Stronger Security for Sanitizable Signatures
Sanitizable signature schemes $$\mathcal {SSS}$$SSS enable a designated party called the sanitizer to alter admissible blocks of a signed message. This primitive can be used to remove or alter sensitive data from already signed messages without involvement of the original signer. 
 
Current state-of-the-art security definitions of $$\mathcal {SSS}$$SSSs only define a "weak" form of security. Namely, the unforgeability, accountability and transparency definitions are not strong enough to be meaningful in certain use-cases. We identify some of these use-cases, close this gap by introducing stronger definitions, and show how to alter an existing construction to meet our desired security level. Moreover, we clarify a small yet important detail in the state-of-the-art privacy definition. Our work allows to deploy this primitive in more and different scenarios.