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Trapdoor function

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129: 32: 235:" solution would be to try dividing 6895601 by many prime numbers until finding the answer. However, if one is told that 1931 is one of the numbers, one can find the answer by entering "6895601 Ă· 1931" into any calculator. This example is not a sturdy trapdoor function – modern computers can guess all of the possible answers within a second – but this sample problem could be improved by 308:(these are frequently used interchangeably, which is incorrect). A backdoor is a deliberate mechanism that is added to a cryptographic algorithm (e.g., a key pair generation algorithm, digital signing algorithm, etc.) or operating system, for example, that permits one or more unauthorized parties to bypass or subvert the security of the system in some fashion. 1715: 266:
coined the term. Several function classes had been proposed, and it soon became obvious that trapdoor functions are harder to find than was initially thought. For example, an early suggestion was to use schemes based on the
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and its key. It is trivial to change the padlock from open to closed without using the key, by pushing the shackle into the lock mechanism. Opening the padlock easily, however, requires the key to be used. Here the key
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known to be trapdoor functions, because there is no known "trapdoor" information about the group that enables the efficient computation of discrete logarithms.
2598: 2308: 1710:{\displaystyle a\equiv x^{2}{\pmod {p}},a\equiv y^{2}{\pmod {q}},c\equiv 1{\pmod {p}},c\equiv 0{\pmod {q}},d\equiv 0{\pmod {p}},d\equiv 1{\pmod {q}}} 2726: 2721: 2450: 2629: 2623: 231:
An example of a simple mathematical trapdoor is "6895601 is the product of two prime numbers. What are those numbers?" A typical "
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families of functions. Both are written as exponentiation modulo a composite number, and both are related to the problem of
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In the following two examples, we always assume that it is difficult to factorize a large composite number (see
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that is easy to compute in one direction, yet difficult to compute in the opposite direction (finding its
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Bellare, M (June 1998). "Many-to-one trapdoor functions and their relation to public-key cryptosystems".
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A trapdoor in cryptography has the very specific aforementioned meaning and is not to be confused with a
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If each function in the collection above is a one-way permutation, then the collection is also called a
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This article is about the mathematical cryptography function. For the method of bypassing security, see
