Análise de Vulnerabilidade de Esquemas de Segredo Compartilhado Considerando um novo Modelo de Ameaça
Abstract
Secret sharing schemes are cryptographic primitives used to distribute parts of a secret among a set of participants in such a way that only an authorized subset can rebuild the secret. Traditionally, most secret sharing schemes work with only two entity definitions: The Dealer and Participants. For these schemes, several threat models have been proposed considering only these two entities. However, in the literature it is not clear who should play the role of rebuilding the secret and who would be the keeper of the secret. These two new entities modify the existing threat models that consider: (i) the distributor initializes the system and splits and shares the secret, and (ii) the participants cooperate or not with the secret reconstruction. In this work we propose a new threat model considering the new entities that represent the roles involved in shared secret schemes. Considering this new model, we show that some of the best-known schemes are vulnerable. We make evaluations checking which points can be safely maintained and at which points vulnerabilities will emerge according to the new entities and new threat model.
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