请教一下验证码的实现原理
请问一下验证码的实现原理
验证码是很有必要的，可为什么像百度贴吧那些的，它的验证码上面要弄些斑斑点点的来干扰视觉辨认呢？我觉得不用干扰也可以的呀。
还有就是请问验证码的实现及应用原理是什么？有人可以简要的说明一下吗？谢谢
我的感觉是用验证码应该要用的html里的hidden元素，不知对否？
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不干扰一下，别人很轻易使用orc识别技术伪装获取你的验证码的，这样他们就轻易制作信息发布机器人了
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填写界面显示随机数让用户填写到表单，且这个随机数写入SESSION，提交后处理代码判断用户有没有这个提交随机数且和session中的值比较，然后....
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可这个服务器端怎么知道$_SESSION[ 'verify ']这个session变量是属于哪个客户端浏览器的呢？
答: 每个浏览客户端都会和服务器建立一个唯一的SESSION
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