Selfish mining bitcointalk news
Corresponding author: Wei Li. The past three years have seen the rapid increase of Bitcoin difficulty, which has led to a substantial variance in solo mining. As a result, miners tend to join a large open pool to get a more stable reward. In a sense, this is a manifestation of Bitcoin that tends to be centralized.
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Selfish mining bitcointalk news
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- crypto trading glossary
- Where Is Current Research on Blockchain Technology?—A Systematic Review
- Irreversible Transactions
- Meet the face of Tee See Tee(me...).
- Elon Musk says he talked to 'North American Bitcoin miners,' sending bitcoin price surging
- Bitcoin Mining Now Dominated by One Pool
- A Survey on Security and Privacy Issues of Bitcoin
- Three Cryptocurrencies Hacked in One week, Loss amounts to $20 Million
- Identity on Blockchain (Part I)
- Journal of Information Technologies
crypto trading glossary
In exchange for the incentive, the miners are expected to honestly maintain the blockchain. Since its launch in , Bitcoin economy has grown at an enormous rate, and it is now worth about 40 billions of dollars. This exponential growth in the market value of Bitcoin motivates adversaries to exploit weaknesses for profit, and researchers to identify vulnerabilities in the system, propose countermeasures, and predict upcoming trends. In this paper, we present a systematic survey on security and privacy aspects of Bitcoin.
We start by presenting an overview of the Bitcoin protocol and discuss its major components with their functionality and interactions. We review the existing vulnerabilities in Bitcoin which leads to the execution of various security threats in the Bitcoin system. We discuss the feasibility and robustness of the state-of-the-art security solutions. We present privacy and anonymity considerations and discuss the threats to enabling user privacy, along with the analysis of existing privacy-preserving solutions.
Finally, we summarize the critical open challenges and suggest directions for future research towards provisioning stringent security and privacy techniques for Bitcoin. In such electronic payment systems, the consensus is reached via a trusted centralized authority that may appear as a bank, a Chartered Accountant CA , a notary, or any other trusted service. The use of such third party authorities as an authenticator increases the cost of trading because a nominal fee is deducted as a payment or commission by these third parties.
Bitcoin is a cryptographically secure decentralized peer-to-peer P2P electronic payment system, and it enables transactions involving virtual currency in the form of digital tokens. Such digital tokens, also called Bitcoin Coins 1 1 1 In rest of the paper, we will use the terms coin and BTCs interchangeably. BTCs are cryptocurrencies whose implementation relies on cryptography techniques.
The cryptography is used in order to control the generation of new coins and to securely validate the transactions without involving any central authorities. In Bitcoin, the trust in a third-party such as a bank is replaced by a cryptographic Proof-of-Work PoW scheme that uses a public digital append-only ledger called blockchain.
This ledger keeps records for all coin balances and transactions in the whole Bitcoin system that are announced, agreed upon, and that is completed in the past. The blockchain is accessible to all the network nodes or participants in order to enforce transparency in the system. Until today, due to the incomplete existence of robust theoretical base, security research community was dismissing the use of Bitcoin.
Existing security solutions in Bitcoin lacks the required measures that could ensure an adequate level of security to its users. We believe that security solutions should target all the major protocols running critical functions in the Bitcoin system.
These include blockchain protocol, peer-to-peer communication protocols, cryptographic protocols, and key management protocols. However, online communities have already started to adapt the Bitcoin, as it is believed that it will soon take over the online trading business.
Wiki leaks also support the use of Litecoin, another cryptocurrency, for the same reason [ 3 ]. Recently, Bitcoin technology is grabbing a lot of attention from government bodies. This is due to its increasing use by the malicious users to undermine legal controls. According to [ 5 ] , the current Bitcoin exchange rate is approximately dollars from around dollars in mid The major technologies such blockchain and consensus protocols that makes the Bitcoin systems a huge success will be now envisioned in various next generation applications, which includes smart trading in smart grids [ 6 ] , Internet of Things IoT [ 7 ] [ 8 ] , vehicular networks [ 9 ] , healthcare data management, and smart cities [ 10 ] [ 11 ] , to name a few.
As the length of popularity largely depends on the amount of security built on the system which surpasses all its other benefits, we aim to investigate the associated security and privacy issues in Bitcoin systems.
