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takeover","\u002Fdocs\u002Fv3\u002Fconcepts\u002Faccount-takeover","1.docs\u002Fv3\u002F6.concepts\u002F16.account-takeover",{"title":157,"path":158,"stem":159},"Account sharing","\u002Fdocs\u002Fv3\u002Fconcepts\u002Faccount-sharing","1.docs\u002Fv3\u002F6.concepts\u002F17.account-sharing",{"title":161,"path":162,"stem":163},"Fake account","\u002Fdocs\u002Fv3\u002Fconcepts\u002Ffake-account","1.docs\u002Fv3\u002F6.concepts\u002F18.fake-account",{"title":165,"path":166,"stem":167},"Scraping","\u002Fdocs\u002Fv3\u002Fconcepts\u002Fscraping","1.docs\u002Fv3\u002F6.concepts\u002F19.scraping",{"title":169,"path":170,"stem":171},"Linked accounts","\u002Fdocs\u002Fv3\u002Fconcepts\u002Flinked-accounts","1.docs\u002Fv3\u002F6.concepts\u002F20.linked-accounts",{"title":173,"path":174,"stem":175},"New IP","\u002Fdocs\u002Fv3\u002Fconcepts\u002Fip","1.docs\u002Fv3\u002F6.concepts\u002F21.ip",{"title":177,"path":178,"stem":179},"Anonymizing 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protection.md",{"type":201,"value":202,"toc":1595},"minimark",[203,207,230,244,247,252,280,284,288,292,307,771,775,778,1129,1133,1147,1150,1158,1162,1177,1572,1581,1584,1591],[204,205,31],"h1",{"id":206},"login-protection",[208,209,210,211,215,216,219,220,223,224,226,227,229],"p",{},"The login evaluation has three verdicts: ",[212,213,214],"code",{},"allow",", ",[212,217,218],{},"deny",", and ",[212,221,222],{},"challenge",". The ",[212,225,214],{}," and ",[212,228,218],{}," verdicts are simple cases.",[208,231,232,233,235,236,240,241,243],{},"The ",[212,234,222],{}," verdict requires a bit more work to ensure it's not bypassed. The one rule is: ",[237,238,239],"strong",{},"don't issue a session or token while a challenge is outstanding."," If the verdict is ",[212,242,222],{},", the user gets nothing until your server confirms the challenge completed.",[208,245,246],{},"Login and signup protection are the foundation of every other guide. Once you have those two down, you can build on them with different policies and checks for any other use case.",[248,249,251],"h2",{"id":250},"what-this-protects-against","What this protects against",[253,254,255,263,270,273],"ul",{},[256,257,258,259,262],"li",{},"A user triggers a login challenge, closes the tab, and hits ",[212,260,261],{},"\u002Flogin"," again. If a challenge never blocks the session, the second attempt just works.",[256,264,265,266,269],{},"The client sends one user to Rupt and authenticates as a different one. Your server sees ",[212,267,268],{},"verdict: allow"," and trusts it.",[256,271,272],{},"A stolen-credential login that should have been challenged sails through because the server never confirmed the outcome.",[256,274,275,276,279],{},"An attacker replays the post-challenge success URL — or guesses an ",[212,277,278],{},"evaluation_id"," whose challenge already completed — to mint a session without passing a challenge of their own.",[248,281,283],{"id":282},"the-flow","The flow",[285,286],"mermaid-diagram",{"code":287},"sequenceDiagram\n  actor U as User\n  participant C as Login form\n  participant S as Your server\n  participant R as Rupt\n  participant X as Challenge UI\n\n  U->>C: Submits login form (email, password)\n  C->>R: evaluate.login({ user, email })\n  R-->>C: { evaluation_id, redirect? }\n  C->>S: POST \u002Flogin { credentials, evaluation_id }\n  S->>R: GET \u002Fv3\u002Fevaluations\u002F{evaluation_id}\n  R-->>S: { verdict, user, challenge }\n  Note over S: Check password, run integrity check\n\n  alt verdict = deny\n    S-->>C: Reject (401)\n    C-->>U: Show error\n  else verdict = allow\n    S->>S: Start a session\n    S-->>U: Logged in\n  else verdict = challenge\n    S-->>C: { redirect } (no session yet)\n    C-->>U: Navigate to challenge URL\n    U->>X: Complete challenge\n    X->>S: Redirect to success_url?evaluation=…\n    S->>R: POST \u002Fv3\u002Fevaluations\u002F{evaluation_id}\u002Fconsume\n    R-->>S: { challenge.status, createdAt } — or 409 if already used\n    Note over S: Confirm the consume succeeded,\u003Cbr\u002F>challenge.status = completed, and the evaluation is fresh\n    S->>S: Start a session\n    S-->>U: Logged in\n  end\n",[248,289,291],{"id":290},"step-1-call-evaluate-at-login","Step 1: Call evaluate at login",[208,293,294,295,298,299,302,303,306],{},"Pass the ",[212,296,297],{},"user"," id and ",[212,300,301],{},"email"," (and ",[212,304,305],{},"phone"," if you have