory key (16, 24 or 32 bytes), and an options hash as follows:

:mode => :ecb (default) or :cbc
:iv => optional 16 byte initialization vector (randomly generated if not supplied)
:padding => :none (default), :zero_byte, :iso10126_2 or :pkcs7

# File 'lib/twofish.rb', line 306

def initialize(key_string, opts={})

  self.mode = opts[:mode] # use setter for validation
  self.padding = opts[:padding] # use setter for validation
  @iv = opts[:iv] || SecureRandom.random_bytes(BLOCK_SIZE) unless @mode == Mode::ECB

  # The key consists of k=len/8 (2, 3 or 4) 64-bit units.
  key = key_string.unpack("C*")
  @key_size = key.length

  # We must derive three vectors Me, Mo, and S, each with k 32-bit
  # words, from the 2k words in the key.
  #
  #       Me = (key[0], key[2], ..., key[2k-2]) (even words)
  #       Mo = (key[1], key[3], ..., key[2k-1]) (odd  words)
  #
  # The third vector is derived by multiplying each of the k groups
  # of 8 bytes from the key by a 4x8 matrix, to get k 32-bit words.
  #
  #       S = (S[k-1], S[k-2], ..., S[0])
  #
  # where S[i] are the 4 bytes from the multiplication, interpreted
  # as a 32-bit word. As described later, mds_rem is equivalent to
  # the matrix multiplication, but faster.
  le_longs = key_string.unpack("V*")

  # The words of the expanded key K are defined using the h function:
  #
  #       rho     = 2^24 + 2^16 + 2^8 + 2^0 (0x01010101)
  #       A[i]    = h(2i*rho, Me)
  #       B[i]    = ROL(h(2(i+1)*rho, Mo), 8)
  #       K[2i]   = (A[i] + B[i]) mod 2^32
  #       K[2i+1] = ROL((A[i] + 2B[i]) mod 2^32, 9)
  #
  # rho has the property that, for i = 0..255, the word i*rho
  # consists of four equal bytes, each with the value i. The function
  # h is only applied to words of this type, so we only pass it the
  # value of i.
  @k = []

