Epoch root
The single Merkle root summarizing every block hash in an epoch, the exact value written on-chain as a Stellar transaction memo hash or a Bitcoin OP_RETURN payload, carried in a proof bundle as each commitment's epoch_merkle_root and the root its epoch_proof walks a block hash up to.
Overview
The epoch root is the single Merkle root summarizing all the block hashes in an epoch: Truestamp batches many finalized block hashes into one Merkle tree and records only that one root value on a public blockchain, as described in the epoch and Block Commitment. On Stellar the epoch root is written as the transaction’s memo hash; on Bitcoin it is written as OP_RETURN data. In a proof bundle the epoch root appears as each commitment entry’s epoch_merkle_root, one key on both chains rather than a per-chain spelling, and the entry’s epoch_proof is the inclusion proof that walks the block hash up to exactly that root; the field layout is in the proof bundle wire format.