Quid faciamus stipitem?

Tota hominum historia est continuus processus tollendi vincula et novas etiam validiores creando. (Anonymous author)

Multas clausulas inceptas dividendo (Bitshares, Hyperledger, Exonum, Ethereum, Bitcoin, etc.), intelligo ex technica parte, omnia iisdem principiis inaedificata. Claustra domorum similia sunt, quae, licet omni varietate consiliorum, decoris ac causarum, fundamentum habent, parietes, tectum, fenestras, ostia, quae certo modo inter se connexa sunt. Et si intelligas principia fundamentalia de consilio aedificandi et proprietates materiae cognoscendi, tunc propositum particularis domus poteris determinare. Nunc, res cum impedimento orta est quod omnes audiverunt, sed pauci architecturam ac principia operandi intelligunt. Ideo est error cur et quomodo sensus utendi blockchain technologiae.

In hoc articulo proprietates et principia communia omnibus impedimentis resolvemus. Deinde inspiciamus quaestiones quae solvi possunt utendo claustro et ad materiam roborandam, parvum sed verum impedimentum aedificemus in situ virtuali nostro!

Itaque meminerimus quae in initio clausulae problemata solvantur.

Pro certo habeo plures dicere de database distributo, decentralized, publico et immutabili. Sed quorsum haec necessaria?

Malo discere quamlibet technologiam signis legendis incipere, cum omnes articuli et libri de re sub studio in illis fundantur. Sed nunc non sunt blockchain signa; ISO modo creatus est committees ad earum progressum. In statu, unumquodque negotium publicum claustrum proprium documentum chartaceum albae habet, quod essentialiter specificatio technica est. Prima palam nota impedimentum consilii est reticulum BitCoin. Vade ad rutrum reticuli et quaerere ubi omnes coeperunt.

Blockchain provocare

Negotium igitur, quod impedimentum solvuntur in retis BitCoin auctoris, est facere creditam translationem bonorum digitalium (res) in ambitu non credito sine intermediis. For example, in bitcoin network, bitcoin digitale dignissim esse molestie nummi. Et omnes solutiones technicae BitCoin et alii impedimenta descendunt ad hanc quaestionem solvendam.

Problems quod blockchain solvit

Pone quandam ordinationem nummariam dicit eam retis circum orbem condidisse, cuius ope pecuniam cuilibet homini transferre potest. Credis eam? Si haec organizationis Visa est vel MasterCard, verisimile id credes, sed si, relative loquendo, AnonymousWorldMoney, probabiliter non poteris. Quare? Sed quia optime novimus quomodo systemata a privatis societatibus, ad quos usus, et quid in hunc finem deducantur, probe novimus. Propius inspiciamus problemata talium systematum et quomodo technologiarum impedimento uti solvi possint.

Dicamus in conditionali AnonymousWorldMoney ministrare cum databases esse, et bonum esse si plures ex eis in diversis notitiis centris sunt. Cum mittente pecuniam transfert, negotium relatus est, quae omnibus servientibus replicatur et pecunia ad recipientem pervenit.

In ideali mundo haec schema magna operatur, at in nostro sequenti problemata oriuntur:

1. Problema cognoscendi participes ex una parte et necessitatem anonymiae transactionum ex altera. Illae. pecuniam ad certum recipiens transferre debes et ita ut nemo sciat de hac re nisi participes facti. Ripae rationem habent numeri et chartae argentariae cum individuo sive legali ente specifico coniunctae, et secretio argentaria informationes transactionis tuetur. Et quis spondet AnonymousWorldmoney conditionalem non uti personalis notitia et transactione notitia ad suos usus?
2. Quomodo fac ut ille recipiens quantitatem, quae ad eum translata fuit? Relative loquens mittens $100 transfertur, et recipiens $10. Missor venit ad officium AnonymousWorldMoney cum acceptis suis, et clericus suam versionem ostendit, ubi scriptum est mittentem tantum $10.
3. Quaestio de ambitu trepidi, exempli gratia, MALITIA vocatur duplex impendium. Improbus particeps stateram suam pluries expendere potest donec solutio omnibus servientibus replicatur. CAPnullus utique cassetur, et consensus ultimo obtinebitur, sed quis pecuniam pro servitiis vel bonis provisis non recipiet. Si igitur nulla est perfecta fiducia in solutione dispositionis vel negotiorum participantium, necesse est ut retis non fiducia, sed cryptographia fundatur.
4. Conditionalis AnonymousWorldMoney finitum numerum ministrantium habet, qui per ignorantiam vel propter malitiosam intentionem fieri potest.
5. AnonymousWorldMoney suam commissionem tangibilem habebit.
6. Possibilitas imperii. In operatione BitCoin evenit ut homines non solum nummos ad se invicem transferre velint, sed etiam varias condiciones ad rem gerendam, programmata missionum operandi, actiones secundum condiciones sponte praestare, etc.

Quomodo blockchain solvit haec problemata

1. Lepidium sativum participantium exercetur in duobus clavibus: privatis et publicis, et algorithmus digitalis singulariter agnoscit mittente et recipientem, relictis identitatibus anonymis.
2. Acta in caudices colliguntur, fasciae stipis computatae sunt et in proximum scandalum scriptae. Haec series recordationis in cuneis trahit impedimentum technologiae nomen suum dat, et etiam impossibilem facit ut inobservabiliter mutetur / deleat cuneos vel singulas res a caudices. Ita, si negotium in claustro comprehenditur, certo potes notitias eius immutata manere.
3. Dolus duplex impendit impeditur perveniens consensus retis in quo notitia valida considerandi et quae abiicienda est. In retis BitCoin consensus fit probatione operis (PoW).
4. Fiducia reticuli eo consequitur quod impedimentum publicum est, ubi quisque particeps nodi sua currere potest, totum exemplum impedimenti accipiet et praeterea independenter a rectitudine transactions reprimere incipiunt. Animadvertendum est quod hodierni impedimenta efficere possunt non solum publicas (aperta) sed etiam impedimenta privata, ac usus consiliorum coniunctorum.
5. Claustrum non omnino commissiones tollendas, quia... tu homines qui retia sustinent reddere debes, sed in clausula opus commissionis ita evidenter probatur ut de eius necessitate dubitari non possit.
6. Clausiones modernae facultatem habent ad efficiendum logicam negotiationem, quae in impedimento Smert Contractus appellatur. Logica contractuum callidiorum in variis linguis summus gradus impletur.

Deinde fusius has solutiones expendemus.

Blockchain architectura

Blockchain Components

Quisque particeps nodi suum mittere potest cum pleno exemplari claustri (nodi plenae). Pleni nodi qui transactiones in claustro vocantur consensus lymphaticorum (testis) vel fossores. Nodi pleni, qui rectitudinem rerum gestarum solum coercere dicuntur audit lymphaticorum (audit). Lux clients (levis clientes) exemplaria plena claustri non reponunt, sed inter se occurrunt cum retiacula plena nodis utentes.
Plerique utentes levibus clientibus vel reticulis interretialibus ad transactiones adhibendas utuntur. Nodi omnes inter se connectuntur. Cum hoc elementorum statuto, architectura retis firmior fit:

Transactio vitae exolvuntur

Intueamur transactionem lifecycli et confringe eam per partes:

Claustrum technologiae

In solutionibus technicis eorumque nexus inter se accuratius habitemus.