it).",[308,309,310,613,702],"client-platform",{},[311,312,314],"template",{"v-slot:web":313},"",[315,316,320],"pre",{"className":317,"code":318,"language":319,"meta":313,"style":313},"language-js shiki shiki-themes material-theme-lighter one-dark-pro monokai","import Rupt from \"@ruptjs\u002Fclient\";\n\nconst rupt = new Rupt({ clientId: \"your_client_id\" });\n\nconst loginEval = await rupt.evaluate.login({\n  user: user.id,\n  email: form.email,\n});\n\n\u002F\u002F POST \u002Flogin to your server with the credentials and the evaluation ID\nawait fetch(\"\u002Flogin\", {\n  method: \"POST\",\n  body: JSON.stringify({\n    ...credentials,\n    evaluation_id: loginEval?.evaluation_id,\n  }),\n});\n","js",[212,321,322,353,360,411,416,447,466,483,493,498,505,528,545,565,577,594,604],{"__ignoreMap":313},[323,324,327,331,335,338,342,346,349],"span",{"class":325,"line":326},"line",1,[323,328,330],{"class":329},"sAPXc","import",[323,332,334],{"class":333},"seeE2"," Rupt",[323,336,337],{"class":329}," from",[323,339,341],{"class":340},"s9QZx"," \"",[323,343,345],{"class":344},"siibJ","@ruptjs\u002Fclient",[323,347,348],{"class":340},"\"",[323,350,352],{"class":351},"shEKG",";\n",[323,354,356],{"class":325,"line":355},2,[323,357,359],{"emptyLinePlaceholder":358},true,"\n",[323,361,363,367,371,375,379,382,386,389,393,396,398,401,403,406,409],{"class":325,"line":362},3,[323,364,366],{"class":365},"sHm3x","const",[323,368,370],{"class":369},"sZ9uN"," rupt",[323,372,374],{"class":373},"sut_7"," =",[323,376,378],{"class":377},"srTuz"," new",[323,380,334],{"class":381},"sjp9t",[323,383,385],{"class":384},"sJCYa","(",[323,387,388],{"class":351},"{",[323,390,392],{"class":391},"sUwfj"," clientId",[323,394,395],{"class":351},":",[323,397,341],{"class":340},[323,399,400],{"class":344},"your_client_id",[323,402,348],{"class":340},[323,404,405],{"class":351}," }",[323,407,408],{"class":384},")",[323,410,352],{"class":351},[323,412,414],{"class":325,"line":413},4,[323,415,359],{"emptyLinePlaceholder":358},[323,417,419,421,424,426,429,431,434,437,439,442,444],{"class":325,"line":418},5,[323,420,366],{"class":365},[323,422,423],{"class":369}," loginEval",[323,425,374],{"class":373},[323,427,428],{"class":329}," await",[323,430,370],{"class":369},[323,432,433],{"class":351},".",[323,435,436],{"class":369},"evaluate",[323,438,433],{"class":351},[323,440,441],{"class":381},"login",[323,443,385],{"class":384},[323,445,446],{"class":351},"{\n",[323,448,450,453,455,458,460,463],{"class":325,"line":449},6,[323,451,452],{"class":391},"  user",[323,454,395],{"class":351},[323,456,457],{"class":369}," user",[323,459,433],{"class":351},[323,461,462],{"class":333},"id",[323,464,465],{"class":351},",\n",[323,467,469,472,474,477,479,481],{"class":325,"line":468},7,[323,470,471],{"class":391},"  email",[323,473,395],{"class":351},[323,475,476],{"class":369}," form",[323,478,433],{"class":351},[323,480,301],{"class":333},[323,482,465],{"class":351},[323,484,486,489,491],{"class":325,"line":485},8,[323,487,488],{"class":351},"}",[323,490,408],{"class":384},[323,492,352],{"class":351},[323,494,496],{"class":325,"line":495},9,[323,497,359],{"emptyLinePlaceholder":358},[323,499,501],{"class":325,"line":500},10,[323,502,504],{"class":503},"s42Qa","\u002F\u002F POST \u002Flogin to your server with the credentials and the evaluation ID\n",[323,506,508,511,514,516,518,520,522,525],{"class":325,"line":507},11,[323,509,510],{"class":329},"await",[323,512,513],{"class":381}," fetch",[323,515,385],{"class":384},[323,517,348],{"class":340},[323,519,261],{"class":344},[323,521,348],{"class":340},[323,523,524],{"class":351},",",[323,526,527],{"class":351}," {\n",[323,529,531,534,536,538,541,543],{"class":325,"line":530},12,[323,532,533],{"class":391},"  method",[323,535,395],{"class":351},[323,537,341],{"class":340},[323,539,540],{"class":344},"POST",[323,542,348],{"class":340},[323,544,465],{"class":351},[323,546,548,551,553,556,558,561,563],{"class":325,"line":547},13,[323,549,550],{"class":391},"  body",[323,552,395],{"class":351},[323,554,555],{"class":369}," JSON",[323,557,433],{"class":351},[323,559,560],{"class":381},"stringify",[323,562,385],{"class":384},[323,564,446],{"class":351},[323,566,568,572,575],{"class":325,"line":567},14,[323,569,571],{"class":570},"sKfv_","    ...",[323,573,574],{"class":333},"credentials",[323,576,465],{"class":351},[323,578,580,583,585,587,590,592],{"class":325,"line":579},15,[323,581,582],{"class":391},"    evaluation_id",[323,584,395],{"class":351},[323,586,423],{"class":369},[323,588,589],{"class":351},"?.",[323,591,278],{"class":333},[323,593,465],{"class":351},[323,595,597,600,602],{"class":325,"line":596},16,[323,598,599],{"class":351},"  }",[323,601,408],{"class":384},[323,603,465],{"class":351},[323,605,607,609,611],{"class":325,"line":606},17,[323,608,488],{"class":351},[323,610,408],{"class":384},[323,612,352],{"class":351},[311,614,615],{"v-slot:ios":313},[315,616,620],{"className":617,"code":618,"language":619,"meta":313,"style":313},"language-swift shiki shiki-themes material-theme-lighter one-dark-pro monokai","let response = try await rupt.evaluate(\n  action: \"login\",\n  user: user.id,\n  email: form.email\n)\n\n\u002F\u002F POST evaluation.evaluationId to your server with the credentials\n","swift",[212,621,622,648,663,676,688,693,697],{"__ignoreMap":313},[323,623,624,628,631,634,637,639,642,645],{"class":325,"line":326},[323,625,627],{"class":626},"s2NTT","let",[323,629,630],{"class":384}," response ",[323,632,633],{"class":570},"=",[323,635,636],{"class":329}," try",[323,638,428],{"class":329},[323,640,641],{"class":384}," rupt.",[323,643,436],{"class":644},"sh6BQ",[323,646,647],{"class":351},"(\n",[323,649,650,653,655,657,659,661],{"class":325,"line":355},[323,651,652],{"class":644},"  action",[323,654,395],{"class":351},[323,656,341],{"class":340},[323,658,441],{"class":344},[323,660,348],{"class":340},[323,662,465],{"class":384},[323,664,665,667,669,672,674],{"class":325,"line":362},[323,666,452],{"class":644},[323,668,395],{"class":351},[323,670,671],{"class":384}," user.",[323,673,462],{"class":333},[323,675,465],{"class":384},[323,677,678,680,682,685],{"class":325,"line":413},[323,679,471],{"class":644},[323,681,395],{"class":351},[323,683,684],{"class":384}," form.",[323,686,687],{"class":333},"email\n",[323,689,690],{"class":325,"line":418},[323,691,692],{"class":351},")\n",[323,694,695],{"class":325,"line":449},[323,696,359],{"emptyLinePlaceholder":358},[323,698,699],{"class":325,"line":468},[323,700,701],{"class":503},"\u002F\u002F POST evaluation.evaluationId to your server with the credentials\n",[311,703,704],{"v-slot:android":313},[315,705,709],{"className":706,"code":707,"language":708,"meta":313,"style":313},"language-kotlin shiki shiki-themes material-theme-lighter one-dark-pro monokai","val response = rupt.evaluate(\n  action = \"login\",\n  user = user.id,\n  email = form.email,\n)\n\n\u002F\u002F POST response.evaluationId to your server with the credentials\n","kotlin",[212,710,711,726,738,748,758,762,766],{"__ignoreMap":313},[323,712,713,716,718,720,722,724],{"class":325,"line":326},[323,714,715],{"class":377},"val",[323,717,630],{"class":384},[323,719,633],{"class":373},[323,721,641],{"class":384},[323,723,436],{"class":381},[323,725,647],{"class":384},[323,727,728,731,733,736],{"class":325,"line":355},[323,729,730],{"class":384},"  action ",[323,732,633],{"class":373},[323,734,735],{"class":344}," \"login\"",[323,737,465],{"class":384},[323,739,740,743,745],{"class":325,"line":362},[323,741,742],{"class":384},"  user ",[323,744,633],{"class":373},[323,746,747],{"class":384}," user.id,\n",[323,749,750,753,755],{"class":325,"line":413},[323,751,752],{"class":384},"  email ",[323,754,633],{"class":373},[323,756,757],{"class":384}," form.email,\n",[323,759,760],{"class":325,"line":418},[323,761,692],{"class":384},[323,763,764],{"class":325,"line":449},[323,765,359],{"emptyLinePlaceholder":358},[323,767,768],{"class":325,"line":468},[323,769,770],{"class":503},"\u002F\u002F POST response.evaluationId to your server with the credentials\n",[248,772,774],{"id":773},"step-2-handle-the-verdict-on-your-server","Step 2: Handle the verdict on your server",[208,776,777],{},"Your server checks the password, fetches the evaluation, runs the integrity check (the action and user match what you expected), then branches on the verdict. On a challenge it issues nothing and hands back the redirect.",[315,779,783],{"className":780,"code":781,"language":782,"meta":313,"style":313},"language-ts shiki shiki-themes material-theme-lighter one-dark-pro monokai","\u002F\u002F POST \u002Flogin\nif (!checkPassword(credentials)) return reject(\"Invalid credentials\");\n\nconst evaluation = await rupt.getEvaluation(evaluation_id);\n\n\u002F\u002F Integrity check — block tampering before anything else\nif (evaluation.action !== \"login\") return reject(\"Action mismatch\");\nif (evaluation.user?.id !== user.id) return reject(\"Identity mismatch\");\n\nif (evaluation.verdict === \"deny\") {\n  return reject(\"Login denied\");\n}\n\nif (evaluation.verdict === \"allow\") {\n  return { session: startSession(user) };\n}\n\nif (evaluation.verdict === \"challenge\") {\n  \u002F\u002F Don't start a session. Send the user to the challenge first.