  # The key-dependent S-boxes used in the g() function are created
  # below. They are defined by g(X) = h(X, S), where S is the vector
  # derived from the key. That is, for i=0..3, the S-box S[i] is
  # formed by mapping from x[i] to y[i] in the h function.
  #
  # The relevant lookup tables qN have been precomputed and stored in
  # tables.h; we also perform full key precomputations incorporating
  # the MDS matrix multiplications.
  @xS0, @xS1, @xS2, @xS3 = [], [], [], []
  case @key_size
  when 16
    s7, s6, s5, s4 = *mds_rem(le_longs[0], le_longs[1])
    s3, s2, s1, s0 = *mds_rem(le_longs[2], le_longs[3])
    (0..38).step(2) do |i|
      j = i + 1
      a = M0[Q0[Q0[i] ^ key[8]]  ^ key[0]] ^
          M1[Q0[Q1[i] ^ key[9]]  ^ key[1]] ^
          M2[Q1[Q0[i] ^ key[10]] ^ key[2]] ^
          M3[Q1[Q1[i] ^ key[11]] ^ key[3]]
      b = M0[Q0[Q0[j] ^ key[12]] ^ key[4]] ^
          M1[Q0[Q1[j] ^ key[13]] ^ key[5]] ^
          M2[Q1[Q0[j] ^ key[14]] ^ key[6]] ^
          M3[Q1[Q1[j] ^ key[15]] ^ key[7]]
      b = ((b & 0xffffff) << 8) | (b >> 24)
      a = 0xffffffff & (a+b)
      @k.push(a)
      a = 0xffffffff & (a+b)
      @k.push((a & 0x7fffff) << 9 | a >> 23)
    end
    (0..255).each do |i|
      @xS0[i] = M0[Q0[Q0[i] ^ s4] ^ s0]
      @xS1[i] = M1[Q0[Q1[i] ^ s5] ^ s1]
      @xS2[i] = M2[Q1[Q0[i] ^ s6] ^ s2]
      @xS3[i] = M3[Q1[Q1[i] ^ s7] ^ s3]
    end
  when 24
    sb, sa, s9, s8 = *mds_rem(le_longs[0], le_longs[1])
    s7, s6, s5, s4 = *mds_rem(le_longs[2], le_longs[3])
    s3, s2, s1, s0 = *mds_rem(le_longs[4], le_longs[5])
    (0..38).step(2) do |i|
      j = i + 1
      a = M0[Q0[Q0[Q1[i] ^ key[16]] ^ key[8]]  ^ key[0]] ^
          M1[Q0[Q1[Q1[i] ^ key[17]] ^ key[9]]  ^ key[1]] ^
          M2[Q1[Q0[Q0[i] ^ key[18]] ^ key[10]] ^ key[2]] ^
          M3[Q1[Q1[Q0[i] ^ key[19]] ^ key[11]] ^ key[3]]
      b = M0[Q0[Q0[Q1[j] ^ key[20]] ^ key[12]] ^ key[4]] ^
          M1[Q0[Q1[Q1[j] ^ key[21]] ^ key[13]] ^ key[5]] ^
          M2[Q1[Q0[Q0[j] ^ key[22]] ^ key[14]] ^ key[6]] ^
          M3[Q1[Q1[Q0[j] ^ key[23]] ^ key[15]] ^ key[7]]
      b = ((b & 0xffffff) << 8) | (b >> 24)
      a = 0xffffffff & (a+b)
      @k.push(a)
      a = 0xffffffff & (a+b)
      @k.push((a & 0x7fffff) << 9 | a >> 23)
    end
    (0..255).each do |i|
      @xS0[i] = M0[Q0[Q0[Q1[i] ^ s8] ^ s4] ^ s0]
      @xS1[i] = M1[Q0[Q1[Q1[i] ^ s9] ^ s5] ^ s1]
      @xS2[i] = M2[Q1[Q0[Q0[i] ^ sa] ^ s6] ^ s2]
      @xS3[i] = M3[Q1[Q1[Q0[i] ^ sb] ^ s7] ^ s3]
    end
  when 32
    sf, se, sd, sc = *mds_rem(le_longs[0], le_longs[1])
    sb, sa, s9, s8 = *mds_rem(le_longs[2], le_longs[3])
    s7, s6, s5, s4 = *mds_rem(le_longs[4], le_longs[5])
    s3, s2, s1, s0 = *mds_rem(le_longs[6], le_longs[7])
    (0..38).step(2) do |i|
      j = i + 1
      a = M0[Q0[Q0[Q1[Q1[i] ^ key[24]] ^ key[16]] ^ key[8]]  ^ key[0]] ^
          M1[Q0[Q1[Q1[Q0[i] ^ key[25]] ^ key[17]] ^ key[9]]  ^ key[1]] ^
          M2[Q1[Q0[Q0[Q0[i] ^ key[26]] ^ key[18]] ^ key[10]] ^ key[2]] ^
          M3[Q1[Q1[Q0[Q1[i] ^ key[27]] ^ key[19]] ^ key[11]] ^ key[3]]
      b = M0[Q0[Q0[Q1[Q1[j] ^ key[28]] ^ key[20]] ^ key[12]] ^ key[4]] ^
          M1[Q0[Q1[Q1[Q0[j] ^ key[29]] ^ key[21]] ^ key[13]] ^ key[5]] ^
          M2[Q1[Q0[Q0[Q0[j] ^ key[30]] ^ key[22]] ^ key[14]] ^ key[6]] ^
          M3[Q1[Q1[Q0[Q1[j] ^ key[31]] ^ key[23]] ^ key[15]] ^ key[7]]
      b = ((b & 0xffffff) << 8) | (b >> 24)
      a = 0xffffffff & (a+b)
      @k.push(a)
      a = 0xffffffff & (a+b)
      @k.push((a & 0x7fffff) << 9 | a >> 23)
    end
    (0..255).each do |i|
      @xS0[i] = M0[Q0[Q0[Q1[Q1[i]^sc]^s8]^s4]^s0]
      @xS1[i] = M1[Q0[Q1[Q1[Q0[i]^sd]^s9]^s5]^s1]
      @xS2[i] = M2[Q1[Q0[Q0[Q0[i]^se]^sa]^s6]^s2]
      @xS3[i] = M3[Q1[Q1[Q0[Q1[i]^sf]^sb]^s7]^s3]
    end
  else
    raise ArgumentError, "invalid key length #{@key_size} (expecting 16, 24 or 32 bytes)"
  end

end

Instance Attribute Details

#iv ⇒ `Object`

Initialization vector for CBC mode.



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# File 'lib/twofish.rb', line 19

def iv
  @iv
end

#key_size ⇒ `Object` (readonly)

The size of the key in bytes (16, 24, 32 bytes).



