Active quotation authentication in Microsoft Word documents using block signatures

Traditional message authentication does not verify the integrity and the claimed source of quotations in an anonymous message. A new active quotation authentication framework is proposed that allows a reader to authenticate the content and origin of the quotations in a citing document. A block signature method is proposed that generates context-sensitive block signatures for an authoritative message, and allows quotation signatures to be generated on-the-fly for arbitrary sub passages by an anonymous author. The block signature method requires a small initial computational effort and storage requirement for block signature generation; has a small quotation signature overhead; and is efficient for quotation authentication.