\n  return { redirect: evaluation.redirect };\n}\n","ts",[212,784,785,790,830,834,860,864,869,912,955,959,985,1006,1011,1015,1039,1063,1067,1071,1096,1102,1124],{"__ignoreMap":313},[323,786,787],{"class":325,"line":326},[323,788,789],{"class":503},"\u002F\u002F POST \u002Flogin\n",[323,791,792,795,798,801,804,806,808,811,814,817,819,821,824,826,828],{"class":325,"line":355},[323,793,794],{"class":329},"if",[323,796,797],{"class":384}," (",[323,799,800],{"class":373},"!",[323,802,803],{"class":381},"checkPassword",[323,805,385],{"class":384},[323,807,574],{"class":333},[323,809,810],{"class":384},")) ",[323,812,813],{"class":329},"return",[323,815,816],{"class":381}," reject",[323,818,385],{"class":384},[323,820,348],{"class":340},[323,822,823],{"class":344},"Invalid credentials",[323,825,348],{"class":340},[323,827,408],{"class":384},[323,829,352],{"class":351},[323,831,832],{"class":325,"line":362},[323,833,359],{"emptyLinePlaceholder":358},[323,835,836,838,841,843,845,847,849,852,854,856,858],{"class":325,"line":413},[323,837,366],{"class":365},[323,839,840],{"class":369}," evaluation",[323,842,374],{"class":373},[323,844,428],{"class":329},[323,846,370],{"class":369},[323,848,433],{"class":351},[323,850,851],{"class":381},"getEvaluation",[323,853,385],{"class":384},[323,855,278],{"class":333},[323,857,408],{"class":384},[323,859,352],{"class":351},[323,861,862],{"class":325,"line":418},[323,863,359],{"emptyLinePlaceholder":358},[323,865,866],{"class":325,"line":449},[323,867,868],{"class":503},"\u002F\u002F Integrity check — block tampering before anything else\n",[323,870,871,873,875,878,880,883,886,888,890,892,895,897,899,901,903,906,908,910],{"class":325,"line":468},[323,872,794],{"class":329},[323,874,797],{"class":384},[323,876,877],{"class":369},"evaluation",[323,879,433],{"class":351},[323,881,882],{"class":333},"action",[323,884,885],{"class":373}," !==",[323,887,341],{"class":340},[323,889,441],{"class":344},[323,891,348],{"class":340},[323,893,894],{"class":384},") ",[323,896,813],{"class":329},[323,898,816],{"class":381},[323,900,385],{"class":384},[323,902,348],{"class":340},[323,904,905],{"class":344},"Action mismatch",[323,907,348],{"class":340},[323,909,408],{"class":384},[323,911,352],{"class":351},[323,913,914,916,918,920,922,924,926,928,930,932,934,936,938,940,942,944,946,949,951,953],{"class":325,"line":485},[323,915,794],{"class":329},[323,917,797],{"class":384},[323,919,877],{"class":369},[323,921,433],{"class":351},[323,923,297],{"class":369},[323,925,589],{"class":351},[323,927,462],{"class":333},[323,929,885],{"class":373},[323,931,457],{"class":369},[323,933,433],{"class":351},[323,935,462],{"class":333},[323,937,894],{"class":384},[323,939,813],{"class":329},[323,941,816],{"class":381},[323,943,385],{"class":384},[323,945,348],{"class":340},[323,947,948],{"class":344},"Identity mismatch",[323,950,348],{"class":340},[323,952,408],{"class":384},[323,954,352],{"class":351},[323,956,957],{"class":325,"line":495},[323,958,359],{"emptyLinePlaceholder":358},[323,960,961,963,965,967,969,972,975,977,979,981,983],{"class":325,"line":500},[323,962,794],{"class":329},[323,964,797],{"class":384},[323,966,877],{"class":369},[323,968,433],{"class":351},[323,970,971],{"class":333},"verdict",[323,973,974],{"class":373}," ===",[323,976,341],{"class":340},[323,978,218],{"class":344},[323,980,348],{"class":340},[323,982,894],{"class":384},[323,984,446],{"class":351},[323,986,987,990,992,995,997,1000,1002,1004],{"class":325,"line":507},[323,988,989],{"class":329},"  return",[323,991,816],{"class":381},[323,993,385],{"class":994},"s2Cpd",[323,996,348],{"class":340},[323,998,999],{"class":344},"Login denied",[323,1001,348],{"class":340},[323,1003,408],{"class":994},[323,1005,352],{"class":351},[323,1007,1008],{"class":325,"line":530},[323,1009,1010],{"class":351},"}\n",[323,1012,1013],{"class":325,"line":547},[323,1014,359],{"emptyLinePlaceholder":358},[323,1016,1017,1019,1021,1023,1025,1027,1029,1031,1033,1035,1037],{"class":325,"line":567},[323,1018,794],{"class":329},[323,1020,797],{"class":384},[323,1022,877],{"class":369},[323,1024,433],{"class":351},[323,1026,971],{"class":333},[323,1028,974],{"class":373},[323,1030,341],{"class":340},[323,1032,214],{"class":344},[323,1034,348],{"class":340},[323,1036,894],{"class":384},[323,1038,446],{"class":351},[323,1040,1041,1043,1046,1049,1051,1054,1056,1058,1060],{"class":325,"line":579},[323,1042,989],{"class":329},[323,1044,1045],{"class":351}," {",[323,1047,1048],{"class":391}," session",