From @Mithgol on Mon Sep 14 2015 14:27:32 GMT+0000 (UTC) A Merkle DAG is a Merkle directed acyclic graph. That is a data structure similar to a Merkle tree but not so strict: such DAG does not need to be balanced and its non-leaf nodes are allowed to contain data.
Copied from original issue: https://github.com/ipfs/faq/issues/31
From @jbenet on Mon Sep 14 2015 14:31:44 GMT+0000 (UTC) Correct!
From @Mithgol on Mon Sep 14 2015 14:40:53 GMT+0000 (UTC) And a hyperlink to the spec of the IPFS Merkle DAG for future references.
That link 404’s now. Here’s the spec as of today:
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# !(https://img.shields.io/badge/status-deprecated-red.svg?style=flat-square) The merkledag
**This spec has been deprecated in favor of [IPLD](https://github.com/ipld/specs/).** It offers a clearer description of how to link different kinds of hash-based structures (e.g. linking a file in IPFS to a commit in Git), has a more generalized and flexible format, and uses a JSON-compatible representation, among other improvements.
- [Juan Benet](https://github.com/jbenet)
- [Jeromy Johnson](https://github.com/whyrusleeping)
* * *
The _ipfs merkledag_ is a directed acyclic graph whose edges are merkle-links. This means that links to objects can authenticate the objects themselves, and that every object contains a secure representation of its children.
This is a powerful primitive for distributed systems computations. The merkledag simplifies distributed protocols by providing an append-only authenticated datastructure. Parties can communicate and exchange secure references (merkle-links) to objects. The references are enough to verify the correctness of the object at a later time, which allows the objects themselves to be served over untrusted channels. Merkledags also allow the branching of a datastructure and subsequent merging, as in the version control system git. More generally, merkledags simplify the construction of Secure [CRDTs](http://en.wikipedia.org/wiki/Conflict-free_replicated_data_type), which enable distributed, convergent, commutative computation in an authenticated, secure way.
## Table of Contents
Note: The Merkle DAG has been deprecated in favor of IPLD