Object attribute-based watermarking method for preventing leakage of digital content

A video streaming server system comprising:

• a processor comprising:
• a communication unit configured to receive a request for video streaming of a video from a user, and to stream the requested video;
• and
• a Database (DB) configured to store videos and watermarking information;
• and
• the processor configured to:
• acquire the requested video and watermarking information from the DB;
• identify, by analyzing frame-wise metadata of the video, determine one or more background objects corresponding to a watermarking rule defined for a user-specific code;
• select, from among a plurality of visual attributes of each identified background object, at least one attribute including a color, texture, or brightness value designated by the watermarking rule;
• transform the selected attribute according to the watermarking information by adjusting pixel values belonging to the background object such that a visual appearance of the video remains substantially unchanged but the transformation can be detected through comparison with original attribute parameters;
• and
• stream the transformed video through the communication unit.

A method for tracing a video leakage path, the method comprising:

• acquiring watermarking information of a leaked video;
• identifying, from the leaked video, at least one background object whose pixel values have been changed according to a watermarking rule associated with a user-specific code that determined the identified at least one background object by analyzing frame-wise metadata of the leaked video;
• comparing attribute parameters of the identified background object with corresponding original attribute parameters stored in association with the watermarking information to infer a user-specific code from the result of determining;
• and
• acquiring a user ID by decoding the inferred user-specific code.