Essentials of Data Availability Certificates (DACerts)

At the heart of the AnyTrust architecture lies the Data Availability Certificate (DACert), a pivotal element. A DACert consists of a data block's hash, an assigned expiration time, and a confirmation that N-1 Committee members have endorsed the (hash, expiration time) combination. This endorsement is substantiated through the hash of the utilized Keyset for the signing, a bitmap showcasing the signatory Committee members, and a collective BLS signature using the BLS12-381 curve as a testament to the signatures.

Given the foundational 2-of-N trust model, a DACert acts as a guarantee of the data block’s availability, vouched by at least one upright Committee member until the designated expiration time. This model is crucial for ensuring the trustworthiness and security of data availability within the AnyTrust framework.