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Cantor–Zassenhaus algorithm

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1078: 3124:, which involves the factorisation of field elements. If we represent the prime-power order field in the usual way – that is, as polynomials over the prime order base field, reduced modulo an irreducible polynomial of appropriate degree – then this is simply polynomial factorisation, as provided by the Cantor–Zassenhaus algorithm. 809: 1252: 2573: 698: 3266: 1506: 477: 1073:{\displaystyle {\begin{aligned}g(x)&{}\equiv g_{1}(x){\pmod {p_{1}(x)}},\\g(x)&{}\equiv g_{2}(x){\pmod {p_{2}(x)}},\\&{}\ \ \vdots \\g(x)&{}\equiv g_{s}(x){\pmod {p_{s}(x)}},\end{aligned}}} 2146: 2043: 1940: 1086: 814: 592: 2640: 2408: 3267:
https://web.archive.org/web/20200301213349/http://blog.fkraiem.org/2013/12/01/polynomial-factorisation-over-finite-fields-part-3-final-splitting-cantor-zassenhaus-in-odd-characteristic/
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factors are all of equal degree (algorithms exist for efficiently factoring arbitrary polynomials into a product of polynomials satisfying these conditions, for instance,
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is of odd-characteristic (the process can be generalised to characteristic 2 fields in a fairly straightforward way. Select a random polynomial
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are non-empty and by computing the above GCDs we may obtain non-trivial factors. Since the ring of polynomials over a field is a
1254:. It is important to note the following at this point, as it shall be of critical importance later in the algorithm: Since the 2051: 1948: 1851: 1247:{\displaystyle \phi (g(x)+\langle f(x)\rangle )=(g_{1}(x)+\langle p_{1}(x)\rangle ,\ldots ,g_{s}(x)+\langle p_{s}(x)\rangle )} 3137: 250:, so that the Cantor–Zassenhaus algorithm can be used to factor arbitrary polynomials). It gives as output a polynomial 511: 2581: 2568:{\displaystyle \phi (b(x)^{m})=(b_{1}^{m}(x)+\langle p_{1}(x)\rangle ,\ldots ,b_{s}^{m}(x)+\langle p_{s}(x)\rangle ).} 2185:
above using the isomorphism discussed in the Background section. It proceeds as follows, in the case where the field
371: 337:. The algorithm may then be applied recursively to these and subsequent divisors, until we find the decomposition of 1290:
are each irreducible, each of the factor rings in this direct sum is in fact a field. These fields each have degree
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Elia, Michele; Schipani, Davide (2015), "Improvements on the Cantor–Zassenhaus factorization algorithm",
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over finite fields of prime-power order. Computing discrete logarithms is an important problem in