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are subsets of binary strings {0, 1}, satisfying the following conditions:
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As of 2004, the best known trapdoor function (family) candidates are the
2706: 2438: 2055: 2050:. Lecture Notes in Computer Science. Vol. 1462. pp. 283–298. 128: 2460: 1316:, and kept confidential to the adversary. The problem is to compute 31: 2767: 2701: 2572: 2567: 2562: 2465: 2443: 199:
is a trapdoor function, then there exists some secret information
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Goldwasser's lecture notes, 2.3.2; Lindell's notes, p. 17, Ex. 1.
220: 2711: 2547: 2504: 2472: 2455: 614:, for any PPT algorithm, the probability to correctly invert 228:
is the trapdoor and the padlock is the trapdoor function.
2640: 2494: 1309:{\displaystyle p\equiv 3{\pmod {4}},q\equiv 3{\pmod {4}}} 1152: 497:, there exists a PPT algorithm that correctly computes 2253:
Introduction to Cryptography Lecture Notes (Fall 2008)
1995: 1975: 1933: 1891: 1878:{\displaystyle y\equiv a^{\frac {q+1}{4}}{\pmod {q}}} 1829: 1816:{\displaystyle x\equiv a^{\frac {p+1}{4}}{\pmod {p}}} 1767: 1747: 1727: 1527: 1435: 1411: 1362: 1342: 1322: 1252: 1232: 1212: 1183: 1163: 1073: 1038: 984: 964: 944: 882: 853: 796: 773: 740: 720: 700: 293:(either modulo a prime or in a group defined over an 148:
can be efficiently computed, i.e., in probabilistic
385:There exists a probabilistic polynomial time (PPT) 271:. This turned out rather quickly to be unsuitable. 132:The idea of trapdoor function. A trapdoor function 56:. Unsourced material may be challenged and removed. 2001: 1981: 1961: 1919: 1877: 1815: 1753: 1733: 1709: 1513: 1417: 1397: 1348: 1328: 1308: 1238: 1218: 1198: 1169: 1142:{\displaystyle x=y^{d}\mod n=x^{ed}\mod n=x\mod n} 1141: 1059: 1024: 970: 950: 930: 868: 836: 779: 755: 726: 706: 2113:Pass's notes, def 56.1; Dodis's def 7, lecture 1. 594:). That is, given trapdoor, it is easy to invert. 464:, there also exists a PPT algorithm that outputs 2795: 1149:. Its hardness follows from the RSA assumption. 2302: 2143: 263: 152:. However, the computation of the inverse of 2316: 457:. Each trapdoor can be efficiently sampled. 237:using the product of two much larger primes 2309: 2295: 2173: 1721:for more details. Note that given primes 1514:{\displaystyle cx+dy,cx-dy,-cx+dy,-cx-dy} 1135: 1134: 1120: 1119: 1095: 1094: 1009: 1008: 827: 826: 289:Functions related to the hardness of the 246:in the mid-1970s with the publication of 242:Trapdoor functions came to prominence in 116:Learn how and when to remove this message 1398:{\displaystyle a\equiv z^{2}{\pmod {n}}} 127: 2161:IEEE Transactions on Information Theory 2045: 1405:. The trapdoor is the factorization of 1025:{\displaystyle d=e^{-1}\mod {\phi (n)}} 938:can be computed. With this the inverse 156:is generally hard, unless the trapdoor 2796: 2209: 1425:. With the trapdoor, the solutions of 1177:be a large composite number such that 2290: 2229: 2095:Goldwasser's lecture notes, def. 2.16 248:asymmetric (or public-key) encryption 2630:Naccache–Stern knapsack cryptosystem 1962:{\displaystyle q\equiv 3{\pmod {4}}} 1920:{\displaystyle p\equiv 3{\pmod {4}}} 1153:Rabin's quadratic residue assumption 54:adding citations to reliable sources 25: 2266: 2048:Advances in Cryptology — CRYPTO '98 1951: 1909: 1867: 1805: 1699: 1671: 1643: 1615: 1587: 1552: 1387: 1298: 1270: 931:{\displaystyle \phi (n)=(p-1)(q-1)} 13: 2131:Goldwasser's lecture notes, 2.3.4. 