Lepidium sativum

Omnis blockchain transactionis digitally signari debet. Ideo ad rem perficiendam quilibet particeps debet habere clavem par: privatum / publicum. Aliquando par clavium vidulus dicitur, quia claves unice coniunguntur cum unica inscriptione digitali et statera participantis. Re vera, claves et inscriptiones sunt sicut chordae numerorum in diversis systematibus numerorum. Exempla clavium et inscriptionum crumenae:

Private key: 0a78194a8a893b8baac7c09b6a4a4b4b161b2f80a126cbb79bde231a4567420f
Public key: 0579b478952214d7cddac32ac9dc522c821a4489bc10aac3a81b9d1cd7a92e57ba
Address: 0x3814JnJpGnt5tB2GD1qfKP709W3KbRdfb27V

Ad signaturam digitalem in clausulis creare, algorithmus in curvis ellipticis fundatur: Curva Elliptica Digital Signatura Algorithmus (ECDSA). Ad hoc opus, clavis privata (256-bit numerus) passim sumi solet. Numerus optionum clavis clavis 2 est ad potentiam 256, ut loqui possumus de impossibilitate practica valorum claves privatarum priorum.

Deinde, clavis publicus obtinetur ex privato, multiplicando valorem ejus a coordinatis puncti in curva elliptico collocati, inde in coordinatis puncti novi in ​​eadem curva. Haec actio efficit ut clavem par clavem obtineas ad transactiones signandas aptas digitally. Inscriptio denique manticae unice e clavis publica ducta est.

Multi articuli cum singulis in cryptographia utuntur in clausura, exempli gratia: BitCoin in nuce - Cryptography

Clavis privata stricte secreta esse debet et secure custodiri. Clavis publica omnibus nota est. Si clavis privatus amittitur, aditus ad res (denarios) restitui non potest et pecunia in perpetuum amittetur. Propterea munus clavium privatarum secure condiendi maxime pertinet, quia Hoc argentarium non est ubi semper cum diplomate tuo venire potes et rationem tuam restitue. Est omnis industria ad productionem sic dictae cryptae frigidae perae, similes fulgoribus eicit;

vel certioribus modis uti potes, exempli gratia, valorem clavis privatis in signis impressis;

Transactions

Plura de transactione structura inveniri possunt in articulo BitCoin in nuce - transactionis. Praestat nobis intelligere singulas transactiones saltem sequentes notitias habere:

From: 0x48C89c341C5960Ca2Bf3732D6D8a0F4f89Cc4368 - цифровой адрес отправителя
To: 0x367adb7894334678b90аfe7882a5b06f7fbc783a - цифровой адрес получателя
Value: 0.0001 - сумма транзакции
Transaction Hash: 0x617ede331e8a99f46a363b32b239542bb4006e4fa9a2727a6636ffe3eb095cef - хэш транзакции

Deinceps transactiones cum clavis privatis et emissis signatur (vide singula in operatione protocolli BitCoin in nuce Protocol) omnibus nodis in claustro qui transactions ad validitatem reprimunt. Rei verificationem algorithmus est non levis et includit Duo dozen gradibus.

Transactio caudices

Post validitatem transactionum iniectae, nodi format caudices ab eis. Praeter transactions, Nullam prioris scandali et plures (Nonce counter) scripta sunt in scandalum, et Nullam scandali currentis computatur utendo algorithmo SHA-256. Nullam intricatas condiciones instituisse debet. Exempli gratia, in retis BitCoin difficultas Nullam automatice mutatur singulis 2 septimanis secundum potentiam retis ita ut stipes semel singulis 10 minutis generatur. Incomplexitas hac condicione determinatur: Nullam inventa minus esse debet quam numerus praefinitus. Si haec conditio non occurrit, 1 additur Nonae, et repetitur opus calculandi Nullam. Nullam eligere, campus Nonce adhibetur, quia Haec sola notitia in stipite mutari potest, cetera immutata manere debent. Nullam validam certos ziphos ducendi habere debet, ut unum e realibus cursoribus;

000000000000000000000bf03212e7dd1176f52f816fa395fc9b93c44bc11f91

Feliciter Nullam invenire probationem operis facti (Proof-of-Opus, PoW) pro retiacula Bitcoin vel Ethereum. Hases inveniendi processus fodienda appellatur, metalla auri similis. Nomen processus essentiam satis accurate definit, quoniam Simplex quaesitio optionum est, et si quis Nullam idoneam invenit, haec est vere fortuna. Simile est invenire verum aurum MASSA in tons vasti saxi. Merces clausus nunc est 12.5 BTC et si eam multiplicaveris per rate of $3900 BitCoin current, plus quam chiliogramma auri puri possides. Est aliquid pro!

