HTML与Python生成验证码的对比分析

前言

验证码（CAPTCHA）是确保用户行为为人类而非机器人自动执行的一种安全机制。通过图形、文字、或其他手段生成复杂的验证码来防止自动化攻击是一种常见的方法。本文将对比分析使用HTML与JavaScript和Python生成验证码的两种方式，探讨各自的优劣之处。

HTML与JavaScript生成验证码

以下是用HTML与JavaScript生成验证码的代码示例：

    
    
    验证码示例
    
        #v_container {
            width: 200px;
            height: 50px;
            cursor: pointer;
        }
        #verifyCanvas {
            display: block;
        }
    


    

    
    验证
    
    (function(window, document) {
        function GVerify(options) {
            this.options = {
                id: options.id || "",
                canvasId: "verifyCanvas",
                width: options.width || "100",
                height: options.height || "30",
                type: options.type || "blend",
                code: "",
                numArr: "0,1,2,3,4,5,6,7,8,9".split(","),
                letterArr: getAllLetter()
            };
            this._init();
            this.refresh();
        }
        GVerify.prototype = {
            _init: function() {
                var con = document.getElementById(this.options.id);
                var canvas = document.createElement("canvas");
                this.options.width = con.offsetWidth || 100;
                this.options.height = con.offsetHeight || 30;
                canvas.id = this.options.canvasId;
                canvas.width = this.options.width;
                canvas.height = this.options.height;
                con.appendChild(canvas);
                var parent = this;
                canvas.onclick = function() {
                    parent.refresh();
                }
            },
            refresh: function() {
                this.options.code = "";
                var canvas = document.getElementById(this.options.canvasId);
                var ctx = canvas.getContext('2d');
                ctx.textBaseline = "middle";
                ctx.fillStyle = randomColor(180, 240);
                ctx.fillRect(0, 0, this.options.width, this.options.height);
                var txtArr = this.options.type === "blend" ? this.options.numArr.concat(this.options.letterArr)
                            : this.options.type === "number" ? this.options.numArr
                            : this.options.letterArr;
                for (var i = 1; i 
                    var txt = txtArr[randomNum(0, txtArr.length)];
                    this.options.code += txt;
                    ctx.font = randomNum(this.options.height / 2, this.options.height) + 'px SimHei';
                    ctx.fillStyle = randomColor(50, 160);
                    ctx.shadowOffsetX = randomNum(-3, 3);
                    ctx.shadowOffsetY = randomNum(-3, 3);
                    ctx.shadowBlur = randomNum(-3, 3);
                    ctx.shadowColor = "rgba(0, 0, 0, 0.3)";
                    var x = this.options.width / 5 * i;
                    var y = this.options.height / 2;
                    var deg = randomNum(-30, 30);
                    ctx.translate(x, y);
                    ctx.rotate(deg * Math.PI / 180);
                    ctx.fillText(txt, 0, 0);
                    ctx.rotate(-deg * Math.PI / 180);
                    ctx.translate(-x, -y);
                }
                for (var i = 0; i