14: 2820: 2249: 837:{\displaystyle f(x)=x^{e}\mod n.} 689: 140:can be generated by an algorithm 2189: 2153:"New directions in cryptography" 30: 2661:Discrete logarithm cryptography 1944: 1902: 1860: 1798: 1692: 1664: 1636: 1608: 1580: 1545: 1380: 1291: 1263: 1130: 1115: 1090: 1004: 822: 517:, there exists a PPT algorithm 41:needs additional citations for 2125: 2116: 2107: 2098: 2089: 2080: 2039: 2030: 1955: 1945: 1913: 1903: 1871: 1861: 1809: 1799: 1703: 1693: 1675: 1665: 1647: 1637: 1619: 1609: 1591: 1581: 1556: 1546: 1391: 1381: 1302: 1292: 1274: 1264: 1054: 1048: 1019: 1013: 925: 913: 910: 898: 892: 886: 806: 800: 750: 744: 1: 2213:Lecture Notes on Cryptography 2137: 1969:guarantee that the solutions 694:In this example, the inverse 389:algorithm Gen s.t. Gen(1) = ( 311: 2676:Non-commutative cryptography 2104:Ostrovsky, pp. 6–10, def. 11 166:theoretical computer science 7: 2773:Identity-based cryptography 2666:Elliptic-curve cryptography 2270:Foundations of Cryptography 2233:Foundations of Cryptography 2012: 1246:are large primes such that 677: 486:can be efficiently sampled. 264:Diffie & Hellman (1976) 10: 2825: 291:discrete logarithm problem 195:In mathematical terms, if 18: 16:One-way cryptographic tool 2778:Post-quantum cryptography 2735: 2727:Post-Quantum Cryptography 2694: 2653: 2581: 2523: 2404: 2331: 2324: 1719:Chinese remainder theorem 440:is some polynomial. Each 2809:Cryptographic primitives 2193:A Course in Cryptography 2184:10.1109/TIT.1976.1055638 2024: 847:If the factorization of 765:Euler's totient function 756:{\displaystyle \phi (n)} 215:, it is easy to compute 2671:Hash-based cryptography 2318:Public-key cryptography 2086:Pass's Notes, def. 56.1 190:public-key cryptography 188:and are widely used in 2804:Theory of cryptography 2003: 1983: 1963: 1921: 1885:. Here the conditions 1879: 1817: 1755: 1735: 1711: 1515: 1419: 1399: 1350: 1330: 1310: 1240: 1220: 1200: 1171: 1143: 1061: 1060:{\displaystyle y=f(x)} 1026: 972: 952: 932: 870: 838: 781: 757: 728: 708: 161: 2333:Integer factorization 2009:can be well defined. 2004: 1984: 1964: 1922: 1880: 1818: 1756: 1736: 1712: 1516: 1420: 1400: 1351: 1331: 1311: 1241: 1221: 1201: 1172: 1144: 1062: 1027: 973: 953: 933: 871: 839: 782: 758: 729: 709: 684:Integer factorization 419:∈ {0, 1} satisfies | 131: 1993: 1973: 1931: 1889: 1827: 1765: 1745: 1725: 1525: 1433: 1409: 1360: 1340: 1320: 1250: 1230: 1210: 1199:{\displaystyle n=pq} 1181: 1161: 1071: 1036: 982: 962: 942: 880: 869:{\displaystyle n=pq} 851: 794: 771: 738: 718: 698: 672:trapdoor permutation 636:), find a pre-image 568:), and then we have 50:improve this article 21:Backdoor (computing) 2636:Three-pass protocol 2230:Ostrovsky, Rafail, 2210:Goldwasser, Shafi, 787:) is the trapdoor: 605:, without trapdoor 359:), in which all of 320:is a collection of 284:prime factorization 65:"Trapdoor function" 2406:Discrete logarithm 2056:10.1007/bfb0055735 2036:Ostrovsky, pp. 6–9 1999: 1979: 1959: 1917: 1875: 1813: 1751: 1731: 1707: 1511: 1415: 1395: 1346: 1326: 1306: 1236: 1216: 1196: 1167: 1139: 1057: 1022: 968: 948: 928: 866: 834: 777: 753: 724: 704: 269:subset sum problem 203:, such that given 162: 136:with its trapdoor 2791: 2790: 2743:Digital signature 2686:Trapdoor function 2649: 2648: 2366:Goldwasser–Micali 2267:Lindell, Yehuda, 2250:Dodis, Yevgeniy, 2065:978-3-540-64892-5 2002:{\displaystyle y} 1982:{\displaystyle x} 1856: 1794: 1754:{\displaystyle q} 1734:{\displaystyle p} 1418:{\displaystyle n} 1349:{\displaystyle a} 1329:{\displaystyle z} 1239:{\displaystyle q} 1219:{\displaystyle p} 1170:{\displaystyle n} 1032:, and then given 971:{\displaystyle e} 951:{\displaystyle d} 780:{\displaystyle n} 727:{\displaystyle e} 707:{\displaystyle d} 666:)) is negligible. 453:corresponding to 322:one-way functions 318:trapdoor function 186:one-way functions 174:trapdoor function 126: 125: 118: 100: 2816: 2632: 2533: 2528: 2488:signature scheme 2391:Okamoto–Uchiyama 2329: 2328: 2311: 2304: 2297: 2288: 2287: 2283: 2282: 2280: 2275: 2263: 2262: 2260: 2246: 2245: 2243: 2238: 2226: 2225: 2223: 2218: 2206: 2205: 2203: 2198: 2186: 2177: 2157: 2132: 2129: 2123: 2120: 2114: 2111: 2105: 2102: 2096: 2093: 2087: 2084: 2078: 2077: 2043: 2037: 2034: 2019:One-way function 2008: 2006: 2005: 2000: 1988: 1986: 1985: 1980: 1968: 1966: 1965: 1960: 1958: 1926: 1924: 1923: 1918: 1916: 1884: 1882: 1881: 1876: 1874: 1858: 1857: 1852: 1841: 1822: 1820: 1819: 1814: 1812: 1796: 1795: 1790: 1779: 1760: 1758: 1757: 1752: 1740: 1738: 1737: 1732: 1716: 1714: 1713: 1708: 1706: 1678: 1650: 1622: 1594: 1578: 1577: 1559: 1543: 1542: 1520: 1518: 1517: 1512: 1429:can be given as 1424: 1422: 1421: 1416: 1404: 1402: 1401: 1396: 1394: 1378: 1377: 1355: 1353: 1352: 1347: 1335: 1333: 1332: 1327: 1315: 1313: 1312: 1307: 1305: 1277: 1245: 1243: 1242: 1237: 1225: 1223: 1222: 1217: 1205: 1203: 1202: 1197: 1176: 1174: 1173: 1168: 1148: 1146: 1145: 1140: 1114: 1113: 1089: 1088: 1066: 1064: 1063: 1058: 1031: 1029: 1028: 1023: 1003: 1002: 978:can be computed 977: 975: 974: 969: 957: 955: 954: 949: 937: 935: 934: 929: 875: 873: 872: 867: 843: 841: 840: 835: 821: 820: 786: 784: 783: 778: 762: 760: 759: 754: 733: 731: 730: 725: 713: 711: 710: 705: 477:. That is, each 121: 114: 110: 107: 101: 99: 58: 34: 26: 2824: 2823: 2819: 2818: 2817: 2815: 2814: 2813: 2794: 2793: 2792: 2787: 2731: 2695:Standardization 2690: 2645: 2628: 2577: 2525:Lattice/SVP/CVP 2519: 2400: 2346:Blum–Goldwasser 2320: 2315: 2278: 2276: 2273: 2258: 2256: 2241: 2239: 2236: 2221: 2219: 2216: 2201: 2199: 2196: 2155: 2140: 2135: 2130: 2126: 2121: 2117: 2112: 2108: 2103: 2099: 2094: 2090: 2085: 2081: 2066: 2044: 2040: 2035: 2031: 2027: 2015: 1994: 1991: 1990: 1974: 1971: 1970: 1943: 1932: 1929: 1928: 