Post hash feliciter inveniendo, scandalum et Nullam ipsum inventa scripta sunt ad impedimentum sicut stipes proximus. Plura de structura caudices in articulo inveniri possunt BitCoin in nuce-Blockchainet infra figuratum est simplicior;

Claustrum incipit cum trunco ​​quod nondum Nullam prioris stipes habet. Unus est talis clausus in claustro et proprium nomen Genesis clausus habet. Reliquae caudices eandem structuram habent et tantum in numero rerum differunt. Realis transactions et caudices currently creantur in BitCoin vel Ethereum spectari possunt in Explorer obstructionum.

Magnitudo clausorum in BitCoin ad 1MB contrahitur et cum minima copia notitiarum in transactione circiter 200 bytes, maximus numerus negotiorum in stipite circiter 6000 esse potest. Hinc obiter sequitur BitCoin observantiam, quam omnes rident: truncus generatur semel fere singulis 10 minutis * 60 secundis = 600 secundis, quae dat formalem observantiam circiter 10 TPS. Quamvis re vera, haec non est productiva, sed de industria algorithmus laboris impletur. In Ethereo, propter contentionem, simpliciter fecerunt scandalum generationis temporis 15 secundis. et fructibus formaliter volaverat. Ideo in impedimentis qui PW ut consensus utuntur, nullum sensum ad perficiendum omnino comparare, quia directe pendet a complexitate calculi, qui cuivis pretii assignari potest.

Furculas

Quid accidit si, exempli gratia, plures nodos invenerunt ligaturae obviae multiplicitati condicionum, sed in pretio diversae sunt (id est, ad diversos consensus accesserunt) et ad stipites clausos scripserunt? Videamus quomodo impedimentum contra hanc condicionem tuetur. In hoc casu, ut aiunt, furca occurrit, et impedimentum duas versiones catenae habet;

Quid deinde? Deinde retis pars N+2 ab una catena, et pars ab alia incipit laborare;

Una ex his caudices prior invenietur et ad impedimentum mittetur, et tunc, secundum regulas, impedimentum erit ad longiorem catenam mutandam et omnes res ab alio scandalo destruet;

Eodem tempore evenire potest, cum particeps negotii fuit in una tantum caudices furcae, quae cassatae sunt. Ideo ut scias rem desideratam in impedimento commemorari, generalis commendatio est - antequam negotii confidat, expectare debes donec pauci alii ad stipitem adiciantur. Commendationes quot caudices exspectant, variae impedimenta variantur. Exempli gratia, retiacula BitCoin minimum est 2 cuneos, maximum 6 est.

Eadem pictura cum uncinis clausuris in oppugnatione sic dicta 51% observabitur - haec est, cum fossorum globus catellam emittere temptat jocus clausus, quaerens catenam rescindere cum suis fraudulentis negotiis. Etsi nunc, pro fraude, utilius est tuam potestatem in sincera fodienda consumere.

