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Address ›
0x6dC0868d33F556e77252280696158defb3D64811
Overview
Balance:
0.000073924961754 ETH
ETH Value:
$0.24
(@ $3,210.79/ETH)
Token:
$0.00
3
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0x63291...a294d0
Transfer
0xD78B...E0cDe0
IN
0x6dC0...D64811
1.00
环球股 (HQG)
457 days 19 hrs ago
0xd458e...9170c9
Remove Liquidity ETH With Permit Supporting Fee On Transfer Tokens
Uniswap: V2 Router
IN
0x6dC0...D64811
44,603,225.73
Bitcoin As A State Transition System \n \n From a technical standpoint, the ledger of a cryptocurrency such as Bitcoin can be thought of as a state transition system, where there is a *state* consisting of the ownership status of all existing bitcoins and a *state transition function* that takes a state and a transaction and outputs a new state which is the result. In a standard banking system, for example, the state is a balance sheet, a transaction is a request to move $X from A to B, and the state transition function reduces the value in A's account by $X and increases the value in B's account by $X. If A's account has less than $X in the first place, the state transition function returns an error. Hence, one can formally define: \n The *state* in Bitcoin is the collection of all coins (technically, *unspent transaction outputs* or UTXO) that have been minted and not yet spent, with each UTXO having a denomination and an owner (defined by a 20-byte address which is essentially a cryptographic public keyfn1). A transaction contains one or more inputs, with each input containing a reference to an existing UTXO and a cryptographic signature produced by the private key associated with the owner's address, and one or more outputs, with each output containing a new UTXO to be added to the state. The state transition function APPLY(S,TX) -> S' can be defined roughly as follows: For each input in TX: If the referenced UTXO is not in S, return an error. If the provided signature does not match the owner of the UTXO, return an error. If the sum of the denominations of all input UTXO is less than the sum of the denominations of all output UTXO, return an error. Return S with all input UTXO removed and all output UTXO added The first half of the first step prevents transaction senders from spending coins that do not exist, the second half of the first step prevents transaction senders from spending other people's coins, and the second step enforces conservation of value. In order to use this for payment, the protocol is as follows. Suppose Alice wants to send 11.7 BTC to Bob. First, Alice will look for a set of available UTXO that she owns that totals up to at least 11.7 BTC. Realistically, Alice will not be able to get exactly 11.7 BTC; say that the smallest she can get is 6+4+2=12. She then creates a transaction with those three inputs and two outputs. The first output will be 11.7 BTC with Bob's address as its owner, and the second output will be the remaining 0.3 BTC *change*, with the owner being Alice herself. \n \n Mining \n \n If we had access to a trustworthy centralized service, this system would be trivial to implement; it could simply be coded exactly as described, using a centralized server's hard drive to keep track of the state. However, with Bitcoin we are trying to build a decentralized currency system, so we will need to combine the state transaction system with a consensus system in order to ensure that everyone agrees on the order of transactions. Bitcoin's decentralized consensus process requires nodes in the network to continuously attempt to produce packages of transactions called *blocks*. The network is intended to produce roughly one block every ten minutes, with each block containing a timestamp, a nonce, a reference to (ie. hash of) the previous block and a list of all of the transactions that have taken place since the previous block. Over time, this creates a persistent, ever-growing, *blockchain* that constantly updates to represent the latest state of the Bitcoin ledger. The algorithm for checking if a block is valid, expressed in this paradigm, is as follows: Check if the previous block referenced by the block exists and is valid. Check that the timestamp of the block is greater than that of the previous blockfn2 and less than 2 hours into the future Check that the proof-of-work on the block is valid. Let S[0] be the state at the end of the previous block. Suppose TX is the block's transaction list with n transactions. For all i in 0...n-1, set S[i+1] = APPLY(S[i],TX[i]) If any application returns an error, exit and return false. Return true, and register S[n] as the state at the end of this block. Essentially, each transaction in the block must provide a valid state transition from what was the canonical state before the transaction was executed to some new state. Note that the state is not encoded in the block in any way; it is purely an abstraction to be remembered by the validating node and can only be (securely) computed for any block by starting from the genesis state and sequentially applying every transaction in every block. Additionally, note that the order in which the miner includes transactions into the block matters; if there are two transactions A and B in a block such that B spends a UTXO created by A, then the block will be valid if A comes before B but not otherwise. The one validity condition present in the above list that is not found in other systems is the requirement for *proof-of-work*. The precise condition is that the double-SHA256 hash of every block, treated as a 256-bit number, must be less than a dynamically adjusted target, which as of the time of this writing is approximately 2187. The purpose of this is to make block creation computationally *hard*, thereby preventing sybil attackers from remaking the entire blockchain in their favor. Because SHA256 is designed to be a completely unpredictable pseudorandom function, the only way to create a valid block is simply trial and error, repeatedly incrementing the nonce and seeing if the new hash matches. At the current target of ~2187, the network must make an average of ~269 tries before a valid block is found; in general, the target is recalibrated by the network every 2016 blocks so that on average a new block is produced