[323,1050,395],{"class":351},[323,1052,1053],{"class":381}," startSession",[323,1055,385],{"class":994},[323,1057,297],{"class":333},[323,1059,894],{"class":994},[323,1061,1062],{"class":351},"};\n",[323,1064,1065],{"class":325,"line":596},[323,1066,1010],{"class":351},[323,1068,1069],{"class":325,"line":606},[323,1070,359],{"emptyLinePlaceholder":358},[323,1072,1074,1076,1078,1080,1082,1084,1086,1088,1090,1092,1094],{"class":325,"line":1073},18,[323,1075,794],{"class":329},[323,1077,797],{"class":384},[323,1079,877],{"class":369},[323,1081,433],{"class":351},[323,1083,971],{"class":333},[323,1085,974],{"class":373},[323,1087,341],{"class":340},[323,1089,222],{"class":344},[323,1091,348],{"class":340},[323,1093,894],{"class":384},[323,1095,446],{"class":351},[323,1097,1099],{"class":325,"line":1098},19,[323,1100,1101],{"class":503},"  \u002F\u002F Don't start a session. Send the user to the challenge first.\n",[323,1103,1105,1107,1109,1112,1114,1116,1118,1121],{"class":325,"line":1104},20,[323,1106,989],{"class":329},[323,1108,1045],{"class":351},[323,1110,1111],{"class":391}," redirect",[323,1113,395],{"class":351},[323,1115,840],{"class":369},[323,1117,433],{"class":351},[323,1119,1120],{"class":333},"redirect",[323,1122,1123],{"class":351}," };\n",[323,1125,1127],{"class":325,"line":1126},21,[323,1128,1010],{"class":351},[248,1130,1132],{"id":1131},"step-3-configure-the-challenge-success-url","Step 3: Configure the challenge success URL",[208,1134,1135,1136,1139,1140,1143,1144,433],{},"In the Rupt dashboard, on the relevant Challenge Config (",[212,1137,1138],{},"Policies -> Edit -> Challenge Config","), set ",[237,1141,1142],{},"Success URL"," to the page that finishes login. For example: ",[212,1145,1146],{},"https:\u002F\u002Fyourapp.com\u002Flogin\u002Fcomplete",[208,1148,1149],{},"When the user passes, Rupt redirects there with the evaluation ID appended:",[315,1151,1156],{"className":1152,"code":1154,"language":1155},[1153],"language-text","https:\u002F\u002Fyourapp.com\u002Flogin\u002Fcomplete?evaluation=68f…\n","text",[212,1157,1154],{"__ignoreMap":313},[248,1159,1161],{"id":1160},"step-4-consume-the-evaluation-and-start-the-session","Step 4: Consume the evaluation and start the session",[208,1163,1164,1165,1168,1169,1172,1173,1176],{},"Your ",[212,1166,1167],{},"\u002Flogin\u002Fcomplete"," route takes the evaluation ID from the URL and ",[237,1170,1171],{},"consumes"," it. Consuming is a single-use, atomic claim: Rupt marks the evaluation spent and returns it in one step, so the same success URL can never start a second session. The first call wins; a replay throws ",[212,1174,1175],{},"409",". Start the session only if the consume succeeds, the challenge completed, and the evaluation is still fresh.",[315,1178,1180],{"className":780,"code":1179,"language":782,"meta":313,"style":313},"\u002F\u002F POST \u002Flogin\u002Fcomplete\nconst { evaluation_id } = req.body;\n\nlet evaluation;\ntry {\n  \u002F\u002F Single-use: the first call wins, a replay throws 409.\n  evaluation = await rupt.consumeEvaluation(evaluation_id);\n} catch (err) {\n  if (err.status === 409) return reject(\"This login link was already used\");\n  \u002F\u002F Network or 5xx — fail open, allow the login to proceed. Worth logging.\n  return { session: startSession(evaluation.user) };\n}\n\nif (evaluation.action !== \"login\") return reject(\"Action mismatch\");\n\n\u002F\u002F Cap time on challenge to 10 mins (as an example).\nif (Date.now() - new Date(evaluation.createdAt).getTime() >= 10 * 60 * 1000) {\n  return reject(\"Login session expired\");\n}\n\nif (evaluation.challenge?.status !== \"completed\") {\n  return reject(\"Challenge not completed\");\n}\n\nreturn { session: startSession(evaluation.user) };\n",[212,1181,1182,1187,1210,1214,1222,1229,1234,1258,1274,1313,1318,1342,1346,1350,1388,1392,1397,1461,1480,1484,1488,1517,1537,1542,1547],{"__ignoreMap":313},[323,1183,1184],{"class":325,"line":326},[323,1185,1186],{"class":503},"\u002F\u002F POST \u002Flogin\u002Fcomplete\n",[323,1188,1189,1191,1193,1196,1198,1200,1203,1205,1208],{"class":325,"line":355},[323,1190,366],{"class":365},[323,1192,1045],{"class":351},[323,1194,1195],{"class":369}," evaluation_id",[323,1197,405],{"class":351},[323,1199,374],{"class":373},[323,1201,1202],{"class":369}," req",[323,1204,433],{"class":351},[323,1206,1207],{"class":333},"body",[323,1209,352],{"class":351},[323,1211,1212],{"class":325,"line":362},[323,1213,359],{"emptyLinePlaceholder":358},[323,1215,1216,1218,1220],{"class":325,"line":413},[323,1217,627],{"class":365},[323,1219,840],{"class":333},[323,1221,352],{"class":351},[323,1223,1224,1227],{"class":325,"line":418},[323,1225,1226],{"class":329},"try",[323,1228,527],{"class":351},[323,1230,1231],{"class":325,"line":449},[323,1232,1233],{"class":503},"  \u002F\u002F Single-use: the first call wins, a replay throws 409.