Consensus

Ad truncum in clausula adnotare, retis consensum attingere debet. Meminerimus munus consequendi consensus in retiacula communicationis computatrum. Proponitur quaestio de munere ducum byzantinorum BFT (Constantine culpa tolerantia). Omissis ornatior descriptione problematum exercitus byzantini, quaestio hoc modo enunciari potest: quomodo nodi reticuli ad communem exitum perveniunt, si quidam nodi retis eas consulto possunt convertere. Existens algorithms ad problema solvendum BFT ostendunt reticulum recte operari posse si fraudes 1/3 minus sint. Cur consensus BFT ad BitCoin network applicatus non est? Cur necesse fuit uti POW? Causae plures sunt:

• BFT bene operatur cum parva nodorum serie fixa, sed in publico impedimento numerus nodi vagus est et praeterea nodi passim verti possunt.
• Necesse est homines movere ad nodos clausus deducendi. Ad hoc homines remunerari debent. In BFT nihil est formaliter praemium pro accipiendo, sed quod praemium est in POW, omnibus patet in gradu intuitivo: nam electricitas consumpta est per processum in processu in inveniendi stipitem Nullam.

Praeter POW, plures aliae sunt consensus quae in impedimentis recentioribus adhibentur, exempli gratia:

• PoS (Proof-of-Stake) - in scandalum Hyperledger
• DPoS (Delegatus Probatio-of-Stake) - in blockchain BitShares
• Modificationes BFT: SBFT (facilius BFT) et PBFT (Practical BFT), exempli gratia in blockchain Exonum

Paulum in consensu PoS habitemus, quia... Est PoS eiusque varietates, quae in impedimentis privatis latissime disseminatae sunt. Cur privatim? Ex altera parte, characteres PoS melius cum POW comparantur, quia Ad consensum consequendum, facultates computandi minus necessariae sunt, quae celeritas instrumenti scribendi notitias impedimento auget. At contra, PoS plus fraudis occasiones habet, ut hoc modo corrumpant, omnes participes impedimenti sciri debent.

PoS consensus fundatur in electione nodi quae scribere potest scandalum cum transactionibus ad blockchain secundum quantitatem pecuniarum in compoto, vel potius, non in compoto, sed in collaterali, i.e. Quo plus pecuniae pignus habes, eo magis reticulum nodi eliget ad scandalum scribendum. depositum non reddetur, si impedimentum invalidum est. Hoc contra dolum praesidium praebet. PoS variationes sequentes sunt:

• Consensus delegatus PoS (DPoS) participantes dividit in "votores" et "validatores". Nummi detentores (participes suffragii) potestatem suam delegant ad cognoscendum et res gestas in claustro aliis participantibus. Quapropter omnes opus computatorium agunt validatores ac praemium pro eo accipiunt, et praesentia suffragiorum participantium probitatem validatorum praestat, quia. aliquando mutari possunt.
• LPoS (Lased Probatio-of-Stake) consensus permittit te pecunias tuas aliis nodi locare ut meliorem occasionem habeant caudices confirmandi. Quod. Potes commissionem de rebus agendis recipere sine participatione actualis transactionis verificationis et fodiendi.

Sunt plures alii consensus qui nondum late usi sunt, eas hic pro informatione modo enumerabo, et consideratio consensus algorithmorum ipsarum reperiri potest, exempli gratia, in articulo: Consensus Algorithmus in Blockchain.

• Poetae (Proof-of-Elapsed Time)
• PoC (Proof-of-Capacitas)
• PoB (Proof-of Burn)
• PoWeight (Proof-of-pondus)
• PoA (Proof-of-Actio) - POW + PoS
• PoI (Proof-of-Importans)

Reliability et instruere exempla impedimentorum

Publica blockchain

constantiam Public vel alio nomine Permissionless blockchain Hoc obtinetur permittens aliquem informationem ac visum connectere vel etiam proprium nodi coniungere, ac fiducia in consensu POW aedificata.

Privata blockchain

Secretum aut Privata Permissionis blockchain. In his impedimentis, tantum quidam coetus participantium (organizationes vel homines) accessum habent ad informationem. Tales impedimenta constituuntur ab Institutis cum meta augendi altioris utilitatis vel efficientiae. Eorum fides in communibus metis participantium et consensus algorithmorum PoS et BFT conservatur.