by some node in the network every ten minutes. In order to compensate miners for this computational work, the miner of every block is entitled to include a transaction giving themselves 25 BTC out of nowhere. Additionally, if any transaction has a higher total denomination in its inputs than in its outputs, the difference also goes to the miner as a *transaction fee*. Incidentally, this is also the only mechanism by which BTC are issued; the genesis state contained no coins at all. In order to better understand the purpose of mining, let us examine what happens in the event of a malicious attacker. Since Bitcoin's underlying cryptography is known to be secure, the attacker will target the one part of the Bitcoin system that is not protected by cryptography directly: the order of transactions. The attacker's strategy is simple: Send 100 BTC to a merchant in exchange for some product (preferably a rapid-delivery digital good) ait for the delivery of the product Produce another transaction sending the same 100 BTC to himself Try to convince the network that his transaction to himself was the one that came first. Once step (1) has taken place, after a few minutes some miner will include the transaction in a block, say block number 270000. After about one hour, five more blocks will have been added to the chain after that block, with each of those blocks indirectly pointing to the transaction and thus *confirming* it. At this point, the merchant will accept the payment as finalized and deliver the product; since we are assuming this is a digital good, delivery is instant. Now, the attacker creates another transaction sending the 100 BTC to himself. If the attacker simply releases it into the wild, the transaction will not be processed; miners will attempt to run APPLY(S,TX) and notice that TX consumes a UTXO which is no longer in the state. So instead, the attacker creates a *fork* of the blockchain, starting by mining another version of block 270000 pointing to the same block 269999 as a parent but with the new transaction in place of the old one. Because the block data is different, this requires redoing the proof-of-work. Furthermore, the attacker's new version of block 270000 has a different hash, so the original blocks 270001 to 270005 do not *point* to it; thus, the original chain and the attacker's new chain are completely separate. The rule is that in a fork the longest blockchain is taken to be the truth, and so legitimate miners will work on the 270005 chain while the attacker alone is working on the 270000 chain. In order for the attacker to make his blockchain the longest, he would need to have more computational power than the rest of the network combined in order to catch up (hence, *51% attack*). (GENESIS)
459 days 21 hrs ago
0xd458e...9170c9
Remove Liquidity ETH With Permit Supporting Fee On Transfer Tokens
0x6dC0...D64811
OUT
0xcF04...8a7608
5,366.56
Uniswap V2 (UNI-V2)
459 days 21 hrs ago
0xf8715...ca1703
Mine Genesis Block
Null: 0x000...000
IN
0x6dC0...D64811
5,366.56
Uniswap V2 (UNI-V2)
459 days 21 hrs ago
0xd8d52...e6f5c9
Transfer
0x6dC0...D64811
OUT
Bitcoin As A State Transition System From a technical standpoint, the ledger of a cryptocurrency
72,000,000.00
Bitcoin As A State Transition System \n \n From a technical standpoint, the ledger of a cryptocurrency such as Bitcoin can be thought of as a state transition system, where there is a *state* consisting of the ownership status of all existing bitcoins and a *state transition function* that takes a state and a transaction and outputs a new state which is the result. In a standard banking system, for example, the state is a balance sheet, a transaction is a request to move $X from A to B, and the state transition function reduces the value in A's account by $X and increases the value in B's account by $X. If A's account has less than $X in the first place, the state transition function returns an error. Hence, one can formally define: \n The *state* in Bitcoin is the collection of all coins (technically, *unspent transaction outputs* or UTXO) that have been minted and not yet spent, with each UTXO having a denomination and an owner (defined by a 20-byte address which is essentially a cryptographic public keyfn1). A transaction contains one or more inputs, with each input containing a reference to an existing UTXO and a cryptographic signature produced by the private key associated with the owner's address, and one or more outputs, with each output containing a new UTXO to be added to the state. The state transition function APPLY(S,TX) -> S' can be defined roughly as follows: For each input in TX: If the referenced UTXO is not in S, return an error. If the provided signature does not match the owner of the UTXO, return an error. If the sum of the denominations of all input UTXO is less than the sum of the denominations of all output UTXO, return an error. Return S with all input UTXO removed and all output UTXO added The first half of the first step prevents transaction senders from spending coins that do not exist, the second half of the first step prevents transaction senders from spending other people's coins, and the second step enforces conservation of value. In order to use this for payment, the protocol is as follows. Suppose Alice wants to send 11.7 BTC to Bob. First, Alice will look for a set of available UTXO that she owns that totals up to at least 11.7 BTC. Realistically, Alice will not be able to get exactly 11.7 BTC; say that the smallest she can get is 6+4+2=12. She then creates a transaction with those three inputs and two outputs. The first output will be 11.7 BTC with Bob's address as its owner, and the second output will be the remaining 0.3 BTC *change*, with the owner being Alice herself. \n \n Mining \n \n If we had access to a trustworthy centralized service, this system would be trivial to implement; it could simply be coded exactly as described, using a centralized server's hard drive to keep track of the state. However, with Bitcoin we are trying to build a decentralized currency system, so we will need to combine the state transaction system with a consensus system in order to ensure that everyone agrees on the order of transactions. Bitcoin's decentralized consensus process requires nodes