\n",[323,1235,1236,1239,1241,1243,1245,1247,1250,1252,1254,1256],{"class":325,"line":468},[323,1237,1238],{"class":333},"  evaluation",[323,1240,374],{"class":373},[323,1242,428],{"class":329},[323,1244,370],{"class":369},[323,1246,433],{"class":351},[323,1248,1249],{"class":381},"consumeEvaluation",[323,1251,385],{"class":994},[323,1253,278],{"class":333},[323,1255,408],{"class":994},[323,1257,352],{"class":351},[323,1259,1260,1262,1265,1267,1270,1272],{"class":325,"line":485},[323,1261,488],{"class":351},[323,1263,1264],{"class":329}," catch",[323,1266,797],{"class":384},[323,1268,1269],{"class":333},"err",[323,1271,894],{"class":384},[323,1273,446],{"class":351},[323,1275,1276,1279,1281,1283,1285,1288,1290,1294,1296,1298,1300,1302,1304,1307,1309,1311],{"class":325,"line":495},[323,1277,1278],{"class":329},"  if",[323,1280,797],{"class":994},[323,1282,1269],{"class":369},[323,1284,433],{"class":351},[323,1286,1287],{"class":333},"status",[323,1289,974],{"class":373},[323,1291,1293],{"class":1292},"s4ofd"," 409",[323,1295,894],{"class":994},[323,1297,813],{"class":329},[323,1299,816],{"class":381},[323,1301,385],{"class":994},[323,1303,348],{"class":340},[323,1305,1306],{"class":344},"This login link was already used",[323,1308,348],{"class":340},[323,1310,408],{"class":994},[323,1312,352],{"class":351},[323,1314,1315],{"class":325,"line":500},[323,1316,1317],{"class":503},"  \u002F\u002F Network or 5xx — fail open, allow the login to proceed. Worth logging.\n",[323,1319,1320,1322,1324,1326,1328,1330,1332,1334,1336,1338,1340],{"class":325,"line":507},[323,1321,989],{"class":329},[323,1323,1045],{"class":351},[323,1325,1048],{"class":391},[323,1327,395],{"class":351},[323,1329,1053],{"class":381},[323,1331,385],{"class":994},[323,1333,877],{"class":369},[323,1335,433],{"class":351},[323,1337,297],{"class":333},[323,1339,894],{"class":994},[323,1341,1062],{"class":351},[323,1343,1344],{"class":325,"line":530},[323,1345,1010],{"class":351},[323,1347,1348],{"class":325,"line":547},[323,1349,359],{"emptyLinePlaceholder":358},[323,1351,1352,1354,1356,1358,1360,1362,1364,1366,1368,1370,1372,1374,1376,1378,1380,1382,1384,1386],{"class":325,"line":567},[323,1353,794],{"class":329},[323,1355,797],{"class":384},[323,1357,877],{"class":369},[323,1359,433],{"class":351},[323,1361,882],{"class":333},[323,1363,885],{"class":373},[323,1365,341],{"class":340},[323,1367,441],{"class":344},[323,1369,348],{"class":340},[323,1371,894],{"class":384},[323,1373,813],{"class":329},[323,1375,816],{"class":381},[323,1377,385],{"class":384},[323,1379,348],{"class":340},[323,1381,905],{"class":344},[323,1383,348],{"class":340},[323,1385,408],{"class":384},[323,1387,352],{"class":351},[323,1389,1390],{"class":325,"line":579},[323,1391,359],{"emptyLinePlaceholder":358},[323,1393,1394],{"class":325,"line":596},[323,1395,1396],{"class":503},"\u002F\u002F Cap time on challenge to 10 mins (as an example).\n",[323,1398,1399,1401,1403,1406,1408,1411,1414,1417,1419,1422,1424,1426,1428,1431,1433,1435,1438,1440,1443,1446,1449,1452,1454,1457,1459],{"class":325,"line":606},[323,1400,794],{"class":329},[323,1402,797],{"class":384},[323,1404,1405],{"class":369},"Date",[323,1407,433],{"class":351},[323,1409,1410],{"class":381},"now",[323,1412,1413],{"class":384},"() ",[323,1415,1416],{"class":373},"-",[323,1418,378],{"class":377},[323,1420,1421],{"class":381}," Date",[323,1423,385],{"class":384},[323,1425,877],{"class":369},[323,1427,433],{"class":351},[323,1429,1430],{"class":333},"createdAt",[323,1432,408],{"class":384},[323,1434,433],{"class":351},[323,1436,1437],{"class":381},"getTime",[323,1439,1413],{"class":384},[323,1441,1442],{"class":373},">=",[323,1444,1445],{"class":1292}," 10",[323,1447,1448],{"class":373}," *",[323,1450,1451],{"class":1292}," 60",[323,1453,1448],{"class":373},[323,1455,1456],{"class":1292}," 1000",[323,1458,894],{"class":384},[323,1460,446],{"class":351},[323,1462,1463,1465,1467,1469,1471,1474,1476,1478],{"class":325,"line":1073},[323,1464,989],{"class":329},[323,1466,816],{"class":381},[323,1468,385],{"class":994},[323,1470,348],{"class":340},[323,1472,1473],{"class":344},"Login session