BetaLog

作者:zyqin http://www.betalog.cn

有一种技术可以把信息嵌入到其他信息中，而不会损害其他信息，这就是速记式加密。它通过替换电脑文件（例如图片、声音、文本、HTML或者是软盘）中的无用的或不用的字节，来隐藏信息。这些隐藏的信息可以使普通文本、密码文本或图像等。

速记式加密有时候会在不能使用算法加密时派上用场，或者，作为算法加密的补充形式。一个被加密的文件可能还被通过速记式加密方式隐藏着信息，所以即使被加密的文件被破解，被隐藏的信息还是不能被发现。

有些软件使用速记式加密，有许多好的网站提供这些免费版本的下载。

速记式加密(表面意思是覆写)，这个词可以追溯到古希腊，人们会把信息刻在木简上，然后打上蜡，在消息的前部分再刻上一些无用的信息，等信息送达目的地再将刻在蜡上的无用信息挂掉。

The art and science of hiding information by embedding messages within other, seemingly harmless messages. Steganography works by replacing bits of useless or unused data in regular computer files (such as graphics, sound, text, HTML, or even floppy disks ) with bits of different, invisible information. This hidden information can be plain text, cipher text, or even images.

Steganography sometimes is used when encryption is not permitted. Or, more commonly, steganography is used to supplement encryption. An encrypted file may still hide information using steganography, so even if the encrypted file is deciphered, the hidden message is not seen.

Special software is needed for steganography, and there are freeware versions available at any good download site.

Steganography (literally meaning covered writing) dates back to ancient Greece, where common practices consisted of etching messages in wooden tablets and covering them with wax, and tattooing a shaved messenger's head, letting his hair grow back, then shaving it again when he arrived at his contact point.