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24

# File 'lib/twofish.rb', line 22

def key_size
  @key_size
end

#mode ⇒ `Object`

Encryption mode eg Mode::ECB (default) or Mode::CBC.



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# File 'lib/twofish.rb', line 25

def mode
  @mode
end

#padding ⇒ `Object`

Padding algorithm eg Padding::NONE (default) or Padding::ZERO_BYTE.



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# File 'lib/twofish.rb', line 28

def padding
  @padding
end

Class Method Details

.block_size ⇒ `Object`

Return the cipher’s block size in bytes.



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# File 'lib/twofish.rb', line 467

def self.block_size
  BLOCK_SIZE
end

Instance Method Details

#decrypt(ciphertext) ⇒ `Object`

Decrypt a ciphertext string, unchunking as required for chaining modes. If @iv is not set then we use the first block as the initialization vector when chaining.

Raises:

(ArgumentError)

# File 'lib/twofish.rb', line 492

def decrypt(ciphertext)
  ciphertext = ciphertext.dup.force_encoding('ASCII-8BIT')
  raise ArgumentError, "ciphertext is not a multiple of #{BLOCK_SIZE} bytes" unless (ciphertext.length % BLOCK_SIZE).zero?
  result = ''.force_encoding('ASCII-8BIT')
  if Mode::CBC == @mode
    if @iv
      @_feedback ||= @iv
    else
      @_feedback ||= ciphertext[0, BLOCK_SIZE]
      ciphertext = ciphertext[BLOCK_SIZE..-1]
    end
  end
  (0...ciphertext.length).step(BLOCK_SIZE) do |block_ptr|
    ciphertext_block = ciphertext[block_ptr, BLOCK_SIZE]
    plaintext_block = decrypt_block(ciphertext_block)
    xor_block!(plaintext_block, @_feedback) if Mode::CBC == @mode
    result << plaintext_block
    @_feedback = ciphertext_block
  end
  Padding.unpad!(result, BLOCK_SIZE, @padding)
end

#decrypt_block(plain) ⇒ `Object`

Decrypt a single block (16 bytes).

# File 'lib/twofish.rb', line 787

def decrypt_block(plain)

  words = plain.unpack("V4")

  r0 = @k[4] ^ words[0]
  r1 = @k[5] ^ words[1]
  r2 = @k[6] ^ words[2]
  r3 = @k[7] ^ words[3]

  # i = 7
  t0 = @xS0[r0 & 0xff] ^
       @xS1[r0 >> 8 & 0xff] ^
       @xS2[r0 >> 16 & 0xff] ^
       @xS3[r0 >> 24 & 0xff]
  t1 = @xS0[r1 >> 24 & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[r1 >> 8 & 0xff] ^
       @xS3[r1 >> 16 & 0xff]

  r2 = r2 >> 31 & 0x1 | (r2 & 0x7fffffff) << 1
  r2 ^= 0xffffffff & (t0 + t1 + @k[38])

  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[39])
  r3 = r3 >> 1 & 0x7fffffff | (r3 & 0x1) << 31

  t0 = @xS0[r2 & 0xff] ^
       @xS1[r2 >> 8 & 0xff] ^
       @xS2[r2 >> 16 & 0xff] ^
       @xS3[r2 >> 24 & 0xff]
  t1 = @xS0[r3 >> 24 & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[r3 >> 8 & 0xff] ^
       @xS3[r3 >> 16 & 0xff]

  r0 = r0 >> 31 & 0x1 | (r0 & 0x7fffffff) << 1
  r0 ^= 0xffffffff & (t0 + t1 + @k[36])

  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[37])
  r1 = r1 >> 1 & 0x7fffffff | (r1 & 0x1) << 31

  # i = 6
  t0 = @xS0[r0 & 0xff] ^
       @xS1[r0 >> 8 & 0xff] ^
       @xS2[r0 >> 16 & 0xff] ^
       @xS3[r0 >> 24 & 0xff]
  t1 = @xS0[r1 >> 24 & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[r1 >> 8 & 0xff] ^
       @xS3[r1 >> 16 & 0xff]

  r2 = r2 >> 31 & 0x1 | (r2 & 0x7fffffff) << 1
  r2 ^= 0xffffffff & (t0 + t1 + @k[34])