Claustrum Consortium

ibi Consortium aut Publica Permissionis blockchain. Hi impedimenta sunt quae quis ad visum coniungere potest, participem autem informationes addere vel nodi modo cum licentia aliorum participantium coniungere potest. Tales impedimenta constituuntur a Institutis ut fiducia augeatur ex parte clientium vel sumentium productorum vel totius societatis. Fiducia hic etiam obtinetur praesentia fiduciae inter participes eiusdemque PoS et BFT consensus algorithms.

Contractus dolor

Claustras effectas post BitCoin habent, ad unum gradum vel alium, facultatem ad exsequendam contractuum captiosam. Per se, dolor contractus est transactionis in quo codice programmatis ad executionem ponitur. Captiosus contractus in network Ethereum in EVM (Ethereum Virtualis Machina). Ut gravius ​​contractum exsequi incipias, ab alio negotio explicite deduci debet vel condiciones executionis occurrere debent. Eventus exsecutionis contractus captiosus etiam in impedimento scribendus erit. Accepto notitia extra impedimentum fieri potest, sed perquam limitata.

Quodnam negotium logice perfici potest utens acri contractu? Revera, non multum est, exempli gratia, condiciones utentes notitia ex impedimento, mutatis dominis bonorum digitalium secundum has condiciones, notas notare in repositione permanenti intra claustrum. Logica perducitur peculiari gradu linguae soliditatis.

Exemplar classicum functionis quae in usu contractuum acri impletur est editae notarum pro ICOs. Exempli causa, acri contractu effectum sum ad AlexToken modicis 500 edendam. By link in Etherscan est

