Epoch root
The single Merkle root summarizing every block hash in an epoch; it is the exact value written on-chain (the Stellar transaction memo hash or the Bitcoin OP_RETURN payload) and the root each proof bundle commitment's epoch proof (ep) 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 memo (Stellar) or op (Bitcoin) value, and the entry’s epoch proof (ep) is the inclusion proof that walks the block hash up to exactly that root; the field layout is in the proof bundle wire format.