  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[35])
  r3 = r3 >> 1 & 0x7fffffff | (r3 & 0x1) << 31

  t0 = @xS0[r2 & 0xff] ^
       @xS1[r2 >> 8 & 0xff] ^
       @xS2[r2 >> 16 & 0xff] ^
       @xS3[r2 >> 24 & 0xff]
  t1 = @xS0[r3 >> 24 & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[r3 >> 8 & 0xff] ^
       @xS3[r3 >> 16 & 0xff]

  r0 = r0 >> 31 & 0x1 | (r0 & 0x7fffffff) << 1
  r0 ^= 0xffffffff & (t0 + t1 + @k[32])

  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[33])
  r1 = r1 >> 1 & 0x7fffffff | (r1 & 0x1) << 31

  # i = 5
  t0 = @xS0[r0 & 0xff] ^
       @xS1[r0 >> 8 & 0xff] ^
       @xS2[r0 >> 16 & 0xff] ^
       @xS3[r0 >> 24 & 0xff]
  t1 = @xS0[r1 >> 24 & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[r1 >> 8 & 0xff] ^
       @xS3[r1 >> 16 & 0xff]

  r2 = r2 >> 31 & 0x1 | (r2 & 0x7fffffff) << 1
  r2 ^= 0xffffffff & (t0 + t1 + @k[30])

  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[31])
  r3 = r3 >> 1 & 0x7fffffff | (r3 & 0x1) << 31

  t0 = @xS0[r2 & 0xff] ^
       @xS1[r2 >> 8 & 0xff] ^
       @xS2[r2 >> 16 & 0xff] ^
       @xS3[r2 >> 24 & 0xff]
  t1 = @xS0[r3 >> 24 & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[r3 >> 8 & 0xff] ^
       @xS3[r3 >> 16 & 0xff]

  r0 = r0 >> 31 & 0x1 | (r0 & 0x7fffffff) << 1
  r0 ^= 0xffffffff & (t0 + t1 + @k[28])

  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[29])
  r1 = r1 >> 1 & 0x7fffffff | (r1 & 0x1) << 31

  # i = 4
  t0 = @xS0[r0 & 0xff] ^
       @xS1[r0 >> 8 & 0xff] ^
       @xS2[r0 >> 16 & 0xff] ^
       @xS3[r0 >> 24 & 0xff]
  t1 = @xS0[r1 >> 24 & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[r1 >> 8 & 0xff] ^
       @xS3[r1 >> 16 & 0xff]

  r2 = r2 >> 31 & 0x1 | (r2 & 0x7fffffff) << 1
  r2 ^= 0xffffffff & (t0 + t1 + @k[26])

  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[27])
  r3 = r3 >> 1 & 0x7fffffff | (r3 & 0x1) << 31

  t0 = @xS0[r2 & 0xff] ^
       @xS1[r2 >> 8 & 0xff] ^
       @xS2[r2 >> 16 & 0xff] ^
       @xS3[r2 >> 24 & 0xff]
  t1 = @xS0[r3 >> 24 & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[r3 >> 8 & 0xff] ^
       @xS3[r3 >> 16 & 0xff]

  r0 = r0 >> 31 & 0x1 | (r0 & 0x7fffffff) << 1
  r0 ^= 0xffffffff & (t0 + t1 + @k[24])

  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[25])
  r1 = r1 >> 1 & 0x7fffffff | (r1 & 0x1) << 31

  # i = 3
  t0 = @xS0[r0 & 0xff] ^
       @xS1[r0 >> 8 & 0xff] ^
       @xS2[r0 >> 16 & 0xff] ^
       @xS3[r0 >> 24 & 0xff]
  t1 = @xS0[r1 >> 24 & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[r1 >> 8 & 0xff] ^
       @xS3[r1 >> 16 & 0xff]

  r2 = r2 >> 31 & 0x1 | (r2 & 0x7fffffff) << 1
  r2 ^= 0xffffffff & (t0 + t1 + @k[22])

  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[23])
  r3 = r3 >> 1 & 0x7fffffff | (r3 & 0x1) << 31

  t0 = @xS0[r2 & 0xff] ^
       @xS1[r2 >> 8 & 0xff] ^
       @xS2[r2 >> 16 & 0xff] ^
       @xS3[r2 >> 24 & 0xff]
  t1 = @xS0[r3 >> 24 & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[r3 >> 8 & 0xff] ^
       @xS3[r3 >> 16 & 0xff]

  r0 = r0 >> 31 & 0x1 | (r0 & 0x7fffffff) << 1
  r0 ^= 0xffffffff & (t0 + t1 + @k[20])

  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[21])
  r1 = r1 >> 1 & 0x7fffffff | (r1 & 0x1) << 31

