An apparatus for verifying integrity of an electronic book, e-book, the apparatus comprising: an e-book receiving unit configured to receive e-book data including e-book basis data (EB_BD), e-book usage rights data (EB_RD), e-book encryption data (EB_ED) and e-book e-signature data (EB_SD), and an e-book integrity verification unit configured to verify integrity of the e-book data received through the e-book receiving unit, and wherein the e-book basis data (EB_BD) includes title information of the e-book, wherein the e-book usage rights data (EB_RD) includes usage period information and legal user information of the e-book, wherein the e-book encryption data (EB_ED) includes information on encryption of the e-book, wherein the e-book e-signature data (EB_SD) includes e-signature information, an e-signature value, decryption key information and e-signature-object information, wherein the e-signature-object information includes a second digest value generated by applying a second hash function to the e-book encryption data (EB_ED), a third digest value generated by applying the second hash function to the e-book usage rights data (EB_RD) and a fourth digest value generated by applying a second hash function to the e-book basis data (EB_BD), wherein the e-signature information includes a first digest value generated by applying a first hash function to the e-signature-object information, wherein the e-signature value is generated by applying an encryption function employing a private key as an encryption key to the first digest value, wherein the e-book integrity verification unit verifies integrity of the e-book data by comparing a fifth digest value generated by applying the encryption function employing a public key corresponding to the private key as a decryption key to the e-signature value with the first digest value included in the e-signature information, and by comparing the first digest value with a sixth digest value generated by applying the first hash function to the e-signature object information, wherein the e-book integrity verification unit verifies the integrity of the e-book data by comparing a ninth digest value generated by applying the second hash function to the e-book basis data (EB_BD) with the fourth digest value included in the e-signature-object information, comparing an eighth digest value generated by applying the second hash function to the e-book usage rights (EB_RD) data with the third digest value included in the e-signature-object information, and comparing a seventh digest value generated by applying the second hash function to the e-book encryption data (EB_ED) with the second digest value included in the e-signature-object information. an e-book receiving unit configured to receive e-book data including e-book basis data (EB_BD), e-book usage rights data (EB_RD), e-book encryption data (EB_ED) and e-book e-signature data (EB_SD), and an e-book integrity verification unit configured to verify integrity of the e-book data received through the e-book receiving unit, and wherein the e-book basis data (EB_BD) includes title information of the e-book, wherein the e-book usage rights data (EB_RD) includes usage period information and legal user information of the e-book, wherein the e-book encryption data (EB_ED) includes information on encryption of the e-book, wherein the e-book e-signature data (EB_SD) includes e-signature information, an e-signature value, decryption key information and e-signature-object information, wherein the e-signature-object information includes a second digest value generated by applying a second hash function to the e-book encryption data (EB_ED), a third digest value generated by applying the second hash function to the e-book usage rights data (EB_RD) and a fourth digest value generated by applying a second hash function to the e-book basis data (EB_BD), wherein the e-signature information includes a first digest value generated by applying a first hash function to the e-signature-object information, wherein the e-signature value is generated by applying an encryption function employing a private key as an encryption key to the first digest value, wherein the e-book integrity verification unit verifies integrity of the e-book data by comparing a fifth digest value generated by applying the encryption function employing a public key corresponding to the private key as a decryption key to the e-signature value with the first digest value included in the e-signature information, and by comparing the first digest value with a sixth digest value generated by applying the first hash function to the e-signature object information, wherein the e-book integrity verification unit verifies the integrity of the e-book data by comparing a ninth digest value generated by applying the second hash function to the e-book basis data (EB_BD) with the fourth digest value included in the e-signature-object information, comparing an eighth digest value generated by applying the second hash function to the e-book usage rights (EB_RD) data with the third digest value included in the e-signature-object information, and comparing a seventh digest value generated by applying the second hash function to the e-book encryption data (EB_ED) with the second digest value included in the e-signature-object information.