結合硬體與軟體的光碟防盜拷技術

Abstract

我們提出同時使用硬體與軟體的光碟防盜拷技術。在我們的方法中，半準位訊號x-bit提供人為錯誤置於光碟片中，再利用多階的MWE程序來編碼原始鑰匙。由於多階的編碼程序導致一個非常特殊的解碼效能，會產生一個近似方波的原始鑰匙解碼正確機率，而這個特性可以用來防制盜拷。更進一步，我們提出新的編碼方法來增加盜拷光碟的困難度，並有效降低編碼所需的容量。

We propose a hybrid hardware/software copy protection technique based on the X-bit coding and a multi-level word-extension /error-coding (MWE) scheme to encode an encryption key. The X-bits with half-level signaling behave as potential errors in optical disk. The multi-level coding leads to a very special decoding performance that a sharp cutoff exists in the detection probability of the encryption key. This cutoff behavior sets a tight bound on the signal level of X-bits, being the desired characteristic for us to prevent piracy. Finally，we propose a modified approach to decrease the tight bound on the signal level of X-bits as well as volume of the encryption key.