  # i = 2
  t0 = @xS0[r0 & 0xff] ^
       @xS1[r0 >> 8 & 0xff] ^
       @xS2[r0 >> 16 & 0xff] ^
       @xS3[r0 >> 24 & 0xff]
  t1 = @xS0[r1 >> 24 & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[r1 >> 8 & 0xff] ^
       @xS3[r1 >> 16 & 0xff]

  r2 = r2 >> 31 & 0x1 | (r2 & 0x7fffffff) << 1
  r2 ^= 0xffffffff & (t0 + t1 + @k[18])

  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[19])
  r3 = r3 >> 1 & 0x7fffffff | (r3 & 0x1) << 31

  t0 = @xS0[r2 & 0xff] ^
       @xS1[r2 >> 8 & 0xff] ^
       @xS2[r2 >> 16 & 0xff] ^
       @xS3[r2 >> 24 & 0xff]
  t1 = @xS0[r3 >> 24 & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[r3 >> 8 & 0xff] ^
       @xS3[r3 >> 16 & 0xff]

  r0 = r0 >> 31 & 0x1 | (r0 & 0x7fffffff) << 1
  r0 ^= 0xffffffff & (t0 + t1 + @k[16])

  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[17])
  r1 = r1 >> 1 & 0x7fffffff | (r1 & 0x1) << 31

  # i = 1
  t0 = @xS0[r0 & 0xff] ^
       @xS1[r0 >> 8 & 0xff] ^
       @xS2[r0 >> 16 & 0xff] ^
       @xS3[r0 >> 24 & 0xff]
  t1 = @xS0[r1 >> 24 & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[r1 >> 8 & 0xff] ^
       @xS3[r1 >> 16 & 0xff]

  r2 = r2 >> 31 & 0x1 | (r2 & 0x7fffffff) << 1
  r2 ^= 0xffffffff & (t0 + t1 + @k[14])

  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[15])
  r3 = r3 >> 1 & 0x7fffffff | (r3 & 0x1) << 31

  t0 = @xS0[r2 & 0xff] ^
       @xS1[r2 >> 8 & 0xff] ^
       @xS2[r2 >> 16 & 0xff] ^
       @xS3[r2 >> 24 & 0xff]
  t1 = @xS0[r3 >> 24 & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[r3 >> 8 & 0xff] ^
       @xS3[r3 >> 16 & 0xff]

  r0 = r0 >> 31 & 0x1 | (r0 & 0x7fffffff) << 1
  r0 ^= 0xffffffff & (t0 + t1 + @k[12])

  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[13])
  r1 = r1 >> 1 & 0x7fffffff | (r1 & 0x1) << 31

  # i = 0
  t0 = @xS0[r0 & 0xff] ^
       @xS1[r0 >> 8 & 0xff] ^
       @xS2[r0 >> 16 & 0xff] ^
       @xS3[r0 >> 24 & 0xff]
  t1 = @xS0[r1 >> 24 & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[r1 >> 8 & 0xff] ^
       @xS3[r1 >> 16 & 0xff]

  r2 = r2 >> 31 & 0x1 | (r2 & 0x7fffffff) << 1
  r2 ^= 0xffffffff & (t0 + t1 + @k[10])

  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[11])
  r3 = r3 >> 1 & 0x7fffffff | (r3 & 0x1) << 31

  t0 = @xS0[r2 & 0xff] ^
       @xS1[r2 >> 8 & 0xff] ^
       @xS2[r2 >> 16 & 0xff] ^
       @xS3[r2 >> 24 & 0xff]
  t1 = @xS0[r3 >> 24 & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[r3 >> 8 & 0xff] ^
       @xS3[r3 >> 16 & 0xff]

  r0 = r0 >> 31 & 0x1 | (r0 & 0x7fffffff) << 1
  r0 ^= 0xffffffff & (t0 + t1 + @k[8])

  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[9])
  r1 = r1 >> 1 & 0x7fffffff | (r1 & 0x1) << 31

  [@k[0] ^ r2, @k[1] ^ r3, @k[2] ^ r0, @k[3] ^ r1].pack("V4")
end

#encrypt(plaintext) ⇒ `Object`

Encrypt a plaintext string, chunking as required for CBC mode.