in the network to continuously attempt to produce packages of transactions called *blocks*. The network is intended to produce roughly one block every ten minutes, with each block containing a timestamp, a nonce, a reference to (ie. hash of) the previous block and a list of all of the transactions that have taken place since the previous block. Over time, this creates a persistent, ever-growing, *blockchain* that constantly updates to represent the latest state of the Bitcoin ledger. The algorithm for checking if a block is valid, expressed in this paradigm, is as follows: Check if the previous block referenced by the block exists and is valid. Check that the timestamp of the block is greater than that of the previous blockfn2 and less than 2 hours into the future Check that the proof-of-work on the block is valid. Let S[0] be the state at the end of the previous block. Suppose TX is the block's transaction list with n transactions. For all i in 0...n-1, set S[i+1] = APPLY(S[i],TX[i]) If any application returns an error, exit and return false. Return true, and register S[n] as the state at the end of this block. Essentially, each transaction in the block must provide a valid state transition from what was the canonical state before the transaction was executed to some new state. Note that the state is not encoded in the block in any way; it is purely an abstraction to be remembered by the validating node and can only be (securely) computed for any block by starting from the genesis state and sequentially applying every transaction in every block. Additionally, note that the order in which the miner includes transactions into the block matters; if there are two transactions A and B in a block such that B spends a UTXO created by A, then the block will be valid if A comes before B but not otherwise. The one validity condition present in the above list that is not found in other systems is the requirement for *proof-of-work*. The precise condition is that the double-SHA256 hash of every block, treated as a 256-bit number, must be less than a dynamically adjusted target, which as of the time of this writing is approximately 2187. The purpose of this is to make block creation computationally *hard*, thereby preventing sybil attackers from remaking the entire blockchain in their favor. Because SHA256 is designed to be a completely unpredictable pseudorandom function, the only way to create a valid block is simply trial and error, repeatedly incrementing the nonce and seeing if the new hash matches. At the current target of ~2187, the network must make an average of ~269 tries before a valid block is found; in general, the target is recalibrated by the network every 2016 blocks so that on average a new block is produced by some node in the network every ten minutes. In order to compensate miners for this computational work, the miner of every block is entitled to include a transaction giving themselves 25 BTC out of nowhere. Additionally, if any transaction has a higher total denomination in its inputs than in its outputs, the difference also goes to the miner as a *transaction fee*. Incidentally, this is also the only mechanism by which BTC are issued; the genesis state contained no coins at all. In order to better understand the purpose of mining, let us examine what happens in the event of a malicious attacker. Since Bitcoin's underlying cryptography is known to be secure, the attacker will target the one part of the Bitcoin system that is not protected by cryptography directly: the order of transactions. The attacker's strategy is simple: Send 100 BTC to a merchant in exchange for some product (preferably a rapid-delivery digital good) ait for the delivery of the product Produce another transaction sending the same 100 BTC to himself Try to convince the network that his transaction to himself was the one that came first. Once step (1) has taken place, after a few minutes some miner will include the transaction in a block, say block number 270000. After about one hour, five more blocks will have been added to the chain after that block, with each of those blocks indirectly pointing to the transaction and thus *confirming* it. At this point, the merchant will accept the payment as finalized and deliver the product; since we are assuming this is a digital good, delivery is instant. Now, the attacker creates another transaction sending the 100 BTC to himself. If the attacker simply releases it into the wild, the transaction will not be processed; miners will attempt to run APPLY(S,TX) and notice that TX consumes a UTXO which is no longer in the state. So instead, the attacker creates a *fork* of the blockchain, starting by mining another version of block 270000 pointing to the same block 269999 as a parent but with the new transaction in place of the old one. Because the block data is different, this requires redoing the proof-of-work. Furthermore, the attacker's new version of block 270000 has a different hash, so the original blocks 270001 to 270005 do not *point* to it; thus, the original chain and the attacker's new chain are completely separate. The rule is that in a fork the longest blockchain is taken to be the truth, and so legitimate miners will work on the 270005 chain while the attacker alone is working on the 270000 chain. In order for the attacker to make his blockchain the longest, he would need to have more computational power than the rest of the network combined in order to catch up (hence, *51% attack*). (GENESIS)
459 days 21 hrs ago
0xa80f6...40f863
Null: 0x000...000
IN
0x6dC0...D64811
72,000,000.00
