International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Content Extraction Signatures

Ron Steinfeld
Laurence Bull
Yuliang Zheng
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Abstract: Motivated by emerging needs in online interactions, we define a new type of digital signature called a `Content Extraction Signature' (CES). A CES allows the owner, Bob, of a document signed by Alice, to produce an `extracted signature' on selected extracted portions of the original document, which can be verified to originate from Alice by any third party Cathy, while hiding the unextracted (removed) document portions. The new signature therefore achieves verifiable content extraction with minimal multi-party interaction. We specify desirable functional and security requirements for a CES (including an efficiency requirement: a CES should be more efficient in either computation or communication than the simple multiple signature solution). We propose and analyze four CES constructions which are provably secure with respect to known cryptographic assumptions and compare their performance characteristics.
  title={Content Extraction Signatures},
  booktitle={IACR Eprint archive},
  keywords={public-key cryptography / digital signatures, privacy, content extraction},
  note={Earlier version was published at ICISC 2001. 11726 received 8 Feb 2002},
  author={Ron Steinfeld and Laurence Bull and Yuliang Zheng},