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It is arguably the dominant algorithm for solving the problem, having replaced the earlier
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The core result underlying the Cantor–Zassenhaus algorithm is the following: If
407: 3181:(April 1981), "A new algorithm for factoring polynomials over finite fields", 31: 3112:
One important application of the Cantor–Zassenhaus algorithm is in computing
3250: 2669:, as noted earlier. The multiplicative subgroup of this field has order 2156:
The Cantor–Zassenhaus algorithm computes polynomials of the same type as
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as before, and if any two of the following three sets is non-empty:
1501:{\displaystyle a_{i}(x)\in \{0,-1,1\}{\text{ for }}i=1,2,\ldots ,s,} 3235:(3), Institute of Mathematics, Czech Academy of Sciences: 271–290, 3241: 472:{\displaystyle R={\frac {\mathbb {F} _{q}}{\langle f(x)\rangle }}} 2402:
is an isomorphism, we have (using our now-established notation):
41:
The algorithm consists mainly of exponentiation and polynomial
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into powers of irreducible polynomials (recalling that the
2141:{\displaystyle \gcd(f(x),a(x)-1)=\prod _{i\in C}p_{i}(x).} 2038:{\displaystyle \gcd(f(x),a(x)+1)=\prod _{i\in B}p_{i}(x),} 1935:{\displaystyle \gcd(f(x),a(x))=\prod _{i\in A}p_{i}(x),} 3132:
The Cantor–Zassenhaus algorithm is implemented in the
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then there exist the following non-trivial factors of
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Algorithm for factoring polynomials over finite fields
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is a squarefree polynomial with the same factors as
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It is currently implemented in many 8: 2629: 2607: 2556: 2534: 2495: 2473: 1797: 1763: 1731: 1694: 1662: 1628: 1460: 1439: 1238: 1216: 1182: 1160: 1126: 1111: 767:-tuple of its reductions modulo each of the 684: 662: 463: 448: 3128:Implementation in computer algebra systems 3240: 3196: 3071: 3027: 2998: 2977: 2962: 2935: 2919: 2913: 2877: 2871: 2837: 2821: 2815: 2776: 2771: 2755: 2749: 2713: 2707: 2680: 2674: 2653: 2647: 2614: 2589: 2583: 2541: 2516: 2511: 2480: 2455: 2450: 2431: 2410: 2387: 2366: 2351: 2328: 2313: 2298: 2254: 2219: 2198: 2194: 2193: 2190: 2161: 2120: 2104: 2053: 2017: 2001: 1950: 1914: 1898: 1853: 1821: 1776: 1755: 1707: 1686: 1641: 1620: 1587: 1581: 1552: 1522: 1516: 1463: 1421: 1415: 1368: 1330: 1301: 1295: 1265: 1259: 1223: 1198: 1167: 1142: 1088: 1044: 1031: 1016: 1007: 