浅析 天涯论坛 回复验证策略

jQuery(function() {
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        for (E[F >> 5] |= 128 << F % 32, E[(F + 64 >>> 9 << 4) + 14] = F, G = 1732584193, H = -271733879, I = -1732584194, J = 271733878, l = 0; l < E.length; l += 16) {
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        }
        return Array(G, H, I, J)
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    function u(D, E, l, n, B, C) {
        return A(q(A(A(E, D), A(n, C)), B), l)
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    function w(C, D, E, F, l, n, B) {
        return u(D & E | ~D & F, C, D, l, n, B)
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    function x(C, D, E, F, l, n, B) {
        return u(D & F | E & ~F, C, D, l, n, B)
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    function y(C, D, E, F, l, n, B) {
        return u(D ^ E ^ F, C, D, l, n, B)
    }

    function z(C, D, E, F, l, n, B) {
        return u(E ^ (D | ~F), C, D, l, n, B)
    }

    function A(B, C) {
        var l = (65535 & B) + (65535 & C),
            n = (B >> 16) + (C >> 16) + (l >> 16);
        return n << 16 | 65535 & l
    }

    function q(l, n) {
        return l << n | l >>> 32 - n
    }
    var j, a = [],
        b = 0,
        c = 0,
        d = 2,
        e = 0,
        f = 20,
        g = "#textAreaContainer,#sendMsg_content,#msg_textarea",
        h = "user_action";
    jQuery(document).delegate(g, "blur", i).delegate(g, "keydown", i).delegate(g, "keypress", i).delegate(g, "keyup", i).delegate(g, "focus", i), j = 0
});

var j, a = [],
    b = 0,
    c = 0,
    d = 2,
    e = 0,
    f = 20, // 以上是一些初始化
    g = "#textAreaContainer,#sendMsg_content,#msg_textarea", // 输入区域
    h = "user_action"; // 最终验证值放在ID为 user_action 的元素里
jQuery(document).delegate(g, "blur", i).delegate(g, "keydown", i).delegate(g, "keypress", i).delegate(g, "keyup", i).delegate(g, "focus", i), j = 0;
// 监听 g 变量里的元素，当 聚焦，失去焦点，键盘按下，抬起，按键 都会触发 i 函数。那详细的分析下 i 都做了些什么吧。
function i(B) {
    var D, l, n, C = document.cookie.substr(document.cookie.indexOf("&id=") + "&id=".length);
    C = C.substr(0, C.indexOf("&")), C = "" == C ? 8980291 : C, D = jQuery(B.target), l = (new Date).getTime(), n = "focusout" == B.type ? "blur" : "focusin" == B.type ? "focus" : B.type, n = n.replace("key", "").substring(0, 1), 0 == c && (c = l), d >= f && (d = 2), a["c" == n ? 1 : "f" == n ? 0 : d++] = n + e+++"." + ("c" == n ? B.pageX + ":" + B.pageY : "b" == n ? d : "f" == n ? c : B.which) + "." + (l - ("c" == n || "f" == n ? c : b)), b = l, ("b" == n || 17 == B.which) && (v = a.join(",") + "|" + k(a.join(",") + a[0] + C) + "|" + k(D.val() + a[0]) + "|" + navigator.userAgent + "|v2", 0 == jQuery("#" + h).length ? jQuery(‘<input type="hidden" id="‘ + h + ‘" name="action" value="‘ + v + ‘" />‘).insertAfter(D) : jQuery("#" + h).val(v))
}

function i(B) {
    var D,
        l,
        n,
        C = document.cookie.substr(document.cookie.indexOf("&id=") + "&id=".length); // 为了取 cookies id 部分。。
    
    C = C.substr(0, C.indexOf("&")), // 取ID值
    C = "" == C ? 8980291 : C, // 如果没有，就用 8980291
    // 看他取个ID都这么纠结，应该是个新手写的。。。
    
    D = jQuery(B.target), // 当前元素
    l = (new Date).getTime(), // 当前时间戳，用于计算每步操作时间差
    n = "focusout" == B.type ? "blur" : "focusin" == B.type ? "focus" : B.type, // 修正事件名
    n = n.replace("key", "").substring(0, 1), // 取事件名第一个字符 f, b, d, p, u 分别对应 focus, blur, keydown, keypress, keyup
    0 == c && (c = l), // 上一次操作的时间戳，如果第一次操作，就用变量l的值。
    d >= f && (d = 2), // d 是数组下标，范围是 2-20。下标 0, 1 固定值特殊处理
    
    a["c" == n ? 1 : "f" == n ? 0 : d++] = n + e+++"." + ("c" == n ? B.pageX + ":" + B.pageY : "b" == n ? d : "f" == n ? c : B.which) + "." + (l - ("c" == n || "f" == n ? c : b)),
    // 这一行代码就验证重点，一个长度为 20 的数组，保存着获得焦点的时间戳和每个按键的记录
    // a[0] 格式固定："f" + 操作次数 + "." + 当前操作时间戳 + 与上次操作的时间间隔
    // a[0] 的数据类似这样：f2.1400154199651.2678
    // a[1] 忽略，直接空着即可，我也不知道 c 是什么事件，反正这个用不到。
    // a[2] - a[19] 格式类似，前缀不同。d, p, u 为一组占用3个元素，
    // 例如：[d8.97.167, p8.97.1, u8.97.75] 表示第 8 次操作，按键码是97，d 是 keydown与上次按下间隔167ms，p 是 keypress操作与按下间隔97ms，u 是 keyup与keypress间隔75ms
    // 这样循环填充数组，比如大于20，会重新从2开始，3个值一组的往后填充
    // 最后一个格式固定："b" + 操作次数 + "." + 数组循环到几（2-20之间的值） + "." + 与上次操作间隔。
    // 最后一个的数据类似这样：b12.14.862
    
    b = l, // 保存本次操作的时间戳
    if ("b" == n || 17 == B.which) { // 如果是失去焦点或者按了 ctrl(电脑上17是ctrl，手机端不知道是不是这个健)
        v = a.join(",") + "|" + k(a.join(",") + a[0] + C) + "|" + k(D.val() + a[0]) + "|" + navigator.userAgent + "|v2",
        // a 数组以 "," 拼接字符串
        // k 应该是 md5 之类的，没具体测试
        // 相当于 a数组 + "|" + md5(a数组 + 数组第一个元素 + 用户ID) + "|" + md5(用户输入的内容 + 数组第一个元素) + "|" + 浏览器信息 + "|v2"
        if (0 == jQuery("#" + h).length) { // 如果不存在 id="user_action" 的元素，就创建并插入到输入框后面
            jQuery(‘<input type="hidden" id="‘ + h + ‘" name="action" value="‘ + v + ‘" />‘).insertAfter(D)
        } else { // 如果操作就直接更新内容
            jQuery("#" + h).val(v)
        }
    }
}

f8.1400154504548.1565,,d8.97.167,p8.97.1,u8.97.75,d9.117.143,p9.117.4,u9.117.22,b10.8.2283,p4.114.3,u4.114.53,d5.116.122,p5.116.3,u5.116.2,d6.122.136,p6.122.5,u6.122.98,d7.105.49,p7.105.4,u7.105.79|094175120fb2ae4d5977afbe3fc04447|9de7848b9e445ba83c030b90651347fc|Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1847.131 Safari/537.36|v2