中文摘要：

数字指纹技术是一种可以追踪到非法拷贝源的数字版权保护技术，其中一种潜在的威胁就是几个合法用户共谋攻击。针对已有的抗合谋扩频正交数字指纹方案支持用户数较少的缺点，提出了一种关于扩频正交数字指纹码的扩展方案，从理论和实验上证明该方案提高了系统所能支持的用户数，并且保持了原方案较好的抗合谋性能。

英文摘要：

Digital fingerprinting is a digital copyright protection technology used to track the source of illegal redistributors. But the collusion attack of several legal users is a potential threat. For the weakness of supporting fewer users in the original anti-collusion spread spectrum orthogonal digital fingerprinting scheme, a scalable spread spectrum orthogonal digital fingerprinting scheme is proposed. It is proved that this scheme increases the number of users the system supports and maintains the original scheme’s better performance against collusion from theoretical analysis and experiments.