Accountable redactable signatures

Abstract

Redact able signature schemes (RSS) allow removing blocks from signed data. State-of-the-art schemes have public redactions, i.e., Any party can remove parts from a signed message. This prohibits meaningful definitions of accountability. We address this gap by introducing the notion of accountable redact able signature schemes (ARSS). We present a generic construction which couples a sanitizable signature scheme (SSS) to profit from its accountability with an RSS to maintain the reduced malleability of RSSs. Depending on the building blocks, the resulting scheme offers transparency or public accountability. Transparency provides stronger privacy guarantees, while public accountability meets legal and application requirements.