# File 'lib/twofish.rb', line 473

def encrypt(plaintext)
  plaintext = plaintext.dup.force_encoding('ASCII-8BIT')
  padded_plaintext = Padding.pad!(plaintext, BLOCK_SIZE, @padding)
  result = ''.force_encoding('ASCII-8BIT')
  if @mode == Mode::CBC
    @iv ||= SecureRandom.random_bytes(BLOCK_SIZE)
    @_feedback ||= @iv
  end
  (0...padded_plaintext.length).step(BLOCK_SIZE) do |block_ptr|
    plaintext_block = padded_plaintext[block_ptr, BLOCK_SIZE]
    xor_block!(plaintext_block, @_feedback) if Mode::CBC == @mode
    result << @_feedback = encrypt_block(plaintext_block)
  end
  result
end

#encrypt_block(plain_text) ⇒ `Object`

Encrypt a single block (16 bytes).

# File 'lib/twofish.rb', line 526

def encrypt_block(plain_text)

  words = plain_text.unpack('V4')

  r0 = @k[0] ^ words[0]
  r1 = @k[1] ^ words[1]
  r2 = @k[2] ^ words[2]
  r3 = @k[3] ^ words[3]

  # i = 0
  t0 = @xS0[r0 & 0xff] ^
       @xS1[(r0 >> 8) & 0xff] ^
       @xS2[(r0 >> 16) & 0xff] ^
       @xS3[(r0 >> 24) & 0xff]
  t1 = @xS0[(r1 >> 24) & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[(r1 >> 8) & 0xff] ^
       @xS3[(r1 >> 16) & 0xff]

  r2 ^= 0xffffffff & (t0 + t1 + @k[8])
  r2 = (r2 >> 1 & 0x7fffffff) | (r2 & 0x1) << 31

  r3 = ((r3 >> 31) & 1) | (r3 & 0x7fffffff) << 1
  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[9])

  t0 = @xS0[r2 & 0xff] ^
       @xS1[(r2 >> 8) & 0xff] ^
       @xS2[(r2 >> 16) & 0xff] ^
       @xS3[(r2 >> 24) & 0xff]
  t1 = @xS0[(r3 >> 24) & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[(r3 >> 8) & 0xff] ^
       @xS3[(r3 >> 16) & 0xff]

  r0 ^= 0xffffffff & (t0 + t1 + @k[10])
  r0 = (r0 >> 1 & 0x7fffffff) | (r0 & 0x1) << 31

  r1 = ((r1 >> 31) & 1) | (r1 & 0x7fffffff) << 1
  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[11])

  # i = 1
  t0 = @xS0[r0 & 0xff] ^
       @xS1[(r0 >> 8) & 0xff] ^
       @xS2[(r0 >> 16) & 0xff] ^
       @xS3[(r0 >> 24) & 0xff]
  t1 = @xS0[(r1 >> 24) & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[(r1 >> 8) & 0xff] ^
       @xS3[(r1 >> 16) & 0xff]

  r2 ^= 0xffffffff & (t0 + t1 + @k[12])
  r2 = (r2 >> 1 & 0x7fffffff) | (r2 & 0x1) << 31

  r3 = ((r3 >> 31) & 1) | (r3 & 0x7fffffff) << 1
  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[13])

  t0 = @xS0[r2 & 0xff] ^
       @xS1[(r2 >> 8) & 0xff] ^
       @xS2[(r2 >> 16) & 0xff] ^
       @xS3[(r2 >> 24) & 0xff]
  t1 = @xS0[(r3 >> 24) & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[(r3 >> 8) & 0xff] ^
       @xS3[(r3 >> 16) & 0xff]

  r0 ^= 0xffffffff & (t0 + t1 + @k[14])
  r0 = (r0 >> 1 & 0x7fffffff) | (r0 & 0x1) << 31

  r1 = ((r1 >> 31) & 1) | (r1 & 0x7fffffff) << 1
  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[15])

  # i = 2
  t0 = @xS0[r0 & 0xff] ^
       @xS1[(r0 >> 8) & 0xff] ^
       @xS2[(r0 >> 16) & 0xff] ^
       @xS3[(r0 >> 24) & 0xff]
  t1 = @xS0[(r1 >> 24) & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[(r1 >> 8) & 0xff] ^
       @xS3[(r1 >> 16) & 0xff]

  r2 ^= 0xffffffff & (t0 + t1 + @k[16])
  r2 = (r2 >> 1 & 0x7fffffff) | (r2 & 0x1) << 31

  r3 = ((r3 >> 31) & 1) | (r3 & 0x7fffffff) << 1
  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[17])

  t0 = @xS0[r2 & 0xff] ^
       @xS1[(r2 >> 8) & 0xff] ^
       @xS2[(r2 >> 16) & 0xff] ^
       @xS3[(r2 >> 24) & 0xff]
  t1 = @xS0[(r3 >> 24) & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[(r3 >> 8) & 0xff] ^
       @xS3[(r3 >> 16) & 0xff]

  r0 ^= 0xffffffff & (t0 + t1 + @k[18])
  r0 = (r0 >> 1 & 0x7fffffff) | (r0 & 0x1) << 31

  r1 = ((r1 >> 31) & 1) | (r1 & 0x7fffffff) << 1
  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[19])

