1. A signature device of a validation system, the signature device comprising: a processor comprising: a dividing unit to divide content into a plurality of segments; a hash unit to calculate an initial hash value by hashing the content before the content is divided and to calculate a hash value of each of the plurality of segments; a content hash generating unit to generate a content hash value by performing an exclusive or (XOR) operation with respect to the hash values of the plurality of segments and the initial hash value; a signature unit to sign the content hash value with a signature key to generate a signature value; a verification information generating unit to generate verification information for each of the segments by performing an XOR operation with respect to the content hash value with each of the hash values of the plurality of segments; and a packet generating unit to generate a packet for each of the plurality of segments, each packet including a corresponding segment, verification information associated with the corresponding segment, and the signature value.