{"id":391,"date":"2025-03-07T00:27:47","date_gmt":"2025-03-07T03:27:47","guid":{"rendered":"https:\/\/www.wagnersalvi.com.br\/?p=391"},"modified":"2025-03-07T00:40:37","modified_gmt":"2025-03-07T03:40:37","slug":"validacao-de-numero-de-cartao-de-credito","status":"publish","type":"post","link":"http:\/\/www.wagnersalvi.com.br\/?p=391","title":{"rendered":"Valida\u00e7\u00e3o de N\u00famero de Cart\u00e3o de Cr\u00e9dito"},"content":{"rendered":"\n

A valida\u00e7\u00e3o do n\u00famero de um cart\u00e3o de cr\u00e9dito geralmente \u00e9 feita usando o Algoritmo de Luhn. Esse algoritmo \u00e9 um m\u00e9todo de verifica\u00e7\u00e3o simples para detectar erros de digita\u00e7\u00e3o em n\u00fameros de cart\u00f5es.<\/p>\n\n\n\n

O Algoritmo de Luhn<\/strong> \u00e9 um m\u00e9todo de verifica\u00e7\u00e3o de soma de verifica\u00e7\u00e3o (checksum) usado para validar n\u00fameros de identifica\u00e7\u00e3o, como cart\u00f5es de cr\u00e9dito, IMEI de celulares e outros n\u00fameros sequenciais. Foi inventado por Hans Peter Luhn<\/strong>, um cientista da IBM, em 1954.<\/p>\n\n\n\n

Passos do Algoritmo de Luhn<\/strong><\/h5>\n\n\n\n
    \n
  1. Remova espa\u00e7os e caracteres n\u00e3o num\u00e9ricos<\/strong> do n\u00famero do cart\u00e3o.<\/li>\n\n\n\n
  2. Comece da direita para a esquerda<\/strong>:\n
      \n
    • Dobre o valor de cada segundo d\u00edgito.<\/li>\n\n\n\n
    • Se o resultado da multiplica\u00e7\u00e3o for maior que 9, some os d\u00edgitos do resultado (exemplo: 8\u00d72=16\u21d21+6=7).<\/li>\n\n\n\n
    • Some todos os n\u00fameros (os dobrados e os n\u00e3o dobrados).<\/li>\n<\/ul>\n<\/li>\n\n\n\n
    • Verifique se a soma total \u00e9 m\u00faltiplo de 10<\/strong>.\n
        \n
      • Se for, o n\u00famero \u00e9 v\u00e1lido.<\/li>\n\n\n\n
      • Caso contr\u00e1rio, \u00e9 inv\u00e1lido.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n
        Exemplo de Valida\u00e7\u00e3o<\/strong><\/h5>\n\n\n\n

        Suponha que o n\u00famero do cart\u00e3o seja “4539 1488 0343 6467”<\/strong>.<\/p>\n\n\n\n

        Remover espa\u00e7os<\/strong>: 4539148803436467<\/code><\/p>\n\n\n\n

        Separar d\u00edgitos e dobrar os alternados<\/strong>:<\/p>\n\n\n\n

        N\u00famero original:  4 5 3 9 1 4 8 8 0 3 4 3 6 4 6 7
        Dobrar os pares:  8 5 6 9 2 4 16 8 0 3 8 3 12 4 12 7<\/pre>\n\n\n\n
        Somar os d\u00edgitos<\/strong>:<\/p>\n\n\n\n
          \n
        • Para n\u00fameros com dois d\u00edgitos, somamos os algarismos (ou subtraia 9 deste valor que gera o mesmo resultado:<\/li>\n<\/ul>\n\n\n\n
          16 \u2192 1+6 = 7<\/code>, 12 \u2192 1+2 = 3<\/code>, 12 \u2192 1+2 = 3<\/code>  ou
          16 \u2192 16-9 = 7<\/code>, 12 \u2192 12-9 = 3<\/code>, 12 \u2192 12-9 = 3<\/code><\/pre>\n\n\n\n
            \n
          • Soma total:<\/li>\n<\/ul>\n\n\n\n
            (8 + 5 + 6 + 9 + 2 + 4 + 7 + 8 + 0 + 3 + 8 + 3 + 3 + 4 + 3 + 7) = 70<\/pre>\n\n\n\n
            Divis\u00edvel por 10?<\/strong><\/p>\n\n\n\n
            70 % 10 == 0<\/code> -> N\u00famero v\u00e1lido!<\/strong><\/p>\n\n\n\n
            Aqui est\u00e1 um c\u00f3digo para validar um n\u00famero de cart\u00e3o usando o Algoritmo de Luhn:<\/p>\n\n\n\n
            using System;\nusing System.Linq;\n\nclass Program\n{\n    static void Main()\n    {\n        Console.Write(\"Digite o n\u00famero do cart\u00e3o: \");\n        string numeroCartao = Console.ReadLine().Replace(\" \", \"\").Replace(\"-\", \"\");\n\n        if (EhValidoLuhn(numeroCartao))\n            Console.WriteLine(\"Cart\u00e3o v\u00e1lido!\");\n        else\n            Console.WriteLine(\"Cart\u00e3o inv\u00e1lido.\");\n    }\n\n    static bool EhValidoLuhn(string numero)\n    {\n        if (!numero.All(char.IsDigit)) return false;\n\n        int soma = 0;\n        bool dobrar = false;\n\n        for (int i = numero.Length - 1; i >= 0; i--)\n        {\n            int digito = numero[i] - '0';\n\n            if (dobrar)\n            {\n                digito *= 2;\n                if (digito > 9) digito -= 9;\n            }\n\n            soma += digito;\n            dobrar = !dobrar;\n        }\n\n        return soma % 10 == 0;\n    }\n}<\/pre>\n
            Views: 0<\/p>","protected":false},"excerpt":{"rendered":"
            A valida\u00e7\u00e3o do n\u00famero de um cart\u00e3o de cr\u00e9dito geralmente \u00e9 feita usando o Algoritmo de Luhn. Esse algoritmo \u00e9 […]<\/p>\n","protected":false},"author":1,"featured_media":392,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[49],"tags":[202,62,201,43],"class_list":["post-391","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-programacao","tag-algoritmo","tag-c","tag-luhn","tag-programacao"],"_links":{"self":[{"href":"http:\/\/www.wagnersalvi.com.br\/index.php?rest_route=\/wp\/v2\/posts\/391","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.wagnersalvi.com.br\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.wagnersalvi.com.br\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.wagnersalvi.com.br\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.wagnersalvi.com.br\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=391"}],"version-history":[{"count":0,"href":"http:\/\/www.wagnersalvi.com.br\/index.php?rest_route=\/wp\/v2\/posts\/391\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.wagnersalvi.com.br\/index.php?rest_route=\/wp\/v2\/media\/392"}],"wp:attachment":[{"href":"http:\/\/www.wagnersalvi.com.br\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=391"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.wagnersalvi.com.br\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=391"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.wagnersalvi.com.br\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=391"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}