In this paper, we present a comprehensive survey specifically targeting the security and privacy aspects in Bitcoin systems. We discuss the state-of-the-art attack vector which includes various user security and transaction anonymity threats that limits or threatens the applicability or continuity of Bitcoins in real-world applications and services. We also discuss the efficiency of various security solutions that are proposed over the years to address the security and privacy challenges in Bitcoin system.
In addition, we discuss the issues of user privacy and transaction anonymity along with a large array of research that has been done recently for enabling privacy and improving anonymity in Bitcoins. In literature, authors in [ 12 ] , provides a comprehensive technical survey on decentralized digital currencies with mainly emphasizing on Bitcoins.
The authors explore the technical background of Bitcoin system and discuss the implications of the central design decisions for Bitcoin protocols. However, the paper lacks a detailed survey about security and privacy attacks and their associated solutions. In particular, the main contributions that this survey provides are as follow. We present the required background knowledge for Bitcoin, its functionalities, and related concepts. We cover all the existing security and privacy-related threats that are associated with different components of Bitcoin system at various levels of its overall operation.
We discuss the efficiency and limitations of the state-of-the-art solutions that address the security threats and enables strong privacy in Bitcoin systems, thus providing a holistic technical perspective on these issues in Bitcoin. By doing so, we aim to assist interested readers in understanding existing security and privacy-related challenges, estimate the possible damage caused by these, and to improve the techniques for detection and containment of identified existing and future attacks in Bitcoins.
The rest of the paper is organized as follow. In Section II , we present a brief overview of Bitcoin which includes the description of its major components along with their functionalities and interactions. In Section III , we discuss a number of security threats associated with the development, implementation, and use of Bitcoin systems.
In Section IV , we discuss the state-of-the-art proposals that either countermeasure a security threat or enhances the existing security in Bitcoins. In Section V , we discuss the anonymity and privacy threats in Bitcoins along with their existing solutions. Finally, we conclude the paper in Section VII.
Bitcoin is a decentralized electronic payment system introduced by Nakamoto [ 1 ]. It is based on peer-to-peer network and a probabilistic distributed consensus protocol. In Bitcoin, electronic payments are done by generating transactions that transfer coins among Bitcoin users.
The source and destination addresses are represented by a cryptographic hash of a public key of the respective user. A user can have multiple addresses by generating multiple public keys and these addresses are associated be one or more of her wallets [ 13 ] , but the private key of the user is required to spend coins in form of the digitally signed transactions.
Using the hash of the public key as a receiving or sending address provides Bitcoin users a certain degree of anonymity, and it is recommended the practice to use different public keys for each transaction. In a Bitcoin system, there are three major components, namely: users or customers , miners, management staff, Bitcoin exchanges, and wallets.
Figure 1 shows the main functions and means to achieve those functions for all these components. A transaction to transfer the coins consists of a set of inputs and outputs, and it has a unique identifier. The miner advertises a block to the rest of the Bitcoin network as soon as it completes its processing or validation in order to claim the mining rewards. The miner who mines a block receives a reward or incentive when the mined block is successfully added to the blockchain. We now present an overview of the major technical components and operational features that are essential for the practical realization of the Bitcoin systems.
Bitcoin uses transactions to move coins from one user wallet to another. In particular, the coins are represented in the form of transactions, more specifically, a chain of transactions. The key values in a transaction are one or more inputs, one or more outputs, and a unique transaction identifier T x i d as depicted in Figure 2 , where T x n is the n t h transaction in the blockchain. Briefly, each input belongs to a particular user, and it specifies the unspent coins, the hash of its previous transaction, and an index to one of its output.
To authorize a transaction input, the corresponding user of the input provides the public key and the signature which is generated using her private key. As an input specifies the total number of unspent coins of a user, in each transaction the user has to operate on all of its remaining coins.
For instance, B o b has 50 coins and he wants to transfer 5 coins to A l i c e. For this transaction, B o b has to make two different inputs, one showing a transaction in which 5 coins are transferred to Alice, and another showing a transfer of 45 coins in one or more wallet s owned by B o b. With this approach, the Bitcoin achieves two goals: i it implements the idea of c h a n g e , and ii one can easily identify the unspent coins or balance of a user by only looking the outputs of its previous transaction.