976: 949: 936: 921: 912: 870: 857: 842: 833: 813: 811: 778: 772: 733: 713: 669: 645: 641: 640: 636: 630: 619: 607: 569: 541: 519: 513: 484: 431: 427: 426: 422: 414: 382: 342: 313: 284: 255: 226: 165: 151: 126: 122: 121: 118: 85: 1740:{\displaystyle B=\{i\mid a_{i}(x)=-1\},} 3166: 1806:{\displaystyle C=\{i\mid a_{i}(x)=1\},} 1671:{\displaystyle A=\{i\mid a_{i}(x)=0\},} 3100:, we may compute these GCDs using the 214:{\displaystyle f(x)/\gcd(f(x),f'(x))} 7: 2993:is a polynomial of the same type as 2799:{\displaystyle b_{i}(x)^{q^{d}-1}=1} 113:with coefficients in a finite field 3292:Polynomial factorization algorithms 1039: 944: 865: 370:of polynomials over any field is a 2855:{\displaystyle b_{i}(x)^{m}=\pm 1} 2642:is an element of a field of order 14: 3198:10.1090/S0025-5718-1981-0606517-5 45:computations. It was invented by 3059:{\displaystyle b(x)\neq 0,\pm 1} 2286:{\displaystyle b(x)\neq 0,\pm 1} 2207:{\displaystyle \mathbb {F} _{q}} 1400:{\displaystyle a(x)\neq 0,\pm 1} 135:{\displaystyle \mathbb {F} _{q}} 3136:computer algebra system as the 1032: 937: 858: 3038: 3032: 3009: 3003: 2974: 2967: 2950:{\displaystyle b_{i}(x)^{m}=0} 2932: 2925: 2889: 2883: 2834: 2827: 2768: 2761: 2725: 2719: 2626: 2620: 2601: 2595: 2559: 2553: 2547: 2528: 2522: 2492: 2486: 2467: 2461: 2443: 2437: 2428: 2421: 2415: 2363: 2356: 2325: 2306: 2265: 2259: 2230: 2224: 2172: 2166: 2132: 2126: 2094: 2085: 2079: 2070: 2064: 2058: 2029: 2023: 1991: 1982: 1976: 1967: 1961: 1955: 1926: 1920: 1888: 1885: 1879: 1870: 1864: 1858: 1832: 1826: 1788: 1782: 1719: 1713: 1653: 1647: 1599: 1593: 1563: 1557: 1534: 1528: 1433: 1427: 1379: 1373: 1341: 1335: 1277: 1271: 1241: 1235: 1229: 1210: 1204: 1179: 1173: 1154: 1148: 1135: 1129: 1123: 1117: 1105: 1099: 1093: 1059: 1056: 1050: 1033: 1028: 1022: 1000: 994: 964: 961: 955: 938: 933: 927: 905: 899: 885: 882: 876: 859: 854: 848: 826: 820: 790: 784: 744: 738: 681: 675: 657: 651: 581: 575: 553: 547: 531: 525: 495: 489: 460: 454: 443: 437: 393: 387: 353: 347: 324: 318: 295: 289: 266: 260: 237: 231: 208: 205: 199: 185: 179: 173: 162: 156: 96: 90: 1: 2339:{\displaystyle m=(q^{d}-1)/2} 38:(also called Galois fields). 1360:is a polynomial satisfying: 3066:, at least two of the sets 372:unique factorisation domain 28:Cantor–Zassenhaus algorithm 3308: 3184:Mathematics of Computation 2901:{\displaystyle b_{i}(x)=0} 2737:{\displaystyle b_{i}(x)=0} 30:is a method for factoring 2242:{\displaystyle b(x)\in R} 1353:{\displaystyle a(x)\in R} 756:{\displaystyle g(x)\in R} 406:are contained within the 3150:Polynomial factorization 2986:{\displaystyle b(x)^{m}} 2375:{\displaystyle b(x)^{m}} 1605:{\displaystyle p_{i}(x)} 1540:{\displaystyle a_{i}(x)} 1283:{\displaystyle