1901: 1890: 1887: 1886: 1859: 1842: 1840: 1836: 1828: 1825: 1824: 1797: 1780: 1778: 1774: 1766: 1763: 1762: 1746: 1743: 1742: 1726: 1723: 1722: 1691: 1663: 1635: 1607: 1579: 1573: 1569: 1544: 1538: 1534: 1526: 1523: 1522: 1434: 1431: 1430: 1410: 1407: 1406: 1379: 1373: 1369: 1361: 1358: 1357: 1341: 1338: 1337: 1321: 1318: 1317: 1290: 1262: 1251: 1248: 1247: 1231: 1228: 1227: 1211: 1208: 1207: 1182: 1179: 1178: 1162: 1159: 1158: 1155: 1106: 1102: 1084: 1080: 1072: 1069: 1068: 1037: 1034: 1033: 995: 991: 983: 980: 979: 963: 960: 959: 943: 940: 939: 881: 878: 877: 876:is known, then 852: 849: 848: 816: 812: 795: 792: 791: 772: 769: 768: 739: 736: 735: 719: 716: 715: 699: 696: 695: 692: 680: 661: 648: 631: 622: 613: 589: 576: 567: 554: 533: 505: 485: 476: 448: 427: 418: 401: 380: 371: 350: 341: 332: 314: 150:polynomial time 122: 111: 105: 102: 59: 57: 47: 35: 24: 17: 12: 11: 5: 2822: 2812: 2811: 2806: 2789: 2788: 2786: 2785: 2780: 2775: 2770: 2765: 2760: 2755: 2750: 2745: 2739: 2737: 2733: 2732: 2730: 2729: 2724: 2719: 2714: 2709: 2704: 2698: 2696: 2692: 2691: 2689: 2688: 2683: 2678: 2673: 2668: 2663: 2657: 2655: 2651: 2650: 2647: 2646: 2644: 2643: 2638: 2633: 2626: 2624:Merkle–Hellman 2621: 2616: 2611: 2606: 2601: 2596: 2591: 2585: 2583: 2579: 2578: 2576: 2575: 2570: 2565: 2560: 2555: 2550: 2545: 2539: 2537: 2521: 2520: 2518: 2517: 2512: 2507: 2502: 2497: 2492: 2491: 2490: 2480: 2475: 2470: 2469: 2468: 2463: 2453: 2448: 2447: 2446: 2441: 2431: 2426: 2421: 2416: 2410: 2408: 2402: 2401: 2399: 2398: 2393: 2388: 2383: 2378: 2373: 2371:Naccache–Stern 2368: 2363: 2358: 2353: 2348: 2343: 2337: 2335: 2326: 2322: 2321: 2314: 2313: 2306: 2299: 2291: 2285: 2284: 2264: 2247: 2227: 2207: 2190:Pass, Rafael, 2187: 2175:10.1.1.37.9720 2168:(6): 644–654, 2139: 2136: 2134: 2133: 2124: 2115: 2106: 2097: 2088: 2079: 2064: 2038: 2028: 2026: 2023: 2022: 2021: 2014: 2011: 1998: 1978: 1957: 1954: 1950: 1947: 1942: 1939: 1936: 1915: 1912: 1908: 1905: 1900: 1897: 1894: 1873: 1870: 1866: 1863: 1855: 1851: 1848: 1845: 1839: 1835: 1832: 1811: 1808: 1804: 1801: 1793: 1789: 1786: 1783: 1777: 1773: 1770: 1761:, we can find 1750: 1730: 1705: 1702: 1698: 1695: 1690: 1687: 1684: 1681: 1677: 1674: 1670: 1667: 1662: 1659: 1656: 1653: 1649: 1646: 1642: 1639: 1634: 1631: 1628: 1625: 1621: 1618: 1614: 1611: 1606: 1603: 1600: 1597: 1593: 1590: 1586: 1583: 1576: 1572: 1568: 1565: 1562: 1558: 1555: 1551: 1548: 1541: 1537: 1533: 1530: 1510: 1507: 1504: 1501: 1498: 1495: 1492: 1489: 1486: 1483: 1480: 1477: 1474: 1471: 1468: 1465: 1462: 1459: 1456: 1453: 1450: 1447: 1444: 1441: 1438: 1414: 1393: 1390: 1386: 1383: 1376: 1372: 1368: 1365: 1345: 1325: 1304: 1301: 1297: 1294: 1289: 1286: 1283: 1280: 1276: 1273: 1269: 1266: 1261: 1258: 1255: 1235: 1215: 1195: 1192: 1189: 1186: 1166: 1154: 1151: 1138: 1133: 1129: 1126: 1123: 1118: 1112: 1109: 1105: 1101: 1098: 1093: 1087: 1083: 1079: 1076: 1067:, we can find 1056: 1053: 1050: 1047: 1044: 1041: 1021: 1018: 1015: 1012: 1007: 1001: 998: 994: 990: 987: 967: 947: 927: 924: 921: 918: 915: 912: 909: 906: 903: 900: 897: 894: 891: 888: 