Bitcoin As A State Transition System \n \n From a technical standpoint, the ledger of a cryptocurrency such as Bitcoin can be thought of as a state transition system, where there is a *state* consisting of the ownership status of all existing bitcoins and a *state transition function* that takes a state and a transaction and outputs a new state which is the result. In a standard banking system, for example, the state is a balance sheet, a transaction is a request to move $X from A to B, and the state transition function reduces the value in A's account by $X and increases the value in B's account by $X. If A's account has less than $X in the first place, the state transition function returns an error. Hence, one can formally define: \n The *state* in Bitcoin is the collection of all coins (technically, *unspent transaction outputs* or UTXO) that have been minted and not yet spent, with each UTXO having a denomination and an owner (defined by a 20-byte address which is essentially a cryptographic public keyfn1). A transaction contains one or more inputs, with each input containing a reference to an existing UTXO and a cryptographic signature produced by the private key associated with the owner's address, and one or more outputs, with each output containing a new UTXO to be added to the state. The state transition function APPLY(S,TX) -> S' can be defined roughly as follows: For each input in TX: If the referenced UTXO is not in S, return an error. If the provided signature does not match the owner of the UTXO, return an error. If the sum of the denominations of all input UTXO is less than the sum of the denominations of all output UTXO, return an error. Return S with all input UTXO removed and all output UTXO added The first half of the first step prevents transaction senders from spending coins that do not exist, the second half of the first step prevents transaction senders from spending other people's coins, and the second step enforces conservation of value. In order to use this for payment, the protocol is as follows. Suppose Alice wants to send 11.7 BTC to Bob. First, Alice will look for a set of available UTXO that she owns that totals up to at least 11.7 BTC. Realistically, Alice will not be able to get exactly 11.7 BTC; say that the smallest she can get is 6+4+2=12. She then creates a transaction with those three inputs and two outputs. The first output will be 11.7 BTC with Bob's address as its owner, and the second output will be the remaining 0.3 BTC *change*, with the owner being Alice herself. \n \n Mining \n \n If we had access to a trustworthy centralized service, this system would be trivial to implement; it could simply be coded exactly as described, using a centralized server's hard drive to keep track of the state. However, with Bitcoin we are trying to build a decentralized currency system, so we will need to combine the state transaction system with a consensus system in order to ensure that everyone agrees on the order of transactions. Bitcoin's decentralized consensus process requires nodes in the network to continuously attempt to produce packages of transactions called *blocks*. The network is intended to produce roughly one block every ten minutes, with each block containing a timestamp, a nonce, a reference to (ie. hash of) the previous block and a list of all of the transactions that have taken place since the previous block. Over time, this creates a persistent, ever-growing, *blockchain* that constantly updates to represent the latest state of the Bitcoin ledger. The algorithm for checking if a block is valid, expressed in this paradigm, is as follows: Check if the previous block referenced by the block exists and is valid. Check that the timestamp of the block is greater than that of the previous blockfn2 and less than 2 hours into the future Check that the proof-of-work on the block is valid. Let S[0] be the state at the end of the previous block. Suppose TX is the block's transaction list with n transactions. For all i in 0...n-1, set S[i+1] = APPLY(S[i],TX[i]) If any application returns an error, exit and return false. Return true, and register S[n] as the state at the end of this block. Essentially, each transaction in the block must provide a valid state transition from what was the canonical state before the transaction was executed to some new state. Note that the state is not encoded in the block in any way; it is purely an abstraction to be remembered by the validating node and can only be (securely) computed for any block by starting from the genesis state and sequentially applying every transaction in every block. Additionally, note that the order in which the miner includes transactions into the block matters; if there are two transactions A and B in a block such that B spends a UTXO created by A, then the block will be valid if A comes before B but not otherwise. The one validity condition present in the above list that is not found in other systems is the requirement for *proof-of-work*. The precise condition is that the double-SHA256 hash of every block, treated as a 256-bit number, must be less than a dynamically adjusted target, which as of the time of this writing is approximately 2187. The purpose of this is to make block creation computationally *hard*, thereby preventing sybil attackers from remaking the entire blockchain in their favor. Because SHA256 is designed to be a completely unpredictable pseudorandom function, the only way to create a valid block is simply trial and error, repeatedly incrementing the nonce and seeing if the new hash matches. At the current target of ~2187, the network must make an average of ~269 tries before a valid block is found; in general, the target is recalibrated by the network every 2016 blocks so that on average a new block is produced by some node in the network every ten minutes. In order to compensate miners for this computational work, the miner of every block is entitled to include a transaction giving themselves 25 BTC out of nowhere. Additionally, if any transaction has a higher total denomination in its inputs than in its outputs, the difference also goes to the miner as a *transaction fee*. Incidentally, this is also the only mechanism by which BTC are issued; the genesis state contained no coins at all. In order to better understand the purpose of mining, let us examine what happens in the event of a malicious attacker. Since Bitcoin's underlying cryptography is known to be secure, the attacker will target the one part of the Bitcoin system that is not protected by cryptography directly: the order of transactions. The attacker's strategy is simple: Send 100 BTC to a merchant in exchange for some product (preferably a rapid-delivery digital good) ait for the delivery of the product Produce another transaction sending the same 100 BTC to himself Try to convince the network that his transaction to himself was the one that came first. Once step (1) has taken place, after a few