Where is the incentive to update the Merkle root


The idea (as I understand it) is that the Merkle tree allows for you to verify transactions as needed and not include the body of every transaction in the block header, while still providing a way to verify the entire blockchain (and therefore proof of work) on every transaction.

To understand this, first understand the concept of a tree. Consider an 8 transaction block. Imagine each of those 8 transactions at the base of a pyramid: these are called leaves. Put four "branches" on the second tier of the pyramid and draw two lines from each of them to the leaves so that each branch has two leaves attached to it. Now join those four branches to two branches on pyramid level 3 and up to one branch (what is called the root of the tree) on the top of the pyramid. (Our tree is growing upside down in this example.)

Now we can start to understand the hashing process. Hash the hashes of the "leaves" and include that as part of the 2nd level branches that those leaves are...

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I'm currently attempting to implement a merkle-tree data structure in Go. Basically, my end goal is to store a small set of structured data (10MB max) and allow this "database" to be easily synchronised with other nodes distributed over the network (see related ). I've implemented this reasonably effectively in Node as there are no type-checks. Herein lies the problem with Go, I'd like to make use of Go's compile-time type checks, though I also want to have one library which works with any provided tree.

In short, I'd like to use structs as merkle nodes and I'd like to have one Merkle.Update() method which is embedded in all types. I'm trying to avoid writing an Update() for every struct (though I'm aware this might be the only/best way).

My idea was to use embedded types:

//library type Merkle struct { Initialised bool Container interface{} //in example this references foo Fields []reflect.Type //... other merkle state } //Merkle methods... Update()......
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What is the data availability problem?

One of the important challenges in making light client protocols and sharded blockchain protocols is the so-called "data availability problem".

In order to understand the data availability problem, it is best to first start off by understanding the concept of "fraud proofs". Suppose that an attacker makes a block which is invalid in some way (for example, the post-state root is wrong, or some transaction is invalid or mal-formatted). Then, it is possible to create a "fraud proof" that contains the transaction and some Merkle tree data from the state and use it to convince any light client, as well as the blockchain itself, that the block is invalid. Intuitively, one can think of this fraud proof as containing just the parts of the state required to process the block in question, plus some hashes to prove that the parts of the state provided actually do represent the state that the block claims to be building on top of....

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In cryptography and computer science, a hash tree or Merkle tree is a tree in which every non-leaf node is labelled with the hash of the labels of its children nodes. Hash trees are useful because they allow efficient and secure verification of the contents of large data structures. Hash trees are a generalization of hash lists and hash chains.

Demonstrating that a leaf node is a part of the given hash tree requires processing an amount of data proportional to the logarithm of the number of nodes of the tree; this contrasts with hash lists, where the amount is proportional to the number of nodes. The concept of hash trees is named after Ralph Merkle who patented it in 1979.

In the blochchain every transaction has a hash associated with it. In a block, all of the transaction hashes in the block are themselves hashed (sometimes several times, the exact process is complex), and the result is the Merkle root. In other words, the Merkle root is the hash of all the hashes...

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In Part 1 we took a look at the incentives involved in Bitcoin mining and how they are used guarantee a single transaction history needed to prevent bitcoins from being double spent. In this post we will take more a technical look at the cryptography involved and how it is used to secure the network. As I said previously, Bitcoin is very accessible. While we will be discussing cryptographic concepts, it shouldn’t discourage you from continuing further.

Cryptographic Hash Functions

Before moving forward we should take a moment to learn about hash functions since they are used all throughout the Bitcoin protocol. To put it simply, a hash function is just a mathematical algorithm that takes an input and turns it into an output. For example, suppose we have an algorithm which just adds all the digits in the input string together. If our input is 1234 we would get an output of 10.

1234 ==> 10

Simple enough. However, there are certain properties of really good hash...

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The Bitcoin network is only as strong as the number of miners and nodes supporting the protocol. At this time, there is no shortage of mining power pointed at the Bitcoin network, but the number of nodes remains fairly low in comparison. Some people feel more nodes would be active on the network if there were some reward for doing so. But isn’t being part of Bitcoin itself the biggest reward one can get for running a Bitcoin Node?

Also read: Blockchain.info Platform Issues Continue

Bitcoin Node Incentives Is A Touchy Subject

In the perfect world, Bitcoin nodes could end up receiving a reward similar to the small amounts of funds collected by Bitcoin miners for adding transactions to the next block on the network. However, the technology was never designed to operate in that regard, as running a network node is entirely voluntary and not subject to incentives.