p_{i}(x)} 796:{\displaystyle p_{i}(x)} 700:. The isomorphism from 508:has irreducible factors 377:All possible factors of 62:computer algebra systems 3251:10.21136/mb.2015.144395 3118:public key cryptography 3022:above. Further, since 2695:{\displaystyle q^{d}-1} 3086: 3060: 3016: 2987: 2951: 2902: 2856: 2800: 2738: 2696: 2663: 2636: 2569: 2396: 2376: 2340: 2287: 2243: 2208: 2179: 2142: 2039: 1936: 1839: 1807: 1741: 1672: 1606: 1570: 1541: 1502: 1401: 1354: 1311: 1284: 1248: 1074: 797: 757: 722: 694: 635: 588: 502: 479:. If we suppose that 473: 400: 360: 331: 302: 273: 244: 215: 144:irreducible polynomial 136: 103: 79:square-free polynomial 3122:index calculus method 3087: 3061: 3017: 2988: 2952: 2903: 2857: 2801: 2739: 2697: 2664: 2662:{\displaystyle q^{d}} 2637: 2570: 2397: 2395:{\displaystyle \phi } 2377: 2341: 2288: 2244: 2209: 2180: 2143: 2040: 1937: 1840: 1808: 1742: 1673: 1607: 1571: 1542: 1503: 1402: 1355: 1312: 1310:{\displaystyle q^{d}} 1285: 1249: 1075: 798: 758: 723: 721:{\displaystyle \phi } 695: 615: 589: 503: 474: 401: 361: 332: 303: 274: 245: 216: 137: 104: 58:Berlekamp's algorithm 3229:Mathematica Bohemica 3070: 3026: 3015:{\displaystyle a(x)} 2997: 2961: 2912: 2870: 2814: 2748: 2706: 2673: 2646: 2582: 2409: 2386: 2350: 2297: 2253: 2218: 2189: 2178:{\displaystyle a(x)} 2160: 2052: 1949: 1852: 1838:{\displaystyle f(x)} 1820: 1754: 1685: 1619: 1580: 1569:{\displaystyle a(x)} 1551: 1547:is the reduction of 1515: 1414: 1367: 1329: 1294: 1258: 1087: 810: 771: 732: 728:, maps a polynomial 712: 606: 512: 501:{\displaystyle f(x)} 483: 413: 399:{\displaystyle f(x)} 381: 359:{\displaystyle f(x)} 341: 330:{\displaystyle f(x)} 312: 301:{\displaystyle g(x)} 283: 272:{\displaystyle g(x)} 254: 243:{\displaystyle f(x)} 225: 150: 117: 102:{\displaystyle f(x)} 84: 3114:discrete logarithms 3102:Euclidean algorithm 3085:{\displaystyle A,B} 2521: 2460: 3082: 3056: 3012: 2983: 2947: 2898: 2852: 2796: 2734: 2692: 2659: 2632: 2565: 2507: 2446: 2392: 2372: 2336: 2283: 2239: 2204: 2175: 2138: 2115: 2035: 2012: 1932: 1909: 1835: 1803: 1737: 1668: 1602: 1566: 1537: 1498: 1397: 1350: 1307: 1280: 1244: 1070: 1068: 793: 753: 718: 690: 584: 498: 469: 396: 356: 327: 298: 269: 240: 211: 132: 99: 2908:, then of course 2100: 1997: 1894: 1466: 983: 980: 688: 467: 3299: 3282:Computer algebra 3254: 3253: 3244: 3224: 3218: 3217: 3200: 3191:(154): 587–592, 3179:Zassenhaus, Hans 3175:Cantor, David G. 3171: 3098:Euclidean domain 3091: 3089: 3088: 3083: 3065: 3063: 3062: 3057: 3021: 3019: 3018: 3013: 2992: 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339: 338: 310: 309: 281: 280: 252: 251: 223: 222: 191: 148: 147: 120: 115: 114: 82: 81: 75: 70: 51:Hans Zassenhaus 47:David G. Cantor 