A Sanitizing Signature Scheme with Indexing

A sanitizing signature scheme, which is a variant of digital signatures, enables a trusted party named sanitizer to modify parts of signed documents without corresponding to the signer. A lot of sanitizing signature schemes have been proposed since 2001. However these schemes are suitable for table-style documents, but none of them are considered for story-style documents. We consider that the solution to this problem is adding index to the sanitized document in the signing phase. Thus, a verifier can verify the validity of the document and understand the story in the help of the indexes, even though some messages have been masked. In this paper, we propose a new sanitizing signature scheme with indexing that realizes index-based verification and holds its privacy.