885: 865: 862: 859: 856: 845: 844: 833: 830: 825: 819: 815: 811: 808: 805: 802: 799: 776: 752: 749: 746: 743: 723: 703: 691: 690:RSA assumption 688: 679: 676: 668: 667: 657: 644: 627: 618: 609: 595: 585: 572: 563: 550: 529: 507: 501: 487: 481: 472: 458: 449:is called the 444: 423: 414: 397: 376: 367: 346: 337: 328: 313: 310: 295:elliptic curve 250:techniques by 124: 123: 38: 36: 29: 15: 9: 6: 4: 3: 2: 2821: 2810: 2807: 2805: 2802: 2801: 2799: 2784: 2781: 2779: 2776: 2774: 2771: 2769: 2766: 2764: 2761: 2759: 2756: 2754: 2751: 2749: 2746: 2744: 2741: 2740: 2738: 2734: 2728: 2725: 2723: 2720: 2718: 2715: 2713: 2710: 2708: 2705: 2703: 2700: 2699: 2697: 2693: 2687: 2684: 2682: 2679: 2677: 2674: 2672: 2669: 2667: 2664: 2662: 2659: 2658: 2656: 2652: 2642: 2639: 2637: 2634: 2631: 2627: 2625: 2622: 2620: 2617: 2615: 2612: 2610: 2607: 2605: 2602: 2600: 2597: 2595: 2592: 2590: 2587: 2586: 2584: 2580: 2574: 2571: 2569: 2566: 2564: 2561: 2559: 2556: 2554: 2551: 2549: 2546: 2544: 2541: 2540: 2538: 2536: 2531: 2526: 2522: 2516: 2513: 2511: 2508: 2506: 2503: 2501: 2498: 2496: 2493: 2489: 2486: 2485: 2484: 2481: 2479: 2476: 2474: 2471: 2467: 2464: 2462: 2459: 2458: 2457: 2454: 2452: 2449: 2445: 2442: 2440: 2437: 2436: 2435: 2432: 2430: 2427: 2425: 2422: 2420: 2417: 2415: 2412: 2411: 2409: 2407: 2403: 2397: 2396:Schmidt–Samoa 2394: 2392: 2389: 2387: 2384: 2382: 2379: 2377: 2374: 2372: 2369: 2367: 2364: 2362: 2359: 2357: 2356:DamgĂ„rd–Jurik 2354: 2352: 2351:Cayley–Purser 2349: 2347: 2344: 2342: 2339: 2338: 2336: 2334: 2330: 2327: 2323: 2319: 2312: 2307: 2305: 2300: 2298: 2293: 2292: 2289: 2272: 2271: 2265: 2255: 2254: 2248: 2235: 2234: 2228: 2215: 2214: 2208: 2195: 2194: 2188: 2185: 2181: 2176: 2171: 2167: 2163: 2162: 2154: 2150: 2146: 2142: 2141: 2128: 2119: 2110: 2101: 2092: 2083: 2075: 2071: 2067: 2061: 2057: 2053: 2049: 2042: 2033: 2029: 2020: 2017: 2016: 2010: 1996: 1976: 1952: 1948: 1940: 1937: 1934: 1910: 1906: 1898: 1895: 1892: 1868: 1864: 1853: 1849: 1846: 1843: 1837: 1833: 1830: 1806: 1802: 1791: 1787: 1784: 1781: 1775: 1771: 1768: 1748: 1728: 1720: 1700: 1696: 1688: 1685: 1682: 1679: 1672: 1668: 1660: 1657: 1654: 1651: 1644: 1640: 1632: 1629: 1626: 1623: 1616: 1612: 1604: 1601: 1598: 1595: 1588: 1584: 1574: 1570: 1566: 1563: 1560: 1553: 1549: 1539: 1535: 1531: 1528: 1508: 1505: 1502: 1499: 1496: 1493: 1490: 1487: 1484: 1481: 1478: 1475: 1472: 1469: 1466: 1463: 1460: 1457: 1454: 1451: 1448: 1445: 1442: 1439: 1436: 1428: 1412: 1388: 1384: 1374: 1370: 1366: 1363: 1343: 1323: 1299: 1295: 1287: 1284: 1281: 1278: 1271: 1267: 1259: 1256: 1253: 1233: 1213: 1193: 1190: 1187: 1184: 1164: 1150: 1136: 1131: 1127: 1124: 1121: 1116: 1110: 1107: 1103: 1099: 1096: 1091: 1085: 1081: 1077: 1074: 1051: 1045: 1042: 1039: 1016: 1010: 1005: 999: 996: 992: 988: 985: 965: 945: 922: 919: 916: 907: 904: 901: 895: 889: 883: 863: 860: 857: 854: 831: 828: 823: 817: 813: 809: 803: 797: 790: 789: 788: 774: 766: 747: 741: 721: 701: 687: 685: 675: 673: 665: 660: 656: 652: 647: 643: 639: 635: 630: 626: 623:(i.e., given 621: 617: 612: 608: 604: 600: 596: 593: 588: 