  # i = 3
  t0 = @xS0[r0 & 0xff] ^
       @xS1[(r0 >> 8) & 0xff] ^
       @xS2[(r0 >> 16) & 0xff] ^
       @xS3[(r0 >> 24) & 0xff]
  t1 = @xS0[(r1 >> 24) & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[(r1 >> 8) & 0xff] ^
       @xS3[(r1 >> 16) & 0xff]

  r2 ^= 0xffffffff & (t0 + t1 + @k[20])
  r2 = (r2 >> 1 & 0x7fffffff) | (r2 & 0x1) << 31

  r3 = ((r3 >> 31) & 1) | ((r3 & 0x7fffffff) << 1)
  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[21])

  t0 = @xS0[r2 & 0xff] ^
       @xS1[(r2 >> 8) & 0xff] ^
       @xS2[(r2 >> 16) & 0xff] ^
       @xS3[(r2 >> 24) & 0xff]
  t1 = @xS0[(r3 >> 24) & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[(r3 >> 8) & 0xff] ^
       @xS3[(r3 >> 16) & 0xff]

  r0 ^= 0xffffffff & (t0 + t1 + @k[22])
  r0 = (r0 >> 1 & 0x7fffffff) | (r0 & 0x1) << 31

  r1 = ((r1 >> 31) & 1) | (r1 & 0x7fffffff) << 1
  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[23])

  # i = 4
  t0 = @xS0[r0 & 0xff] ^
       @xS1[(r0 >> 8) & 0xff] ^
       @xS2[(r0 >> 16) & 0xff] ^
       @xS3[(r0 >> 24) & 0xff]
  t1 = @xS0[(r1 >> 24) & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[(r1 >> 8) & 0xff] ^
       @xS3[(r1 >> 16) & 0xff]

  r2 ^= 0xffffffff & (t0 + t1 + @k[24])
  r2 = (r2 >> 1 & 0x7fffffff) | (r2 & 0x1) << 31

  r3 = ((r3 >> 31) & 1) | (r3 & 0x7fffffff) << 1
  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[25])

  t0 = @xS0[r2 & 0xff] ^
       @xS1[(r2 >> 8) & 0xff] ^
       @xS2[(r2 >> 16) & 0xff] ^
       @xS3[(r2 >> 24) & 0xff]
  t1 = @xS0[(r3 >> 24) & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[(r3 >> 8) & 0xff] ^
       @xS3[(r3 >> 16) & 0xff]

  r0 ^= 0xffffffff & (t0 + t1 + @k[26])
  r0 = (r0 >> 1 & 0x7fffffff) | (r0 & 0x1) << 31

  r1 = ((r1 >> 31) & 1) | ((r1 & 0x7fffffff) << 1)
  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[27])

  # i = 5
  t0 = @xS0[r0 & 0xff] ^
       @xS1[(r0 >> 8) & 0xff] ^
       @xS2[(r0 >> 16) & 0xff] ^
       @xS3[(r0 >> 24) & 0xff]
  t1 = @xS0[(r1 >> 24) & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[(r1 >> 8) & 0xff] ^
       @xS3[(r1 >> 16) & 0xff]

  r2 ^= 0xffffffff & (t0 + t1 + @k[28])
  r2 = (r2 >> 1 & 0x7fffffff) | (r2 & 0x1) << 31

  r3 = ((r3 >> 31) & 1) | (r3 & 0x7fffffff) << 1
  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[29])

  t0 = @xS0[r2 & 0xff] ^
       @xS1[(r2 >> 8) & 0xff] ^
       @xS2[(r2 >> 16) & 0xff] ^
       @xS3[(r2 >> 24) & 0xff]
  t1 = @xS0[(r3 >> 24) & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[(r3 >> 8) & 0xff] ^
       @xS3[(r3 >> 16) & 0xff]

  r0 ^= 0xffffffff & (t0 + t1 + @k[30])
  r0 = (r0 >> 1 & 0x7fffffff) | (r0 & 0x1) << 31

  r1 = ((r1 >> 31) & 1) | (r1 & 0x7fffffff) << 1
  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[31])