minutes some miner will include the transaction in a block, say block number 270000. After about one hour, five more blocks will have been added to the chain after that block, with each of those blocks indirectly pointing to the transaction and thus *confirming* it. At this point, the merchant will accept the payment as finalized and deliver the product; since we are assuming this is a digital good, delivery is instant. Now, the attacker creates another transaction sending the 100 BTC to himself. If the attacker simply releases it into the wild, the transaction will not be processed; miners will attempt to run APPLY(S,TX) and notice that TX consumes a UTXO which is no longer in the state. So instead, the attacker creates a *fork* of the blockchain, starting by mining another version of block 270000 pointing to the same block 269999 as a parent but with the new transaction in place of the old one. Because the block data is different, this requires redoing the proof-of-work. Furthermore, the attacker's new version of block 270000 has a different hash, so the original blocks 270001 to 270005 do not *point* to it; thus, the original chain and the attacker's new chain are completely separate. The rule is that in a fork the longest blockchain is taken to be the truth, and so legitimate miners will work on the 270005 chain while the attacker alone is working on the 270000 chain. In order for the attacker to make his blockchain the longest, he would need to have more computational power than the rest of the network combined in order to catch up (hence, *51% attack*). (GENESIS)
459 days 21 hrs ago
0xf50bf...9df72c
Transfer
0x6dC0...D64811
OUT
Introduction to Bitcoin and Existing Concepts History The concept of decentralized digital c
2,400.00
Uniswap V2 (UNI-V2)
460 days 14 hrs ago
0x01d39...7bde50
Mine Genesis Block
Null: 0x000...000
IN
0x6dC0...D64811
2,400.00
Uniswap V2 (UNI-V2)
460 days 14 hrs ago
0x68dde...78aa9e
Transfer
0x6dC0...D64811
OUT
Introduction to Bitcoin and Existing Concepts History The concept of decentralized digital c
72,000,000.00
Introduction to Bitcoin and Existing Concepts \n \n History \n \n The concept of decentralized digital currency, as well as alternative applications like property registries, has been around for decades. The anonymous e-cash protocols of the 1980s and the 1990s, mostly reliant on a cryptographic primitive known as Chaumian blinding, provided a currency with a high degree of privacy, but the protocols largely failed to gain traction because of their reliance on a centralized intermediary. In 1998, Wei Dai's b-money(opens in a new tab) became the first proposal to introduce the idea of creating money through solving computational puzzles as well as decentralized consensus, but the proposal was scant on details as to how decentralized consensus could actually be implemented. In 2005, Hal Finney introduced a concept of *reusable proofs of work(opens in a new tab)*, a system which uses ideas from b-money together with Adam Back's computationally difficult Hashcash puzzles to create a concept for a cryptocurrency, but once again fell short of the ideal by relying on trusted computing as a backend. In 2009, a decentralized currency was for the first time implemented in practice by Satoshi Nakamoto, combining established primitives for managing ownership through public key cryptography with a consensus algorithm for keeping track of who owns coins, known as *proof-of-work*. \n \n The mechanism behind proof-of-work was a breakthrough in the space because it simultaneously solved two problems. First, it provided a simple and moderately effective consensus algorithm, allowing nodes in the network to collectively agree on a set of canonical updates to the state of the Bitcoin ledger. Second, it provided a mechanism for allowing free entry into the consensus process, solving the political problem of deciding who gets to influence the consensus, while simultaneously preventing sybil attacks. It does this by substituting a formal barrier to participation, such as the requirement to be registered as a unique entity on a particular list, with an economic barrier - the weight of a single node in the consensus voting process is directly proportional to the computing power that the node brings. Since then, an alternative approach has been proposed called proof-of-stake, calculating the weight of a node as being proportional to its currency holdings and not computational resources; the discussion of the relative merits of the two approaches is beyond the scope of this paper but it should be noted that both approaches can be used to serve as the backbone of a cryptocurrency. (GENESIS)
460 days 14 hrs ago
0x35125...500d53
Null: 0x000...000
IN
0x6dC0...D64811
72,000,000.00
Introduction to Bitcoin and Existing Concepts \n \n History \n \n The concept of decentralized digital currency, as well as alternative applications like property registries, has been around for decades. The anonymous e-cash protocols of the 1980s and the 1990s, mostly reliant on a cryptographic primitive known as Chaumian blinding, provided a currency with a high degree of privacy, but the protocols largely failed to gain traction because of their reliance on a centralized intermediary. In 1998, Wei Dai's b-money(opens in a new tab) became the first proposal to introduce the idea of creating money through solving computational puzzles as well as decentralized consensus, but the proposal was scant on details as to how decentralized consensus could actually be implemented. In 2005, Hal Finney introduced a concept of *reusable proofs of work(opens in a new tab)*, a system which uses ideas from b-money together with Adam Back's computationally difficult Hashcash puzzles to create a concept for a cryptocurrency, but once again fell short of the ideal by relying on trusted computing as a backend. In 2009, a decentralized currency was for the first time implemented in practice by Satoshi Nakamoto, combining established primitives for managing ownership through public key cryptography with a consensus algorithm for keeping track of who owns coins, known as *proof-of-work*. \n \n The mechanism behind proof-of-work was a breakthrough in the space because it simultaneously solved two problems. First, it provided a simple