584: 580: 575: 571: 566: 562: 558: 553: 549: 545: 541: 537: 532: 528: 524: 521:s.t. for any 520: 516: 512: 508: 504: 500: 496: 492: 488: 484: 480: 475: 471: 467: 463: 459: 456: 452: 447: 443: 439: 435: 431: 426: 422: 417: 413: 410:∩ {0, 1} and 409: 405: 400: 396: 392: 388: 384: 383: 382: 379: 375: 370: 366: 362: 358: 354: 349: 345: 340: 336: 331: 327: 323: 319: 309: 307: 302: 300: 296: 292: 287: 285: 281: 277: 272: 270: 265: 261: 257: 253: 249: 245: 240: 238: 234: 229: 227: 222: 219:. Consider a 218: 214: 210: 206: 202: 198: 193: 191: 187: 183: 179: 175: 171: 167: 159: 155: 151: 147: 143: 139: 135: 130: 120: 117: 109: 98: 95: 91: 88: 84: 81: 77: 74: 70: 67: â€“  66: 62: 61:Find sources: 55: 51: 45: 44: 39:This article 37: 33: 28: 27: 22: 2783:OpenPGP card 2763:Web of trust 2685: 2419:Cramer–Shoup 2277:, retrieved 2269: 2257:, retrieved 2252: 2240:, retrieved 2232: 2220:, retrieved 2212: 2200:, retrieved 2192: 2165: 2159: 2127: 2118: 2109: 2100: 2091: 2082: 2047: 2041: 2032: 1426: 1156: 846: 693: 681: 671: 669: 663: 658: 654: 650: 645: 641: 637: 633: 628: 624: 619: 615: 610: 606: 602: 598: 591: 586: 582: 578: 573: 569: 564: 560: 556: 551: 547: 543: 539: 535: 530: 526: 522: 518: 514: 510: 502: 498: 494: 490: 482: 478: 473: 469: 465: 461: 460:Given input 454: 450: 445: 441: 437: 436:), in which 433: 429: 424: 420: 415: 411: 407: 403: 398: 394: 390: 386: 377: 373: 368: 364: 360: 356: 352: 347: 343: 338: 334: 329: 325: 317: 315: 303: 298: 288: 273: 244:cryptography 241: 230: 225: 216: 212: 208: 204: 200: 196: 194: 173: 170:cryptography 163: 157: 153: 145: 141: 137: 133: 112: 103: 93: 86: 79: 72: 60: 48:Please help 43:verification 40: 2753:Fingerprint 2717:NSA Suite B 2681:RSA problem 2558:NTRUEncrypt 2279:17 December 2259:17 December 2242:27 November 2222:25 November 2202:27 November 2149:Hellman, M. 233:brute-force 2798:Categories 2707:IEEE P1363 2325:Algorithms 2145:Diffie, W. 2138:References 1356:such that 640:such that 312:Definition 262:. Indeed, 76:newspapers 2170:CiteSeerX 2074:215825522 1938:≡ 1896:≡ 1834:≡ 1772:≡ 1686:≡ 1658:≡ 1630:≡ 1602:≡ 1567:≡ 1532:≡ 1503:− 1494:− 1473:− 1461:− 1367:≡ 1285:≡ 1257:≡ 1011:ϕ 997:− 920:− 905:− 884:ϕ 742:ϕ 160:is given. 106:July 2013 2768:Key size 2702:CRYPTREC 2619:McEliece 2573:RLWE-SIG 2568:RLWE-KEX 2563:NTRUSign 2376:Paillier 2151:(1976), 2013:See also 1521:, where 1206:, where 678:Examples 597:For any 509:For any 489:For any 451:trapdoor 387:sampling 333: : 306:backdoor 178:function 2614:Lamport 2594:CEILIDH 2553:NewHope 2500:Schnorr 2483:ElGamal 2461:Ed25519 2341:Benaloh 734:modulo 428:| < 402:) with 256:Hellman 221:padlock 182:inverse 90:scholar 2736:Topics 2712:NESSIE 2654:Theory 2582:Others 2439:X25519 2172:  2072:  2062:  1717:. See 1336:given 534:, let 297:) are 260:Merkle 258:, and 252:Diffie 211:) and 92:  85:  78:  71:  63:  2548:Kyber 2543:BLISS 2505:SPEKE 2473:ECMQV 2466:Ed448 2456:EdDSA 2451:ECDSA 2381:Rabin 2274:(PDF) 2237:(PDF) 2217:(PDF) 2197:(PDF) 2156:(PDF) 2070:S2CID 2025:Notes 280:Rabin 176:is a 97:JSTOR 83:books 2748:OAEP 2722:CNSA 2599:EPOC 2444:X448 2434:ECDH 