Method and apparatus for generating content identifier and preventing alteration of the content identifier

A method of determining alteration of a content identifier, the method comprising:

• receiving a content;
• receiving a content identifier comprising:
• a first integrity verification value for a plurality of parts of the content, and
• at least one random number;
• extracting the first integrity verification value and the at least one random number from the content identifier;
• generating location information for designating a plurality of locations within the content using the at least one random number;
• extracting a plurality of parts of the content, which correspond to the location information;
• generating a second integrity verification value according to a method used for generating the first integrity verification value based on the plurality of parts of the content;
• and
• determining whether the content identifier is altered by comparing the first integrity verification value with the second integrity verification value.

A content identifier generating apparatus for preventing alteration of the content identifier, the apparatus comprising:

• a random number generating unit which generates at least one random number;
• a location information generating unit which generates location information, wherein the location information designates a plurality of locations within a content by using the at least one random number;
• an extracting unit which extracts a plurality of parts of the content corresponding to the location information;
• an integrity verification value generating unit which generates an integrity verification value based on the plurality of parts of the content;
• and
• an identifier generating unit which generates the content identifier, wherein the content identifier comprises:
• the integrity verification value, and
• the at least one random number.

An apparatus for determining alteration of a content identifier, the apparatus comprising:

• a receiving unit which receives a content and a content identifier comprising:
• a first integrity verification value for a plurality of parts of the content, and
• at least one random number;
• an extracting unit which extracts the first integrity verification value and the at least one random number from the content identifier;
• a location information generating unit which generates location information, wherein the location information designates a plurality of locations within the content by using the at least one random number;
• an integrity verification value generating unit which generates a second integrity verification value according to a method used for generating the first integrity verification value based on an extracted parts of the content, wherein the extracted parts of the content correspond to the location information and are extracted by the extracting unit;
• and
• a determining unit which determines whether the received content identifier is altered by comparing the first integrity verification value with the second integrity verification value.