17: 12: 11: 5: 3305: 3303: 3295: 3294: 3289: 3284: 3274: 3273: 3270: 3269: 3262: 3261:External links 3259: 3256: 3255: 3219: 3165: 3164: 3162: 3159: 3158: 3157: 3152: 3145: 3142: 3138:factorcantor() 3129: 3126: 3109: 3106: 3081: 3078: 3075: 3055: 3052: 3049: 3046: 3043: 3040: 3037: 3034: 3031: 3011: 3008: 3005: 3002: 2980: 2976: 2972: 2969: 2966: 2946: 2943: 2938: 2934: 2930: 2927: 2922: 2918: 2897: 2894: 2891: 2888: 2885: 2880: 2876: 2851: 2848: 2845: 2840: 2836: 2832: 2829: 2824: 2820: 2795: 2792: 2787: 2784: 2779: 2775: 2770: 2766: 2763: 2758: 2754: 2733: 2730: 2727: 2724: 2721: 2716: 2712: 2691: 2688: 2683: 2679: 2656: 2652: 2631: 2628: 2625: 2622: 2617: 2613: 2609: 2606: 2603: 2600: 2597: 2592: 2588: 2576: 2575: 2564: 2561: 2558: 2555: 2552: 2549: 2544: 2540: 2536: 2533: 2530: 2527: 2524: 2519: 2514: 2510: 2506: 2503: 2500: 2497: 2494: 2491: 2488: 2483: 2479: 2475: 2472: 2469: 2466: 2463: 2458: 2453: 2449: 2445: 2442: 2439: 2434: 2430: 2426: 2423: 2420: 2417: 2414: 2391: 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1633: 1630: 1627: 1624: 1601: 1598: 1595: 1590: 1586: 1565: 1562: 1559: 1556: 1536: 1533: 1530: 1525: 1521: 1509: 1508: 1497: 1494: 1491: 1488: 1485: 1482: 1479: 1476: 1473: 1470: 1462: 1459: 1456: 1453: 1450: 1447: 1444: 1441: 1438: 1435: 1432: 1429: 1424: 1420: 1408: 1407: 1396: 1393: 1390: 1387: 1384: 1381: 1378: 1375: 1372: 1349: 1346: 1343: 1340: 1337: 1334: 1322: 1319: 1304: 1300: 1279: 1276: 1273: 1268: 1264: 1243: 1240: 1237: 1234: 1231: 1226: 1222: 1218: 1215: 1212: 1209: 1206: 1201: 1197: 1193: 1190: 1187: 1184: 1181: 1178: 1175: 1170: 1166: 1162: 1159: 1156: 1153: 1150: 1145: 1141: 1137: 1134: 1131: 1128: 1125: 1122: 1119: 1116: 1113: 1110: 1107: 1104: 1101: 1098: 1095: 1092: 1081: 1080: 1065: 1061: 1058: 1055: 1052: 1047: 1043: 1038: 1035: 1030: 1027: 1024: 1019: 1015: 1011: 1006: 1004: 1002: 999: 996: 993: 990: 989: 986: 975: 973: 970: 966: 963: 960: 957: 952: 948: 943: 940: 935: 932: 929: 924: 920: 916: 911: 909: 907: 904: 901: 898: 895: 894: 891: 887: 884: 881: 878: 873: 869: 864: 861: 856: 853: 850: 845: 841: 837: 832: 830: 828: 825: 822: 819: 816: 815: 792: 789: 786: 781: 777: 752: 749: 746: 743: 740: 737: 717: 686: 683: 680: 677: 672: 668: 664: 659: 656: 653: 648: 643: 633: 628: 625: 622: 618: 614: 611: 600:direct product 583: 580: 577: 572: 568: 564: 561: 558: 555: 552: 549: 544: 540: 536: 533: 530: 527: 522: 518: 497: 494: 491: 488: 465: 462: 459: 456: 453: 450: 445: 442: 439: 434: 429: 421: 418: 395: 392: 389: 386: 355: 352: 349: 346: 326: 323: 320: 317: 297: 294: 291: 288: 268: 265: 262: 259: 239: 236: 233: 230: 210: 207: 204: 201: 197: 194: 190: 187: 184: 181: 178: 175: 172: 168: 164: 161: 158: 155: 129: 124: 98: 