2281:2015 2261:2015 2244:2015 2224:2015 2204:2015 2060:ISBN 1989:and 1927:and 1823:and 1741:and 1226:and 1157:Let 653:) = 581:) = 278:and 172:, a 168:and 69:news 2758:PKI 2641:XTR 2609:IES 2604:HFE 2535:SIS 2530:LWE 2515:STS 2510:SRP 2495:MQV 2478:EKE 2429:DSA 2414:BLS 2386:RSA 2361:GMR 2180:doi 2052:doi 1949:mod 1907:mod 1865:mod 1803:mod 1697:mod 1669:mod 1641:mod 1613:mod 1585:mod 1550:mod 1385:mod 1296:mod 1268:mod 1132:mod 1117:mod 1092:mod 1006:mod 958:of 824:mod 767:of 714:of 686:). 651:x' 638:x' 559:), 351:} ( 299:not 276:RSA 164:In 142:Gen 52:by 2800:: 2589:AE 2424:DH 2178:, 2166:22 2164:, 2158:, 2147:; 2068:. 2058:. 674:. 601:∈ 546:, 542:( 538:= 525:∈ 513:∈ 493:∈ 468:∈ 406:∈ 393:, 372:, 363:, 355:∈ 342:→ 324:{ 316:A 286:. 254:, 239:. 192:. 144:. 2532:/ 2527:/ 2310:e 2303:t 2296:v 2182:: 2076:. 2054:: 1997:y 1977:x 1956:) 1953:4 1946:( 1941:3 1935:q 1914:) 1911:4 1904:( 1899:3 1893:p 1872:) 1869:q 1862:( 1854:4 1850:1 1847:+ 1844:q 1838:a 1831:y 1810:) 1807:p 1800:( 1792:4 1788:1 1785:+ 1782:p 1776:a 1769:x 1749:q 1729:p 1704:) 1701:q 1694:( 1689:1 1683:d 1680:, 1676:) 1673:p 1666:( 1661:0 1655:d 1652:, 1648:) 1645:q 1638:( 1633:0 1627:c 1624:, 1620:) 1617:p 1610:( 1605:1 1599:c 1596:, 1592:) 1589:q 1582:( 1575:2 1571:y 1564:a 1561:, 1557:) 1554:p 1547:( 1540:2 1536:x 1529:a 1509:y 1506:d 1500:x 1497:c 1491:, 1488:y 1485:d 1482:+ 1479:x 1476:c 1470:, 1467:y 1464:d 1458:x 1455:c 1452:, 1449:y 1446:d 1443:+ 1440:x 1437:c 1427:z 1413:n 1392:) 1389:n 1382:( 1375:2 1371:z 1364:a 1344:a 1324:z 1303:) 1300:4 1293:( 1288:3 1282:q 1279:, 1275:) 1272:4 1265:( 1260:3 1254:p 1234:q 1214:p 1194:q 1191:p 1188:= 1185:n 1165:n 1137:n 1128:x 1125:= 1122:n 1111:d 1108:e 1104:x 1100:= 1097:n 1086:d 1082:y 1078:= 1075:x 1055:) 1052:x 1049:( 1046:f 1043:= 1040:y 1020:) 1017:n 1014:( 1000:1 993:e 989:= 986:d 966:e 946:d 926:) 923:1 917:q 914:( 911:) 908:1 902:p 899:( 896:= 893:) 890:n 887:( 864:q 861:p 858:= 855:n 832:. 829:n 818:e 814:x 810:= 807:) 804:x 801:( 798:f 775:n 763:( 751:) 748:n 745:( 722:e 702:d 664:x 662:( 659:k 655:f 649:( 646:k 642:f 634:x 632:( 629:k 625:f 620:k 616:f 611:k 607:t 603:K 599:k 592:x 590:( 587:k 583:f 579:y 577:( 574:k 570:f 565:k 561:t 557:x 555:( 552:k 548:f 544:k 540:A 536:y 531:k 527:D 523:x 519:A 515:K 511:k 506:. 503:k 499:f 495:K 491:k 483:k 479:D 474:k 470:D 466:x 462:k 455:k 446:k 442:t 438:p 434:n 432:( 430:p 425:k 421:t 416:k 412:t 408:K 404:k 399:k 395:t 391:k 378:k 374:R 369:k 365:D 361:K 357:K 353:k 348:k 344:R 339:k 335:D 330:k 326:f 226:t 217:x 213:t 209:x 207:( 205:f 201:t 197:f 158:t 154:f 146:f 138:t 134:f 119:) 113:( 108:) 104:( 94:· 87:· 80:· 73:· 46:. 23:.

Index

Backdoor (computing)

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polynomial time
theoretical computer science
cryptography
function
inverse
one-way functions
public-key cryptography
padlock
brute-force
using the product of two much larger primes
cryptography
asymmetric (or public-key) encryption
Diffie
Hellman
Merkle
Diffie & Hellman (1976)
subset sum problem

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