International Association
for Cryptologic Research

Cryptography is generally used to protect sensitive data from an untrusted server. In this paper, we investigate the converse question: can we use cryptography to protect a trusted server from untrusted data?

As a first step in this direction, we propose the notion of safe enclosures. Intuitively, a safe enclosure is a cryptographic primitive that encapsulates data in a way that allows to perform some computation on it, while at the same time protecting the server from malicious data. Furthermore, a safe enclosure should come equipped with a dedicated protocol that implements the enclosing function with unconditional integrity. Otherwise, unguarded data may reach the server. We discuss the novelty of these concepts, propose their formal definition and show several realizations.