Data Availability Certificates (DACerts)

At the core of AnyTrust lies the concept of the Data Availability Certificate (DACert). This certificate comprises the hash of a data block, an expiration time, and evidence that N-1 Committee members have signed the (hash, expiration time) pair. This evidence includes the hash of the Keyset used for signing, a bitmap indicating the signing Committee members, and a BLS aggregated signature over the BLS12-381 curve, affirming the authenticity of the signatures.

Operating on the 2-of-N trust assumption, a DACert provides assurance that a block's data will be accessible from at least one honest Committee member until the specified expiration time. This foundational trust assumption forms the basis for the reliability and security of data availability within the AnyTrust framework.