expired",[323,1475,348],{"class":340},[323,1477,408],{"class":994},[323,1479,352],{"class":351},[323,1481,1482],{"class":325,"line":1098},[323,1483,1010],{"class":351},[323,1485,1486],{"class":325,"line":1104},[323,1487,359],{"emptyLinePlaceholder":358},[323,1489,1490,1492,1494,1496,1498,1500,1502,1504,1506,1508,1511,1513,1515],{"class":325,"line":1126},[323,1491,794],{"class":329},[323,1493,797],{"class":384},[323,1495,877],{"class":369},[323,1497,433],{"class":351},[323,1499,222],{"class":369},[323,1501,589],{"class":351},[323,1503,1287],{"class":333},[323,1505,885],{"class":373},[323,1507,341],{"class":340},[323,1509,1510],{"class":344},"completed",[323,1512,348],{"class":340},[323,1514,894],{"class":384},[323,1516,446],{"class":351},[323,1518,1520,1522,1524,1526,1528,1531,1533,1535],{"class":325,"line":1519},22,[323,1521,989],{"class":329},[323,1523,816],{"class":381},[323,1525,385],{"class":994},[323,1527,348],{"class":340},[323,1529,1530],{"class":344},"Challenge not completed",[323,1532,348],{"class":340},[323,1534,408],{"class":994},[323,1536,352],{"class":351},[323,1538,1540],{"class":325,"line":1539},23,[323,1541,1010],{"class":351},[323,1543,1545],{"class":325,"line":1544},24,[323,1546,359],{"emptyLinePlaceholder":358},[323,1548,1550,1552,1554,1556,1558,1560,1562,1564,1566,1568,1570],{"class":325,"line":1549},25,[323,1551,813],{"class":329},[323,1553,1045],{"class":351},[323,1555,1048],{"class":391},[323,1557,395],{"class":351},[323,1559,1053],{"class":381},[323,1561,385],{"class":384},[323,1563,877],{"class":369},[323,1565,433],{"class":351},[323,1567,297],{"class":333},[323,1569,894],{"class":384},[323,1571,1062],{"class":351},[208,1573,1574,1575,1577,1578,1580],{},"The session starts here, never at ",[212,1576,261],{}," when a challenge was issued. Consuming rather than just reading is what makes it safe: an attacker who captures the success URL — or guesses an ",[212,1579,278],{}," — finds it already spent, never completed, or expired.",[1582,1583],"hr",{},[208,1585,1586,1587,1590],{},"Pair this with ",[1588,1589,27],"a",{"href":28}," and you've covered both ends of authentication. 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The allow and deny verdicts are simple cases.","md",{},"---\ntitle: Login protection\n---\n\n# Login protection\n\nThe login evaluation has three verdicts: `allow`, `deny`, and `challenge`. The `allow` and `deny` verdicts are simple cases.\n\nThe `challenge` verdict requires a bit more work to ensure it's not bypassed. The one rule is: **don't issue a session or token while a challenge is outstanding.** If the verdict is `challenge`, the user gets nothing until your server confirms the challenge completed.\n\nLogin and signup protection are the foundation of every other guide. Once you have those two down, you can build on them with different policies and checks for any other use case.\n\n## What this protects against\n\n- A user triggers a login challenge, closes the tab, and hits `\u002Flogin` again. If a challenge never blocks the session, the second attempt just works.\n- The client sends one user to Rupt and authenticates as a different one. Your server sees `verdict: allow` and trusts it.\n- A stolen-credential login that should have been challenged sails through because the server never confirmed the outcome.\n- An attacker replays the post-challenge success URL — or guesses an `evaluation_id` whose challenge already completed — to mint a session without passing a challenge of their own.\n\n## The flow\n\n\u003C!-- prettier-ignore-start -->\n::MermaidDiagram\n---\ncode: |\n  sequenceDiagram\n    actor U as User\n    participant C as Login form\n    participant S as Your server\n    participant R as Rupt\n    participant X as Challenge UI\n\n    U->>C: Submits login form (email, password)\n    C->>R: evaluate.login({ user, email })\n    R-->>C: { evaluation_id, redirect? }\n    C->>S: POST \u002Flogin { credentials, evaluation_id }\n    S->>R: GET \u002Fv3\u002Fevaluations\u002F{evaluation_id}\n    R-->>S: { verdict, user, challenge }\n    Note over S: Check password, run integrity check\n\n    alt verdict = deny\n      S-->>C: Reject (401)\n      C-->>U: Show error\n    else verdict = allow\n      S->>S: Start a session\n      S-->>U: Logged in\n    else verdict = challenge\n      S-->>C: { redirect } (no session yet)\n      C-->>U: Navigate to challenge URL\n      U->>X: Complete challenge\n      X->>S: Redirect to success_url?evaluation=…\n      S->>R: POST \u002Fv3\u002Fevaluations\u002F{evaluation_id}\u002Fconsume\n      R-->>S: { challenge.status, createdAt } — or 409 if already used\n      Note over S: Confirm the consume succeeded,\u003Cbr\u002F>challenge.status = completed, and the evaluation is fresh\n      S->>S: Start a session\n      S-->>U: Logged in\n    end\n---\n::\n\u003C!