Method, apparatus, and program for preventing content from leaking out

An apparatus for preventing a content leak, the apparatus comprising:

• a memory for storing instructions;
• and
• a processor having a plurality of functional units for executing the instructions stored in the memory, the functional units including:
• a view request receiving unit for receiving a content view request for viewing target content having a series of cuts, and obtaining content viewer information;
• a marker form determining unit for determining a marker form defining marking locations respectively corresponding to characters, according to the target content;
• a marking method determining unit for determining a marking method regarding a shape and size of markers to be added to the target content;
• and
• a modified content generating unit for generating a marking character string based on the content viewer information, and generating modified content by adding, in sequence, the marker to one cut of at least some of the series of cuts of the target content at the marking location corresponding to one character of the marking character string, based on the marker form and the marking method.