COSE Receipts for MMRs

This document defines a new verifiable data structure type for COSE Receipts [I-D.ietf-cose-merkle-tree-proofs] specifically for use with ledgers based on post-order traversal binary Merkle trees and which are designed for high throughput, ease of replication and compatibility with commodity cloud storage. Post-order traversal binary Merkle trees, also known as history trees, are more commonly known as Merkle Mountain Ranges.