source code of the smart contract in the Solidity language

pragma solidity ^0.4.23;
library SafeMath {
/**
* @dev Multiplies two numbers, throws on overflow.
**/
function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
if (a == 0) {
return 0;
}
c = a * b;
assert(c / a == b);
return c;
}
/**
* @dev Integer division of two numbers, truncating the quotient.
**/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
// assert(b > 0); // Solidity automatically throws when dividing by 0
/**
* @title SafeMath
* @dev Math operations with safety checks that throw on error
*/
// uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return a / b;
}
/**
* @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
**/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
assert(b <= a);
return a - b;
}
/**
* @dev Adds two numbers, throws on overflow.
**/
function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
c = a + b;
assert(c >= a);
return c;
}
}
/**
* @title Ownable
* @dev The Ownable contract has an owner address, and provides basic authorization control
* functions, this simplifies the implementation of "user permissions".
**/
contract Ownable {
address public owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev The Ownable constructor sets the original `owner` of the contract to the sender account.
**/
constructor() public {
owner = msg.sender;
}
/**
* @dev Throws if called by any account other than the owner.
**/
modifier onlyOwner() {
require(msg.sender == owner);
_;
}
/**
* @dev Allows the current owner to transfer control of the contract to a newOwner.
* @param newOwner The address to transfer ownership to.
**/
function transferOwnership(address newOwner) public onlyOwner {
require(newOwner != address(0));
emit OwnershipTransferred(owner, newOwner);
owner = newOwner;
}
}
/**
* @title ERC20Basic interface
* @dev Basic ERC20 interface
**/
contract ERC20Basic {
function totalSupply() public view returns (uint256);
function balanceOf(address who) public view returns (uint256);
function transfer(address to, uint256 value) public returns (bool);
event Transfer(address indexed from, address indexed to, uint256 value);
}
/**
* @title ERC20 interface
* @dev see https://github.com/ethereum/EIPs/issues/20
**/
contract ERC20 is ERC20Basic {
function allowance(address owner, address spender) public view returns (uint256);
function transferFrom(address from, address to, uint256 value) public returns (bool);
function approve(address spender, uint256 value) public returns (bool);
event Approval(address indexed owner, address indexed spender, uint256 value);
}
/**
* @title Basic token
* @dev Basic version of StandardToken, with no allowances.
**/
contract BasicToken is ERC20Basic {
using SafeMath for uint256;
mapping(address => uint256) balances;
uint256 totalSupply_;
/**
* @dev total number of tokens in existence
**/
function totalSupply() public view returns (uint256) {
return totalSupply_;
}
/**
* @dev transfer token for a specified address
* @param _to The address to transfer to.
* @param _value The amount to be transferred.
**/
function transfer(address _to, uint256 _value) public returns (bool) {
require(_to != address(0));
require(_value <= balances[msg.sender]);
balances[msg.sender] = balances[msg.sender].sub(_value);
balances[_to] = balances[_to].add(_value);
emit Transfer(msg.sender, _to, _value);
return true;
}
/**
* @dev Gets the balance of the specified address.
* @param _owner The address to query the the balance of.
* @return An uint256 representing the amount owned by the passed address.
**/
function balanceOf(address _owner) public view returns (uint256) {
return balances[_owner];
}
}
contract StandardToken is ERC20, BasicToken {
mapping (address => mapping (address => uint256)) internal allowed;
/**
* @dev Transfer tokens from one address to another
* @param _from address The address which you want to send tokens from
* @param _to address The address which you want to transfer to
* @param _value uint256 the amount of tokens to be transferred
**/
function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
require(_to != address(0));
require(_value <= balances[_from]);
require(_value <= allowed[_from][msg.sender]);
balances[_from] = balances[_from].sub(_value);
balances[_to] = balances[_to].add(_value);
allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
emit Transfer(_from, _to, _value);
return true;
}
/**
* @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
*
* Beware that changing an allowance with this method brings the risk that someone may use both the old
* and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
* race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
* @param _spender The address which will spend the funds.
* @param _value The amount of tokens to be spent.
**/
function approve(address _spender, uint256 _value) public returns (bool) {
allowed[msg.sender][_spender] = _value;
emit Approval(msg.sender, _spender, _value);
return true;
}
/**
* @dev Function to check the amount of tokens that an owner allowed to a spender.
* @param _owner address The address which owns the funds.
* @param _spender address The address which will spend the funds.
* @return A uint256 specifying the amount of tokens still available for the spender.
**/
function allowance(address _owner, address _spender) public view returns (uint256) {
return allowed[_owner][_spender];
}
/**
* @dev Increase the amount of tokens that an owner allowed to a spender.
*
* approve should be called when allowed[_spender] == 0. To increment
* allowed value is better to use this function to avoid 2 calls (and wait until
* the first transaction is mined)
* From MonolithDAO Token.sol
* @param _spender The address which will spend the funds.
* @param _addedValue The amount of tokens to increase the allowance by.
**/
function increaseApproval(address _spender, uint _addedValue) public returns (bool) {
allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
return true;
}
/**
* @dev Decrease the amount of tokens that an owner allowed to a spender.
*
* approve should be called when allowed[_spender] == 0. To decrement
* allowed value is better to use this function to avoid 2 calls (and wait until
* the first transaction is mined)
* From MonolithDAO Token.sol
* @param _spender The address which will spend the funds.
* @param _subtractedValue The amount of tokens to decrease the allowance by.
**/
function decreaseApproval(address _spender, uint _subtractedValue) public returns (bool) {
uint oldValue = allowed[msg.sender][_spender];
if (_subtractedValue > oldValue) {
allowed[msg.sender][_spender] = 0;
} else {
allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
}
emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
return true;
}
}
/**
* @title Configurable
* @dev Configurable varriables of the contract
**/
contract Configurable {
uint256 public constant cap = 1000000000*10**18;
uint256 public constant basePrice = 100*10**18; // tokens per 1 ether
uint256 public tokensSold = 0;
uint256 public constant tokenReserve = 500000000*10**18;
uint256 public remainingTokens = 0;
}
/**
* @title CrowdsaleToken 
* @dev Contract to preform crowd sale with token
**/
contract CrowdsaleToken is StandardToken, Configurable, Ownable {
/**
* @dev enum of current crowd sale state
**/
enum Stages {
none,
icoStart, 
icoEnd
}
Stages currentStage;
/**
* @dev constructor of CrowdsaleToken
**/
constructor() public {
currentStage = Stages.none;
balances[owner] = balances[owner].add(tokenReserve);
totalSupply_ = totalSupply_.add(tokenReserve);
remainingTokens = cap;
emit Transfer(address(this), owner, tokenReserve);
}
/**
* @dev fallback function to send ether to for Crowd sale
**/
function () public payable {
require(currentStage == Stages.icoStart);
require(msg.value > 0);
require(remainingTokens > 0);
uint256 weiAmount = msg.value; // Calculate tokens to sell
uint256 tokens = weiAmount.mul(basePrice).div(1 ether);
uint256 returnWei = 0;
if(tokensSold.add(tokens) > cap){
uint256 newTokens = cap.sub(tokensSold);
uint256 newWei = newTokens.div(basePrice).mul(1 ether);
returnWei = weiAmount.sub(newWei);
weiAmount = newWei;
tokens = newTokens;
}
tokensSold = tokensSold.add(tokens); // Increment raised amount
remainingTokens = cap.sub(tokensSold);
if(returnWei > 0){
msg.sender.transfer(returnWei);
emit Transfer(address(this), msg.sender, returnWei);
}
balances[msg.sender] = balances[msg.sender].add(tokens);
emit Transfer(address(this), msg.sender, tokens);
totalSupply_ = totalSupply_.add(tokens);
owner.transfer(weiAmount);// Send money to owner
}
/**
* @dev startIco starts the public ICO
**/
function startIco() public onlyOwner {
require(currentStage != Stages.icoEnd);
currentStage = Stages.icoStart;
}
/**
* @dev endIco closes down the ICO 
**/
function endIco() internal {
currentStage = Stages.icoEnd;
// Transfer any remaining tokens
if(remainingTokens > 0)
balances[owner] = balances[owner].add(remainingTokens);
// transfer any remaining ETH balance in the contract to the owner
owner.transfer(address(this).balance); 
}
/**
* @dev finalizeIco closes down the ICO and sets needed varriables
**/
function finalizeIco() public onlyOwner {
require(currentStage != Stages.icoEnd);
endIco();
}
}
/**
* @title LavevelToken 
* @dev Contract to create the Lavevel Token
**/
contract AlexToken is CrowdsaleToken {
string public constant name = "AlexToken";
string public constant symbol = "ALT";
uint32 public constant decimals = 18;
}