An output in a transaction specifies the number of coins being transferred along with the Bitcoin address of the new owner. These inputs and outputs are managed using a Forth-like scripting language which dictates the essential conditions to claim the coins. Unlike central bank in which all the transactions are verified, processed, and recorded in a centralized private ledger, in Bitcoin every user acts as a bank and keep a copy of this ledger.
In Bitcoin, the role of the distributed ledger is played by the so-called blockchain. However, storing multiple copies of the blockchain in the Bitcoin network adds new vulnerabilities in the system such as keeping the global view of the blockchain consistent. For instance, a user say A l i c e could generate two different transactions simultaneously using the same set of coins to two different receivers say, B o b and C a r o l.
This type of malicious behavior by a Bitcoin user is termed as a double spending. If both the receiver processes the transaction independently based on their local view of the blockchain, and the transaction verification is successful, this leaves the blockchain into an inconsistent state. The main requirement to avoid the above problem is two-folded: i distribute the transaction verification process to ensure the correctness of the transaction, and ii everyone in the network should know quickly about a successfully processed transaction to ensure the consistent state of the blockchain.
To fulfill the aforementioned requirements, Bitcoin uses the concept of Proof-of-Work PoW and a probabilistic distributed consensus protocol. The distributed transaction verification process ensures that a majority of miners will verify the legitimacy of a transaction before it is added in the blockchain. In this way, whenever the blockchain goes into an inconsistent state, all the nodes update their local copy of blockchain with the state on which a majority of miners agree, thus the correct state of the blockchain is obtained by election.
However, this scheme is vulnerable to the sybil attacks [ 15 ]. With sybil attack, a miner creates multiple virtual nodes in the Bitcoin network and these nodes could disrupt the election process by injecting false information in the network such as voting positive for a faulty transaction.
Bitcoin counters the sybil attacks by making use of PoW in which to verify a transaction, the miners have to perform some sort of computational task to prove that they are not virtual entities. The PoW consists of a complex cryptographic math puzzle [ 16 ] , and it imposes a high level of computational cost on the transaction verification process, thus the verification will be dependent on the computing power of a miner, instead of the number of possibly virtual identities.
The main idea is that it is much harder to fake the computing resources in the Bitcoin network than it is to perform a sybil attack. In practical, the miners do not verify individual transactions, instead they collect pending transactions to form a block. The miners validate a block by calculating the hash of that block and vary a nonce value until the hash value becomes lower or equal to the given target value.
Calculating the desired hash value is computationally difficult. Bitcoin uses the SHA hash function [ 17 ]. Unless the cryptographic hash function finds the required hash value, the only option is to try different nonces until a solution a hash value lower than target value is discovered. Consequently, the difficulty of the puzzle depends on the target value, i.
Once a miner calculates such a hash value for a block, it immediately broadcast the block in the network along with the calculated hash value, and it also appends the block in the public ledger i. The rest of the miners when receiving a mined block can quickly verify its correctness by comparing the hash value given in the received block with the target value.
The miners will also update their local blockchain by adding the newly mined block. Once a block is successfully added in the blockchain i. Figure 3 depicts a high-level view of the Bitcoin transaction execution process, which starts from a transaction creation step and it ends when a block containing this transaction is mined successfully by miners residing in the Bitcoin network. The chance of being the first to solve the puzzle is higher for the miners who owns or controls more number of computing resources.
By this rule, a miner with higher computing resources can always increase her chances to win the reward. To enforce stability, fairness, and reasonable waiting times for block validation, the t a r g e t value is adjusted after every 2, blocks.
Where Is Current Research on Blockchain Technology?—A Systematic Review
In a peer-to-peer connection, two or more computers network with each other without a centralized third party being used as an intermediary. Pre-Sale A period before an ICO goes public when private investors or community members are able to buy the cryptocurrency. Private Key A string of numbers and letters that are used to access your crypto trading glossary. While your wallet is represented by a public key, the private key is the password you should protect with your life. You need your private key when selling or withdrawing cryptocurrencies, as it acts as your digital signature.