and moderately effective consensus algorithm, allowing nodes in the network to collectively agree on a set of canonical updates to the state of the Bitcoin ledger. Second, it provided a mechanism for allowing free entry into the consensus process, solving the political problem of deciding who gets to influence the consensus, while simultaneously preventing sybil attacks. It does this by substituting a formal barrier to participation, such as the requirement to be registered as a unique entity on a particular list, with an economic barrier - the weight of a single node in the consensus voting process is directly proportional to the computing power that the node brings. Since then, an alternative approach has been proposed called proof-of-stake, calculating the weight of a node as being proportional to its currency holdings and not computational resources; the discussion of the relative merits of the two approaches is beyond the scope of this paper but it should be noted that both approaches can be used to serve as the backbone of a cryptocurrency. (GENESIS)
460 days 14 hrs ago
0xe6427...7edd5a
Reward
Synthetix: Synthetix Network Token
IN
0x6dC0...D64811
826.15
!SNXPool.com ($ sUSD)
460 days 22 hrs ago
0x1be26...93f990
Transfer
0x6dC0...D64811
OUT
GENESIS
1,697.06
Uniswap V2 (UNI-V2)
460 days 22 hrs ago
0xdcb95...25e33b
Mine Genesis Block
Null: 0x000...000
IN
0x6dC0...D64811
1,697.06
Uniswap V2 (UNI-V2)
460 days 22 hrs ago
0xaadf2...06ceeb
Transfer
0x6dC0...D64811
OUT
GENESIS
72,000,000.00
A Next-Generation Smart Contract and Decentralized Application Platform \n \n Satoshi Nakamoto's development of Bitcoin in 2009 has often been hailed as a radical development in money and currency, being the first example of a digital asset which simultaneously has no backing or *intrinsic value(opens in a new tab)* and no centralized issuer or controller. However, another, arguably more important, part of the Bitcoin experiment is the underlying blockchain technology as a tool of distributed consensus, and attention is rapidly starting to shift to this other aspect of Bitcoin. Commonly cited alternative applications of blockchain technology include using on-blockchain digital assets to represent custom currencies and financial instruments (*colored coins(opens in a new tab)*), the ownership of an underlying physical device (*smart property(opens in a new tab)*), non-fungible assets such as domain names (*Namecoin(opens in a new tab)Ü), as well as more complex applications involving having digital assets being directly controlled by a piece of code implementing arbitrary rules (*smart contracts(opens in a new tab)*) or even blockchain-based *decentralized autonomous organizations(opens in a new tab)* (DAOs). What Ethereum intends to provide is a blockchain with a built-in fully fledged Turing-complete programming language that can be used to create *contracts* that can be used to encode arbitrary state transition functions, allowing users to create any of the systems described above, as well as many others that we have not yet imagined, simply by writing up the logic in a few lines of code. (GENESIS)
460 days 22 hrs ago
0xd3d36...b21b64
Null: 0x000...000
IN
0x6dC0...D64811
72,000,000.00
A Next-Generation Smart Contract and Decentralized Application Platform \n \n Satoshi Nakamoto's development of Bitcoin in 2009 has often been hailed as a radical development in money and currency, being the first example of a digital asset which simultaneously has no backing or *intrinsic value(opens in a new tab)* and no centralized issuer or controller. However, another, arguably more important, part of the Bitcoin experiment is the underlying blockchain technology as a tool of distributed consensus, and attention is rapidly starting to shift to this other aspect of Bitcoin. Commonly cited alternative applications of blockchain technology include using on-blockchain digital assets to represent custom currencies and financial instruments (*colored coins(opens in a new tab)*), the ownership of an underlying physical device (*smart property(opens in a new tab)*), non-fungible assets such as domain names (*Namecoin(opens in a new tab)Ü), as well as more complex applications involving having digital assets being directly controlled by a piece of code implementing arbitrary rules (*smart contracts(opens in a new tab)*) or even blockchain-based *decentralized autonomous organizations(opens in a new tab)* (DAOs). What Ethereum intends to provide is a blockchain with a built-in fully fledged Turing-complete programming language that can be used to create *contracts* that can be used to encode arbitrary state transition functions, allowing users to create any of the systems described above, as well as many others that we have not yet imagined, simply by writing up the logic in a few lines of code. (GENESIS)
461 days 7 hrs ago
0x4532d...359ddc
Transfer
0x6dC0...D64811
OUT
GENESIS
758.95
Uniswap V2 (UNI-V2)
461 days 8 hrs ago
0x01bc1...b38e5d
Mine Genesis Block
Null: 0x000...000
IN
0x6dC0...D64811
758.95
Uniswap V2 (UNI-V2)
461 days 8 hrs ago
0x07205...a37536
Transfer
0x6dC0...D64811
OUT
GENESIS
72,000,000.00
A Next-Generation Smart Contract and Decentralized Application Platform \n \n Satoshi Nakamoto's development of Bitcoin in 2009 has often been hailed as a radical development in money and currency, being the first example of a digital asset which simultaneously has no backing or *intrinsic value(opens in a new tab)* and no centralized issuer or controller. However, another, arguably more important, part of the Bitcoin experiment is the underlying blockchain technology as a tool of distributed consensus, and attention is rapidly starting to shift to this other aspect of Bitcoin. Commonly cited alternative applications of blockchain technology include using on-blockchain digital assets to represent custom currencies and financial instruments (*colored coins(opens in a new tab)*), the ownership of an underlying physical device (*smart property(opens in a new tab)*), non-fungible assets such as domain names (*Namecoin(opens in a new tab)*), as well as more complex applications involving having digital assets being directly controlled by a piece of code implementing arbitrary rules (*smart contracts(opens in a new tab)*) or even