With the development of HD video, the protection of copyright becomes more complicated. More advanced copyright protection technology is needed. Traditional digital copyright protection technology generally uses direct or selective encryption algorithm and the key does not associate with the video content<sup> . </sup>Once the encryption method is cracked or the key is stolen, the copyright of the video will be violated. To address this issue, this paper proposes a Sensitive Data Extraction Algorithm (SDEA) based on the content associated encryption technology which applies to the Internet Certification Service (ICS). The principle of content associated encryption is to extract some data from the video and use this extracted data as the key to encrypt the rest data. The extracted part from video is called sensitive data, and the rest part is called the main data. After extraction, the main data will not be played or poorly played. The encrypted sensitive data reach the terminal device through the safety certificated network and the main data are through ICS disc. The terminal equipments are responsible for synthesizing and playing these two parts of data. Consequently, even if the main data on disc is illegally obtained, the video cannot be played normally due to the lack of necessary sensitive data. It is proved by experiments that ICS using SDEA can destruct the video effectively with 0.25% extraction rates and the destructed video cannot be played well. It can also guarantee the consistency of the destructive effect on different videos with different contents. The sensitive data can be transported smoothly under the home Internet bandwidth.