95: 92: 89: 74: 71: 69: 66: 15: 13: 10: 9: 6: 4: 3: 2: 3304: 3293: 3290: 3288: 3287:Finite fields 3285: 3283: 3280: 3279: 3277: 3268: 3265: 3264: 3260: 3252: 3248: 3243: 3238: 3234: 3230: 3223: 3220: 3216: 3212: 3208: 3204: 3199: 3194: 3190: 3186: 3185: 3180: 3176: 3170: 3167: 3160: 3156: 3153: 3151: 3148: 3147: 3143: 3141: 3139: 3135: 3127: 3125: 3123: 3119: 3115: 3107: 3105: 3103: 3099: 3095: 3079: 3076: 3073: 3053: 3050: 3047: 3044: 3041: 3035: 3029: 3006: 3000: 2978: 2970: 2964: 2944: 2941: 2936: 2928: 2920: 2916: 2895: 2892: 2886: 2878: 2874: 2865: 2849: 2846: 2843: 2838: 2830: 2822: 2818: 2809: 2793: 2790: 2785: 2782: 2777: 2773: 2764: 2756: 2752: 2731: 2728: 2722: 2714: 2710: 2689: 2686: 2681: 2677: 2654: 2650: 2623: 2615: 2611: 2604: 2598: 2590: 2586: 2562: 2550: 2542: 2538: 2531: 2525: 2517: 2512: 2508: 2504: 2501: 2498: 2489: 2481: 2477: 2470: 2464: 2456: 2451: 2447: 2440: 2432: 2424: 2418: 2412: 2405: 2404: 2403: 2389: 2367: 2359: 2353: 2333: 2329: 2322: 2319: 2314: 2310: 2303: 2300: 2280: 2277: 2274: 2271: 2268: 2262: 2256: 2236: 2233: 2227: 2221: 2199: 2169: 2163: 2151: 2135: 2129: 2121: 2117: 2111: 2108: 2105: 2101: 2097: 2091: 2088: 2082: 2076: 2073: 2067: 2061: 2048: 2047: 2032: 2026: 2018: 2014: 2008: 2005: 2002: 1998: 1994: 1988: 1985: 1979: 1973: 1970: 1964: 1958: 1945: 1944: 1929: 1923: 1915: 1911: 1905: 1902: 1899: 1895: 1891: 1882: 1876: 1873: 1867: 1861: 1848: 1847: 1846: 1829: 1823: 1800: 1794: 1791: 1785: 1777: 1773: 1769: 1766: 1760: 1757: 1750: 1749: 1734: 1728: 1725: 1722: 1716: 1708: 1704: 1700: 1697: 1691: 1688: 1681: 1680: 1665: 1659: 1656: 1650: 1642: 1638: 1634: 1631: 1625: 1622: 1615: 1614: 1613: 1596: 1588: 1584: 1560: 1554: 1531: 1523: 1519: 1495: 1492: 1489: 1486: 1483: 1480: 1477: 1474: 1471: 1468: 1457: 1454: 1451: 1448: 1445: 1442: 1436: 1430: 1422: 1418: 1410: 1409: 1394: 1391: 1388: 1385: 1382: 1376: 1370: 1363: 1362: 1361: 1347: 1344: 1338: 1332: 1320: 1318: 1302: 1298: 1274: 1266: 1262: 1232: 1224: 1220: 1213: 1207: 1199: 1195: 1191: 1188: 1185: 1176: 1168: 1164: 1157: 1151: 1143: 1139: 1132: 1120: 1114: 1108: 1102: 1096: 1090: 1063: 1053: 1045: 1041: 1036: 1025: 1017: 1013: 1009: 1005: 997: 991: 984: 968: 958: 950: 946: 941: 930: 922: 918: 914: 910: 902: 896: 889: 879: 871: 867: 862: 851: 843: 839: 835: 831: 823: 817: 806: 805: 804: 787: 779: 775: 766: 750: 747: 741: 735: 715: 707: 703: 678: 670: 666: 654: 646: 631: 626: 623: 620: 616: 612: 609: 601: 597: 578: 570: 566: 562: 559: 556: 550: 542: 538: 534: 528: 520: 516: 492: 486: 457: 451: 440: 432: 419: 416: 409: 390: 384: 375: 373: 369: 350: 344: 321: 315: 292: 286: 263: 257: 234: 228: 202: 195: 192: 188: 182: 176: 166: 159: 153: 145: 127: 112: 93: 87: 80: 72: 67: 65: 63: 59: 54: 52: 48: 44: 39: 37: 36:finite fields 33: 29: 25: 22: 21:computational 3232: 3228: 3222: 3188: 3182: 3169: 3131: 3111: 3108:Applications 3093: 2863: 2807: 2577: 2346:and compute 2155: 1815: 1510: 1324: 1082: 764: 705: 701: 595: 376: 110: 76: 55: 40: 27: 18: 1321:Core result 803:, i.e. if: 408:factor ring 32:polynomials 3276:Categories 3161:References 3140:function. 