How does the network know the legitimate chain in a double-spend attempt?

How does the network know the legitimate chain in a double-spend attempt?

Apologies if this has been covered, but there's one area of the Bitcoin network that is not clear in my head, and it's intimately linked to the double-spend problem.

Suppose Person A is purchasing an item in a store. They "pay" Person B 1 BTC for a good and broadcast this transaction to the network, which Person B sees as unconfirmed. The transaction is included in a block (Block 1) whose Proof of Work is now being found/solved.

Suppose Person A controls 30% of the Bitcoin mining network (arbitrary high proportion), and has his miners instead mine a different block (Block 2) containing a transaction spending the same BTC to a different wallet controlled by Person A.

Suppose the Proof of Work for Block 2 is, against the odds, obtained first, and the "corrupt" miner who finds the requisite hash broadcasts it to the entire bitcoin network. This is where my understanding breaks down. What exactly happens when the remaining 70% see this transaction? Do they stop mining Block 1? At what point can Block 1 be orphaned?

http://ift.tt/2lsBY4F

Comments

Post a Comment

Popular posts from this blog

QUESTION ABOUT SLOW API

QUESTION ABOUT SLOW API do you know about api requests cryptocurrency exchanges? Simple ticker request may be viewed like this: https://api.kucoin.com/v1/open/tick or like this: https://www.okex.com/api/v1/ticker.do?symbol=ltc_btc Different: in first case we get info about all currencies in one request and then pick up certain symbols and parameters, we need. Symbols are the keys of dictionaries or lists and other params are their values. In second case I should create new request for each currencies I considering. Is it neccesary? If I consider, for instance 60 symbols, and do operations with them in Python - programm bot become slow enough. One-two ticker requests are long about 30 sec - for compare, in first case - 5 sec. How can I solve this problem? Thanks. http://ift.tt/2HpiAM0
Read more

Bitfinex & Market Synergy To Offer Institutional Calibre Cryptocurrency Connectivity

Bitfinex & Market Synergy To Offer Institutional Calibre Cryptocurrency Connectivity Market Synergy GmbH , a Swiss-based organisation which offers institutional cryptocurrency connectivity and security for banks, brokers and hedge funds has been selected by  Bitfinex  to provide robust, high performance connectivity for institutional clients. Market Synergy has designed and built a bespoke network for Bitfinex, hosted in a Swiss data centre in the heart of Crypto Valley. In addition to providing outsourced connectivity and hosting services to Bitfinex, Market Synergy can also manage co-location services for Bitfinex’s institutional clients and offer a FIX feed and ISP link to the digital asset gateway which Bitfinex recently launched in collaboration with Connamara . Market Synergy is a separate company within the FXecosystem Group , which also comprises of FXecosystem and Bondecosystem, both of which are institutional market leaders in outsourced connectiv...
Read more

How a transaction proves its ownership of the its source, which can be one or multiple unspent output?

How a transaction proves its ownership of the its source, which can be one or multiple unspent output? I read the following from the book << Mastering Bitcoin >> "As you may notice, the transaction contains an empty scriptSig because we haven’t signed it yet. Without a signature, this transaction is meaningless, we haven’t yet proven that we own the address from which the unspent output is sourced." I am wondering how a signature can prove that this transaction owns the address from which the unspent output is sourced? https://ift.tt/2r4Ni7x
Read more