  # i = 6
  t0 = @xS0[r0 & 0xff] ^
       @xS1[(r0 >> 8) & 0xff] ^
       @xS2[(r0 >> 16) & 0xff] ^
       @xS3[(r0 >> 24) & 0xff]
  t1 = @xS0[(r1 >> 24) & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[(r1 >> 8) & 0xff] ^
       @xS3[(r1 >> 16) & 0xff]

  r2 ^= 0xffffffff & (t0 + t1 + @k[32])
  r2 = (r2 >> 1 & 0x7fffffff) | (r2 & 0x1) << 31

  r3 = ((r3 >> 31) & 1) | (r3 & 0x7fffffff) << 1
  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[33])

  t0 = @xS0[r2 & 0xff] ^
       @xS1[(r2 >> 8) & 0xff] ^
       @xS2[(r2 >> 16) & 0xff] ^
       @xS3[(r2 >> 24) & 0xff]
  t1 = @xS0[(r3 >> 24) & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[(r3 >> 8) & 0xff] ^
       @xS3[(r3 >> 16) & 0xff]

  r0 ^= 0xffffffff & (t0 + t1 + @k[34])
  r0 = (r0 >> 1 & 0x7fffffff) | (r0 & 0x1) << 31

  r1 = ((r1 >> 31) & 1) | (r1 & 0x7fffffff) << 1
  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[35])

  # i = 7
  t0 = @xS0[r0 & 0xff] ^
       @xS1[(r0 >> 8) & 0xff] ^
       @xS2[(r0 >> 16) & 0xff] ^
       @xS3[(r0 >> 24) & 0xff]
  t1 = @xS0[(r1 >> 24) & 0xff] ^
       @xS1[r1 & 0xff] ^
       @xS2[(r1 >> 8) & 0xff] ^
       @xS3[(r1 >> 16) & 0xff]

  r2 ^= 0xffffffff & (t0 + t1 + @k[36])
  r2 = (r2 >> 1 & 0x7fffffff) | (r2 & 0x1) << 31

  r3 = ((r3 >> 31) & 1) | (r3 & 0x7fffffff) << 1
  r3 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[37])

  t0 = @xS0[r2 & 0xff] ^
       @xS1[(r2 >> 8) & 0xff] ^
       @xS2[(r2 >> 16) & 0xff] ^
       @xS3[(r2 >> 24) & 0xff]
  t1 = @xS0[(r3 >> 24) & 0xff] ^
       @xS1[r3 & 0xff] ^
       @xS2[(r3 >> 8) & 0xff] ^
       @xS3[(r3 >> 16) & 0xff]

  r0 ^= 0xffffffff & (t0 + t1 + @k[38])
  r0 = (r0 >> 1 & 0x7fffffff) | (r0 & 0x1) << 31

  r1 = ((r1 >> 31) & 1) | (r1 & 0x7fffffff) << 1
  r1 ^= 0xffffffff & (t0 + ((t1 & 0x7fffffff) << 1) + @k[39])

  [@k[4] ^ r2, @k[5] ^ r3, @k[6] ^ r0, @k[7] ^ r1].pack("V4")
end

#reset! ⇒ `Object`

Reset the cipher state (for feedback modes).



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# File 'lib/twofish.rb', line 515

def reset!
  @_feedback = nil
end

#xor_block!(target, source) ⇒ `Object`

Exclusive-or two blocks together, byte-by-byte, storing the result in the first block.



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# File 'lib/twofish.rb', line 521

def xor_block!(target, source)
  (0...BLOCK_SIZE).each { |i| target[i] = (target[i].ord ^ source[i].ord).chr }
end

Class: Twofish

Overview

Defined Under Namespace

Constant Summary collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(key_string, opts = {}) ⇒ Twofish

Instance Attribute Details

#iv ⇒ Object

#key_size ⇒ Object (readonly)

#mode ⇒ Object

#padding ⇒ Object

Class Method Details

.block_size ⇒ Object

Instance Method Details

#decrypt(ciphertext) ⇒ Object

#decrypt_block(plain) ⇒ Object

#encrypt(plaintext) ⇒ Object

#encrypt_block(plain_text) ⇒ Object

#reset! ⇒ Object

#xor_block!(target, source) ⇒ Object