2810:and hence 2744:, we have 2578:Now, each 2249:such that 73:Background 3242:1012.5322 3051:± 3042:≠ 2957:. Hence 2862:for each 2847:± 2806:for each 2783:− 2687:− 2630:⟩ 2608:⟨ 2557:⟩ 2535:⟨ 2502:… 2496:⟩ 2474:⟨ 2413:ϕ 2390:ϕ 2382:. Since 2320:− 2278:± 2269:≠ 2234:∈ 2152:Algorithm 2109:∈ 2102:∏ 2089:− 2006:∈ 1999:∏ 1903:∈ 1896:∏ 1770:∣ 1726:− 1701:∣ 1635:∣ 1487:… 1449:− 1437:∈ 1392:± 1383:≠ 1345:∈ 1239:⟩ 1217:⟨ 1189:… 1183:⟩ 1161:⟨ 1127:⟩ 1112:⟨ 1091:ϕ 1010:≡ 985:⋮ 915:≡ 836:≡ 748:∈ 716:ϕ 685:⟩ 663:⟨ 617:∏ 560:… 464:⟩ 449:⟨ 53:in 1981. 3144:See also 308:divides 196:′ 68:Overview 3215:0606517 3207:2007663 3134:PARI/GP 2293:. Set 1576:modulo 763:to the 24:algebra 3213:  3205:  2866:. If 1511:where 982:  979:  708:, say 142:whose 26:, the 3237:arXiv 3203:JSTOR 1083:then 34:over 3092:and 368:ring 49:and 3247:doi 3233:140 3193:doi 2056:gcd 1953:gcd 1856:gcd 1037:mod 942:mod 863:mod 704:to 374:). 171:gcd 43:GCD 19:In 3278:: 3245:, 3231:, 3211:MR 3209:, 3201:, 3189:36 3187:, 3177:; 3104:. 1845:: 1317:. 64:. 3249:: 3239:: 3195:: 3094:C 3080:B 3077:, 3074:A 3054:1 3048:, 3045:0 3039:) 3036:x 3033:( 3030:b 3010:) 3007:x 3004:( 3001:a 2979:m 2975:) 2971:x 2968:( 2965:b 2945:0 2942:= 2937:m 2933:) 2929:x 2926:( 2921:i 2917:b 2896:0 2893:= 2890:) 2887:x 2884:( 2879:i 2875:b 2864:i 2850:1 2844:= 2839:m 2835:) 2831:x 2828:( 2823:i 2819:b 2808:i 2794:1 2791:= 2786:1 2778:d 2774:q 2769:) 2765:x 2762:( 2757:i 2753:b 2732:0 2729:= 2726:) 2723:x 2720:( 2715:i 2711:b 2690:1 2682:d 2678:q 2655:d 2651:q 2627:) 2624:x 2621:( 2616:i 2612:p 2605:+ 2602:) 2599:x 2596:( 2591:i 2587:b 2563:. 2560:) 2554:) 2551:x 2548:( 2543:s 2539:p 2532:+ 2529:) 2526:x 2523:( 2518:m 2513:s 2509:b 2505:, 2499:, 2493:) 2490:x 2487:( 2482:1 2478:p 2471:+ 2468:) 2465:x 2462:( 2457:m 2452:1 2448:b 2444:( 2441:= 2438:) 2433:m 2429:) 2425:x 2422:( 2419:b 2416:( 2368:m 2364:) 2360:x 2357:( 2354:b 2334:2 2330:/ 2326:) 2323:1 2315:d 2311:q 2307:( 2304:= 2301:m 2281:1 2275:, 2272:0 2266:) 2263:x 2260:( 2257:b 2237:R 2231:) 2228:x 2225:( 2222:b 2200:q 2195:F 2173:) 2170:x 2167:( 2164:a 2136:. 