blockchain-based *decentralized autonomous organizations(opens in a new tab)* (DAOs). What Ethereum intends to provide is a blockchain with a built-in fully fledged Turing-complete programming language that can be used to create *contracts* that can be used to encode arbitrary state transition functions, allowing users to create any of the systems described above, as well as many others that we have not yet imagined, simply by writing up the logic in a few lines of code. \n \n Introduction to Bitcoin and Existing Concepts \n \n History \n \n The concept of decentralized digital currency, as well as alternative applications like property registries, has been around for decades. The anonymous e-cash protocols of the 1980s and the 1990s, mostly reliant on a cryptographic primitive known as Chaumian blinding, provided a currency with a high degree of privacy, but the protocols largely failed to gain traction because of their reliance on a centralized intermediary. In 1998, Wei Dai's b-money(opens in a new tab) became the first proposal to introduce the idea of creating money through solving computational puzzles as well as decentralized consensus, but the proposal was scant on details as to how decentralized consensus could actually be implemented. In 2005, Hal Finney introduced a concept of *reusable proofs of work(opens in a new tab)*, a system which uses ideas from b-money together with Adam Back's computationally difficult Hashcash puzzles to create a concept for a cryptocurrency, but once again fell short of the ideal by relying on trusted computing as a backend. In 2009, a decentralized currency was for the first time implemented in practice by Satoshi Nakamoto, combining established primitives for managing ownership through public key cryptography with a consensus algorithm for keeping track of who owns coins, known as *proof-of-work*. \n \n The mechanism behind proof-of-work was a breakthrough in the space because it simultaneously solved two problems. First, it provided a simple and moderately effective consensus algorithm, allowing nodes in the network to collectively agree on a set of canonical updates to the state of the Bitcoin ledger. Second, it provided a mechanism for allowing free entry into the consensus process, solving the political problem of deciding who gets to influence the consensus, while simultaneously preventing sybil attacks. It does this by substituting a formal barrier to participation, such as the requirement to be registered as a unique entity on a particular list, with an economic barrier - the weight of a single node in the consensus voting process is directly proportional to the computing power that the node brings. Since then, an alternative approach has been proposed called proof-of-stake, calculating the weight of a node as being proportional to its currency holdings and not computational resources; the discussion of the relative merits of the two approaches is beyond the scope of this paper but it should be noted that both approaches can be used to serve as the backbone of a cryptocurrency. \n \n Bitcoin As A State Transition System \n \n From a technical standpoint, the ledger of a cryptocurrency such as Bitcoin can be thought of as a state transition system, where there is a *state* consisting of the ownership status of all existing bitcoins and a *state transition function* that takes a state and a transaction and outputs a new state which is the result. In a standard banking system, for example, the state is a balance sheet, a transaction is a request to move $X from A to B, and the state transition function reduces the value in A's account by $X and increases the value in B's account by $X. If A's account has less than $X in the first place, the state transition function returns an error. Hence, one can formally define: \n The *state* in Bitcoin is the collection of all coins (technically, Üunspent transaction outputs* or UTXO) that have been minted and not yet spent, with each UTXO having a denomination and an owner (defined by a 20-byte address which is essentially a cryptographic public keyfn1). A transaction contains one or more inputs, with each input containing a reference to an existing UTXO and a cryptographic signature produced by the private key associated with the owner's address, and one or more outputs, with each output containing a new UTXO to be added to the state. \n The state transition function APPLY(S,TX) -> S' can be defined roughly as follows: For each input in TX: If the referenced UTXO is not in S, return an error. If the provided signature does not match the owner of the UTXO, return an error. If the sum of the denominations of all input UTXO is less than the sum of the denominations of all output UTXO, return an error. Return S with all input UTXO removed and all output UTXO added. \n The first half of the first step prevents transaction senders from spending coins that do not exist, the second half of the first step prevents transaction senders from spending other people's coins, and the second step enforces conservation of value. In order to use this for payment, the protocol is as follows. Suppose Alice wants to send 11.7 BTC to Bob. First, Alice will look for a set of available UTXO that she owns that totals up to at least 11.7 BTC. Realistically, Alice will not be able to get exactly 11.7 BTC; say that the smallest she can get is 6+4+2=12. She then creates a transaction with those three inputs and two outputs. The first output will be 11.7 BTC with Bob's address as its owner, and the second output will be the remaining 0.3 BTC *change*, with the owner being Alice herself \n (GENESIS)
461 days 8 hrs ago
0xc6c9d...e37085
Null: 0x000...000
IN
0x6dC0...D64811
72,000,000.00