-- prettier-ignore-end -->\n\n## Step 1: Call evaluate at login\n\nPass the `user` id and `email` (and `phone` if you have it).\n\n::ClientPlatform\n\n#web\n\n```js\nimport Rupt from \"@ruptjs\u002Fclient\";\n\nconst rupt = new Rupt({ clientId: \"your_client_id\" });\n\nconst loginEval = await rupt.evaluate.login({\n  user: user.id,\n  email: form.email,\n});\n\n\u002F\u002F POST \u002Flogin to your server with the credentials and the evaluation ID\nawait fetch(\"\u002Flogin\", {\n  method: \"POST\",\n  body: JSON.stringify({\n    ...credentials,\n    evaluation_id: loginEval?.evaluation_id,\n  }),\n});\n```\n\n#ios\n\n```swift\nlet response = try await rupt.evaluate(\n  action: \"login\",\n  user: user.id,\n  email: form.email\n)\n\n\u002F\u002F POST evaluation.evaluationId to your server with the credentials\n```\n\n#android\n\n```kotlin\nval response = rupt.evaluate(\n  action = \"login\",\n  user = user.id,\n  email = form.email,\n)\n\n\u002F\u002F POST response.evaluationId to your server with the credentials\n```\n\n::\n\n## Step 2: Handle the verdict on your server\n\nYour server checks the password, fetches the evaluation, runs the integrity check (the action and user match what you expected), then branches on the verdict. On a challenge it issues nothing and hands back the redirect.\n\n```ts\n\u002F\u002F POST \u002Flogin\nif (!checkPassword(credentials)) return reject(\"Invalid credentials\");\n\nconst evaluation = await rupt.getEvaluation(evaluation_id);\n\n\u002F\u002F Integrity check — block tampering before anything else\nif (evaluation.action !== \"login\") return reject(\"Action mismatch\");\nif (evaluation.user?.id !== user.id) return reject(\"Identity mismatch\");\n\nif (evaluation.verdict === \"deny\") {\n  return reject(\"Login denied\");\n}\n\nif (evaluation.verdict === \"allow\") {\n  return { session: startSession(user) };\n}\n\nif (evaluation.verdict === \"challenge\") {\n  \u002F\u002F Don't start a session. Send the user to the challenge first.\n  return { redirect: evaluation.redirect };\n}\n```\n\n## Step 3: Configure the challenge success URL\n\nIn the Rupt dashboard, on the relevant Challenge Config (`Policies -> Edit -> Challenge Config`), set **Success URL** to the page that finishes login. For example: `https:\u002F\u002Fyourapp.com\u002Flogin\u002Fcomplete`.\n\nWhen the user passes, Rupt redirects there with the evaluation ID appended:\n\n```\nhttps:\u002F\u002Fyourapp.com\u002Flogin\u002Fcomplete?evaluation=68f…\n```\n\n## Step 4: Consume the evaluation and start the session\n\nYour `\u002Flogin\u002Fcomplete` route takes the evaluation ID from the URL and **consumes** it. Consuming is a single-use, atomic claim: Rupt marks the evaluation spent and returns it in one step, so the same success URL can never start a second session. The first call wins; a replay throws `409`. Start the session only if the consume succeeds, the challenge completed, and the evaluation is still fresh.\n\n```ts\n\u002F\u002F POST \u002Flogin\u002Fcomplete\nconst { evaluation_id } = req.body;\n\nlet evaluation;\ntry {\n  \u002F\u002F Single-use: the first call wins, a replay throws 409.\n  evaluation = await rupt.consumeEvaluation(evaluation_id);\n} catch (err) {\n  if (err.status === 409) return reject(\"This login link was already used\");\n  \u002F\u002F Network or 5xx — fail open, allow the login to proceed. Worth logging.\n  return { session: startSession(evaluation.user) };\n}\n\nif (evaluation.action !== \"login\") return reject(\"Action mismatch\");\n\n\u002F\u002F Cap time on challenge to 10 mins (as an example).\nif (Date.now() - new Date(evaluation.createdAt).getTime() >= 10 * 60 * 1000) {\n  return reject(\"Login session expired\");\n}\n\nif (evaluation.challenge?.status !== \"completed\") {\n  return reject(\"Challenge not completed\");\n}\n\nreturn { session: startSession(evaluation.user) };\n```\n\nThe session starts here, never at `\u002Flogin` when a challenge was issued. Consuming rather than just reading is what makes it safe: an attacker who captures the success URL — or guesses an `evaluation_id` — finds it already spent, never completed, or expired.\n\n---\n\nPair this with [Signup protection](\u002Fdocs\u002Fv3\u002Ffundamentals\u002Fsignup-protection) and you've covered both ends of authentication. Every other guide builds on one of the two.\n",{"title":31,"description":1603},"zP1FXCvSfCb81qEAwFsRnjoveF1eF5-PzInmXSVOkDg",1780344892850]