In exchange for the incentive, the miners are expected to honestly maintain the blockchain. Since its launch in , Bitcoin economy has grown at an enormous rate, and it is now worth about 40 billions of dollars. This exponential growth in the market value of Bitcoin motivates adversaries to exploit weaknesses for profit, and researchers to identify vulnerabilities in the system, propose countermeasures, and predict upcoming trends. In this paper, we present a systematic survey on security and privacy aspects of Bitcoin. We start by presenting an overview of the Bitcoin protocol and discuss its major components with their functionality and interactions. We review the existing vulnerabilities in Bitcoin which leads to the execution of various security threats in the Bitcoin system. We discuss the feasibility and robustness of the state-of-the-art security solutions. We present privacy and anonymity considerations and discuss the threats to enabling user privacy, along with the analysis of existing privacy-preserving solutions. Finally, we summarize the critical open challenges and suggest directions for future research towards provisioning stringent security and privacy techniques for Bitcoin.
Meet the face of Tee See Tee(me...).
Stratum, the de-facto mining communication protocol used by blockchain based cryptocurrency systems, enables miners to reliably and efficiently fetch jobs from mining pool servers. We introduce StraTap and ISP Log attacks, that infer miner earnings if given access to miner communications, or even their logs. We develop BiteCoin, an active attack that hijacks shares submitted by miners, and their associated payouts. We build BiteCoin on WireGhost, a tool we developed to hijack and surreptitiously maintain Stratum connections. Our attacks reveal that securing Stratum through pervasive encryption is not only undesirable due to large overheads , but also ineffective: an adversary can predict miner earnings even when given access to only packet timestamps.
Elon Musk says he talked to 'North American Bitcoin miners,' sending bitcoin price surging
Try out PMC Labs and tell us what you think. Learn More. Blockchain is a decentralized transaction and data management technology developed first for Bitcoin cryptocurrency. The interest in Blockchain technology has been increasing since the idea was coined in The reason for the interest in Blockchain is its central attributes that provide security, anonymity and data integrity without any third party organization in control of the transactions, and therefore it creates interesting research areas, especially from the perspective of technical challenges and limitations. In this research, we have conducted a systematic mapping study with the goal of collecting all relevant research on Blockchain technology.
Bitcoin Mining Now Dominated by One Pool
April 10, Comments. I'm Beau, and I am the owner, designer, operator, salesperson, janitor, folder, quality controller, web builder, and delivery driver for Tee See Tee. This is not easy for me. I am not "shy" by today's standards, but I am not an extrovert either. So to make a decision to be out there in front of the masses, selling, schmoozing, talking about our process and products, I am getting nervous just thinking about it! But it needs to happen. I realized earlier this year that the last couple years we spent so much energy on designing, printing, and delivering tens of thousands of t-shirts to our retail partners all over Michigan, that we stopped doing things like street fairs, music festivals, and trunk shows. In our first year of business, Tee See Tee did about 30 different shows during the summer.
A Survey on Security and Privacy Issues of Bitcoin
Bitcoin is no longer decentralized. GHash can control Bitcoin transactions. Yes, it is.
Three Cryptocurrencies Hacked in One week, Loss amounts to $20 MillionRELATED VIDEO: Bitcoin operation ignites debate around Pennsylvania coal mining waste
This article belongs to the Glossary of decentralised technosocial systems , a special section of Internet Policy Review. In the context of blockchain networks, mining describes a permissionless process intended to ensure the global consistency of a decentralised ledger. Mining requires the consumption of a costly computational resource to participate in a probabilistic competition that confers specific privileges to a node. These privileges typically relate to the proposal of a new block, including the identity and order of transactions contained within. Cryptocurrency mining was initially understood to refer to processes incorporating proof-of-work PoW i.
Identity on Blockchain (Part I)
When used correctly, Bitcoin's base layer transactions on the blockchain are irreversible and final. It's no exaggeration to say that the entirety of bitcoin's system of blockchain , mining , proof of work , difficulty etc, exist to produce this history of transactions that is computationally impractical to modify. In the literature on electronic cash, this property was often refer to as "solving the double-spending problem". Double-spending is the result of successfully spending some money more than once. Bitcoin users protect themselves from double spending fraud by waiting for confirmations when receiving payments on the blockchain, the transactions become more irreversible as the number of confirmations rises.
Journal of Information Technologies
An attacker was able to manipulate a bug in the Verge code that allowed miners to set false timestamps on blocks and then quickly mine new blocks in succession. Since more and more blocks got added with a bogus timestamp, the difficulty kept on reducing. This Time-warp attack allowed the miners to mine blocks eventually with virtually zero difficulty. But to really reap the benefits the attackers had to control atleast 51 percent of the hashpower which they did by getting control over two of the five algorithms Verge uses for PoW.