Method and apparatus for verifying integrity of redacted documents

One embodiment of the present invention provides a system which allows a document owner to redact content from a document and allows a recipient of the redacted document to challenge the appropriateness of the redaction. During operation, the system allows the document owner to redact a string M i from location i in the document. In doing so, the system produces a commitment C ¡ = C ( M i , R i ) based on string M i and a string R i used as randomness and communicates C i to the recipient (204). When the recipient challenges (206) the redaction, the system receives a topic string T from the recipient, and produces a string R T . The system then communicates R T to the recipient (210), thereby allowing the recipient to produce a commitment C T = C ( T , R T ) based on strings T and R T , and compare C T with C i . Comparing commitment C T with C i allows the recipient to test redactions for string equality.