ac binarii repraesentatio retiacula videt

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

Plura de contractibus captiosis inveniri possunt in articulo: Quid sapis contractus in Ethereum.

conclusio,

Recensuimus technologias quibus moderni impedimenta construuntur et quomodo inter se coniunguntur. Nunc exponamus quae difficultates utendo clausurae solvi possunt, quaeque solutiones ad melius inefficaces erunt. Usura igitur scandali non est necessaria;

• Transactiones in ambitu creditorum peraguntur;
• Praesentia commissionis internuntiorum vitam participantium non peiorat;
• Participes proprietatem non habent quae tamquam res digitales repraesentari possunt;
• Non est distributio bonorum digitalium, i.e. ad valorem possidetur vel suppletur una tantum particeps.

Quid impedit futurum? Nunc solum possumus vias possibilis speculari ad technologias impedimenti evolutionis:

• Claustrum eadem technologia datorum communium fiet ac, exempli gratia, SQL vel NoSQL ad solvendas suas specificas difficultates solvendas;
• Claustrum protocollum diffusum fiet, sicut HTTP est pro Interreti;
• Claustrum fiet fundamentum novae systematis oeconomici et politici in planeta!

In altera parte videbimus quid nunc sint impedimenta et cur in diversis industriis adhibeantur.

Hoc modo initium est!

Source: www.habr.com