Data URL scheme 笔记

Posted 2020-10-08 木剑配酒

0x01起因

　　今天做CTF的时候，发现一堆数据，大概是这样的

data:image/jpg;base64,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

　　刚开始，并不知道什么东西，唯一能看懂的是最后又两个==，还有base64，确定这些事base64编码。

　　百度发现这是RFC2397协议。

0x02结果

　　Data URL scheme定义了一种新的URL数据方案。因为有些应用程序需要将一些小型的媒体数据类型直接嵌入到网页中，减少请求资源的链接数。浏览器接收到数据后解码并渲染形成图片。

　　格式：data:[<mediatype>][;base64],<data>

　　　　mediatype是数据的类型，分为类型和子类型。

　　　　base64是支持的编码模式

　　　　逗号后面嵌入的数据。

　　　Data URL scheme 支持的格式：

data:,文本数据  
data:text/plain,文本数据  
data:text/html,HTML代码  
data:text/html;base64,base64编码的HTML代码  
data:text/css,CSS代码  
data:text/css;base64,base64编码的CSS代码  
data:text/javascript,Javascript代码  
data:text/javascript;base64,base64编码的Javascript代码  
data:image/gif;base64,base64编码的gif图片数据  
data:image/png;base64,base64编码的png图片数据  
data:image/jpeg;base64,base64编码的jpeg图片数据  
data:image/x-icon;base64,base64编码的icon图片数据