A Next-Generation Smart Contract and Decentralized Application Platform \n \n Satoshi Nakamoto's development of Bitcoin in 2009 has often been hailed as a radical development in money and currency, being the first example of a digital asset which simultaneously has no backing or *intrinsic value(opens in a new tab)* and no centralized issuer or controller. However, another, arguably more important, part of the Bitcoin experiment is the underlying blockchain technology as a tool of distributed consensus, and attention is rapidly starting to shift to this other aspect of Bitcoin. Commonly cited alternative applications of blockchain technology include using on-blockchain digital assets to represent custom currencies and financial instruments (*colored coins(opens in a new tab)*), the ownership of an underlying physical device (*smart property(opens in a new tab)*), non-fungible assets such as domain names (*Namecoin(opens in a new tab)*), as well as more complex applications involving having digital assets being directly controlled by a piece of code implementing arbitrary rules (*smart contracts(opens in a new tab)*) or even blockchain-based *decentralized autonomous organizations(opens in a new tab)* (DAOs). What Ethereum intends to provide is a blockchain with a built-in fully fledged Turing-complete programming language that can be used to create *contracts* that can be used to encode arbitrary state transition functions, allowing users to create any of the systems described above, as well as many others that we have not yet imagined, simply by writing up the logic in a few lines of code. \n \n Introduction to Bitcoin and Existing Concepts \n \n History \n \n The concept of decentralized digital currency, as well as alternative applications like property registries, has been around for decades. The anonymous e-cash protocols of the 1980s and the 1990s, mostly reliant on a cryptographic primitive known as Chaumian blinding, provided a currency with a high degree of privacy, but the protocols largely failed to gain traction because of their reliance on a centralized intermediary. In 1998, Wei Dai's b-money(opens in a new tab) became the first proposal to introduce the idea of creating money through solving computational puzzles as well as decentralized consensus, but the proposal was scant on details as to how decentralized consensus could actually be implemented. In 2005, Hal Finney introduced a concept of *reusable proofs of work(opens in a new tab)*, a system which uses ideas from b-money together with Adam Back's computationally difficult Hashcash puzzles to create a concept for a cryptocurrency, but once again fell short of the ideal by relying on trusted computing as a backend. In 2009, a decentralized currency was for the first time implemented in practice by Satoshi Nakamoto, combining established primitives for managing ownership through public key cryptography with a consensus algorithm for keeping track of who owns coins, known as *proof-of-work*. \n \n The mechanism behind proof-of-work was a breakthrough in the space because it simultaneously solved two problems. First, it provided a simple and moderately effective consensus algorithm, allowing nodes in the network to collectively agree on a set of canonical updates to the state of the Bitcoin ledger. Second, it provided a mechanism for allowing free entry into the consensus process, solving the political problem of deciding who gets to influence the consensus, while simultaneously preventing sybil attacks. It does this by substituting a formal barrier to participation, such as the requirement to be registered as a unique entity on a particular list, with an economic barrier - the weight of a single node in the consensus voting process is directly proportional to the computing power that the node brings. Since then, an alternative approach has been proposed called proof-of-stake, calculating the weight of a node as being proportional to its currency holdings and not computational resources; the discussion of the relative merits of the two approaches is beyond the scope of this paper but it should be noted that both approaches can be used to serve as the backbone of a cryptocurrency. \n \n Bitcoin As A State Transition System \n \n From a technical standpoint, the ledger of a cryptocurrency such as Bitcoin can be thought of as a state transition system, where there is a *state* consisting of the ownership status of all existing bitcoins and a *state transition function* that takes a state and a transaction and outputs a new state which is the result. In a standard banking system, for example, the state is a balance sheet, a transaction is a request to move $X from A to B, and the state transition function reduces the value in A's account by $X and increases the value in B's account by $X. If A's account has less than $X in the first place, the state transition function returns an error. Hence, one can formally define: \n The *state* in Bitcoin is the collection of all coins (technically, Üunspent transaction outputs* or UTXO) that have been minted and not yet spent, with each UTXO having a denomination and an owner (defined by a 20-byte address which is essentially a cryptographic public keyfn1). A transaction contains one or more inputs, with each input containing a reference to an existing UTXO and a cryptographic signature produced by the private key associated with the owner's address, and one or more outputs, with each output containing a new UTXO to be added to the state. \n The state transition function APPLY(S,TX) -> S' can be defined roughly as follows: For each input in TX: If the referenced UTXO is not in S, return an error. If the provided signature does not match the owner of the UTXO, return an error. If the sum of the denominations of all input UTXO is less than the sum of the denominations of all output UTXO, return an error. Return S with all input UTXO removed and all output UTXO added. \n The first half of the first step prevents transaction senders from spending coins that do not exist, the second half of the first step prevents transaction senders from spending other people's coins, and the second step enforces conservation of value. In order to use this for payment, the protocol is as follows. Suppose Alice wants to send 11.7 BTC to Bob. First, Alice will look for a set of available UTXO that she owns that totals up to at least 11.7 BTC. Realistically, Alice will not be able to get exactly 11.7 BTC; say that the smallest she can get is 6+4+2=12. She then creates a transaction with those three inputs and two outputs. The first output will be 11.7 BTC with Bob's address as its owner, and the second output will be the remaining 0.3 BTC *change*, with the owner being Alice herself \n (GENESIS)
461 days 8 hrs ago
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