Certain people might feel this form of distributing the transaction fees is not fair,...

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I will try to explain the relation between Segwit and AsicBoost, in both the covert and overt forms, in certain detail. I will also try to explain why a method was recently proposed to reduce the interference between covert-AsicBoost and some protocol improvements, by reducing the incentives for covert AsicBoost. The proposal makes covert AsicBoost more expensive, but not impossible.

“AsicBoost” is two things:

1. A Bitcoin Proof-of-Work ASIC design that can potentially mine faster that the standard design by fixing the last 64 bytes of the first application of SHA256 (the tail of the block header), and changing the mid-state (the head of the block header), instead of the opposite. This requires fixing and repeatedly using the tail of the header.

2. Several methods to modify the first 64 bytes (head) of the block header, while keeping the tail constant.

I will concentrate on the methods for (2).
There are 2 methods to modify the head (64 bytes) of...

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Merkle trees are a fundamental part of what makes blockchains tick. Although it is definitely theoretically possible to make a blockchain without Merkle trees, simply by creating giant block headers that directly contain every transaction, doing so poses large scalability challenges that arguably puts the ability to trustlessly use blockchains out of the reach of all but the most powerful computers in the long term.

Thanks to Merkle trees, it is possible to build Ethereum nodes that run on all computers and laptops large and small, smart phones and even Internet of things devices such as those that will be produced by Slock.it. So how exactly do these Merkle trees work, and what value do they provide, both now and in the future?

First, the basics. A Merkle tree, in the most general sense, is a way of hashing a large number of chunks of data together which relies on splitting the chunks into buckets, where each bucket contains only a few chunks, then taking the hash of...

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Note: also see the technical papers and introductory decks.


In a traditional blockchain system such as Bitcoin or Ethereum, the blocks record every transaction from genesis forwards and each member of the network participates in checking that the contents of blocks and recorded updates to state are valid. This would never work in a system such as DFINITY because the volumes of data and transactions are too large for any individual process to process - potentially involving exabytes of state and billions of transactions each second. Therefore, DFINITY needs a way to securely validate updates to shards of its state using relatively small subsets of the processes in its network. It will then store just a single Merkle root anchoring the global state in its top-level chain (making it, ironically, far lighter weight than...

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This document provides a fast-paced interactive introduction to basic Bitcoin concepts. The purpose is to give you enough knowledge of the Bitcoin protocol to write micropayments-capable apps and demos. Let’s dive in!

How to learn (enough) Bitcoin in one week

Bitcoin is a very highly interconnected subject and it can be tricky to explain one piece without assuming some knowledge of other pieces (or prerequisites). The approach we recommend you take is as follows:

Step 1: First, go and read the original paper by Satoshi Nakamoto (bitcoin.pdf)

Step 2: Next, set up your development environment using the instructions below.

Step 3: Now go through the Introduction to Bitcoin section and read through the questions to get a high level overview of Bitcoin

Step 4: Next, do the Interactive Introduction section and type in the commands. You won’t understand everything, but will learn by doing - kind of like immersion in a foreign language.

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VP-5 Shipmates

ABBINK, AMEC(AW/NAC) Daniel W. Retired dano8251@ameritech.net "...I served with VP-24 (June 1981 to June 1984), NAMTGD 1011 (August 1984 to August 1987), VP-56 (August 1987 to June 1991), VP-5 (March 1992 to June 1996), RTC Great Lakes (July 1996 to December 2000) and Retired December 2000. I would appreciate any emails from fellow Shipmates..." [31JUL2007]

ABELEIN, CAPT Herman C. Abelein Jr. https://naval-air.org/flightlog/moreinfo.asp?UID=12 "...CAPT Herman C. Abelein Jr., USN - NFL Number: 12 - Date of Birth: 2/4/1930 - Date In: 8/1/1948 - Date Out: 12/1/1976 - City, State: Orange Park, FL - School Attended: Univ Mississippi - Aircraft Flown: P-3, PBM, S2F, AD, FJ - Ship or Unit: VP-5, CO - VP-8 - CTF-72, ChiefofStaff - Pilot Desg.: Patrol Plane Cdr - Theaters, Campaigns, etc.: Korea, Vietnam - Associations/Service Organizations: Assn of Nav Aviation Nav Av Museum Fdn - Highest personal decoration or award: Legion of Merit - Significant...

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