2133:) 2130:x 2127:( 2122:i 2118:p 2112:C 2106:i 2098:= 2095:) 2092:1 2086:) 2083:x 2080:( 2077:a 2074:, 2071:) 2068:x 2065:( 2062:f 2059:( 2033:, 2030:) 2027:x 2024:( 2019:i 2015:p 2009:B 2003:i 1995:= 1992:) 1989:1 1986:+ 1983:) 1980:x 1977:( 1974:a 1971:, 1968:) 1965:x 1962:( 1959:f 1956:( 1930:, 1927:) 1924:x 1921:( 1916:i 1912:p 1906:A 1900:i 1892:= 1889:) 1886:) 1883:x 1880:( 1877:a 1874:, 1871:) 1868:x 1865:( 1862:f 1859:( 1833:) 1830:x 1827:( 1824:f 1801:, 1798:} 1795:1 1792:= 1789:) 1786:x 1783:( 1778:i 1774:a 1767:i 1764:{ 1761:= 1758:C 1735:, 1732:} 1729:1 1723:= 1720:) 1717:x 1714:( 1709:i 1705:a 1698:i 1695:{ 1692:= 1689:B 1666:, 1663:} 1660:0 1657:= 1654:) 1651:x 1648:( 1643:i 1639:a 1632:i 1629:{ 1626:= 1623:A 1600:) 1597:x 1594:( 1589:i 1585:p 1564:) 1561:x 1558:( 1555:a 1535:) 1532:x 1529:( 1524:i 1520:a 1496:, 1493:s 1490:, 1484:, 1481:2 1478:, 1475:1 1472:= 1469:i 1461:} 1458:1 1455:, 1452:1 1446:, 1443:0 1440:{ 1434:) 1431:x 1428:( 1423:i 1419:a 1395:1 1389:, 1386:0 1380:) 1377:x 1374:( 1371:a 1348:R 1342:) 1339:x 1336:( 1333:a 1303:d 1299:q 1278:) 1275:x 1272:( 1267:i 1263:p 1242:) 1236:) 1233:x 1230:( 1225:s 1221:p 1214:+ 1211:) 1208:x 1205:( 1200:s 1196:g 1192:, 1186:, 1180:) 1177:x 1174:( 1169:1 1165:p 1158:+ 1155:) 1152:x 1149:( 1144:1 1140:g 1136:( 1133:= 1130:) 1124:) 1121:x 1118:( 1115:f 1109:+ 1106:) 1103:x 1100:( 1097:g 1094:( 1064:, 1060:) 1057:) 1054:x 1051:( 1046:s 1042:p 1034:( 1029:) 1026:x 1023:( 1018:s 1014:g 1001:) 998:x 995:( 992:g 969:, 965:) 962:) 959:x 956:( 951:2 947:p 939:( 934:) 931:x 928:( 923:2 919:g 906:) 903:x 900:( 897:g 890:, 886:) 883:) 880:x 877:( 872:1 868:p 860:( 855:) 852:x 849:( 844:1 840:g 827:) 824:x 821:( 818:g 791:) 788:x 785:( 780:i 776:p 765:s 751:R 745:) 742:x 739:( 736:g 706:S 702:R 682:) 679:x 676:( 671:i 667:p 658:] 655:x 652:[ 647:q 642:F 632:s 627:1 624:= 621:i 613:= 610:S 596:d 582:) 579:x 576:( 571:s 567:p 563:, 557:, 554:) 551:x 548:( 543:2 539:p 535:, 532:) 529:x 526:( 521:1 517:p 496:) 493:x 490:( 487:f 461:) 458:x 455:( 452:f 444:] 441:x 438:[ 433:q 428:F 420:= 417:R 394:) 391:x 388:( 385:f 354:) 351:x 348:( 345:f 325:) 322:x 319:( 316:f 296:) 293:x 290:( 287:g 267:) 264:x 261:( 258:g 238:) 235:x 232:( 229:f 209:) 206:) 203:x 200:( 193:f 189:, 186:) 183:x 180:( 177:f 174:( 167:/ 163:) 160:x 157:( 154:f 128:q 123:F 111:n 97:) 94:x 91:( 88:f

Index

computational
algebra
polynomials
finite fields
GCD
David G. Cantor
Hans Zassenhaus
Berlekamp's algorithm
computer algebra systems
square-free polynomial
irreducible polynomial
ring
unique factorisation domain
factor ring
direct product
Euclidean domain
Euclidean algorithm
discrete logarithms
public key cryptography
index calculus method
PARI/GP
factorcantor()
Polynomial factorization
Factorization of polynomials over finite fields
Cantor, David G.
Zassenhaus, Hans
Mathematics of Computation
doi
10.1090/S0025-5718-1981-0606517-5
JSTOR

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