Bitcore provides a very simple API for creating transactions.We expect this API to be accessible for developers without knowing the working internals of bitcoin in deep detail.What follows is a small introduction to transactions with some basic knowledge required to use this API.A Transaction contains a set of inputs and a set of outputs.Each input contains a reference to another transaction's output, and a signature that allows the value referenced in that output to be used in this transaction.Note also that an output can be used only once.That's why there's a concept of "change address" in the bitcoin ecosystem: if an output of 10 BTC is available for me to spend, but I only need to transmit 1 BTC, I'll create a transaction with two outputs, one with 1 BTC that I want to spend, and the other with 9 BTC to a change address, so I can spend this 9 BTC with another private key that I own.So, in order to transmit a valid transaction, you must know what other transactions on the network store outputs that have not been spent and that are available for you to spend (meaning that you have the set of keys that can validate you own those funds).

The unspent outputs are usually referred to as "utxo"s.Let's take a look at some very simple transactions: You can obtain the input and output total amounts of the transaction in satoshis by accessing the fields inputAmount and outputAmount.Now, this could just be serialized to hexadecimal ASCII values (transaction.serialize()) and sent over to the bitcoind reference client.You can also override the fee estimation with another amount, specified in satoshis: To send a transaction to a multisig address, the API is the same as in the above example.To spend outputs that require multiple signatures, the process needs extra information: the public keys of the signers that can unlock that output.This can be serialized and sent to another party, to complete with the needed signatures: Also, you can just send over the signature for your private key: Transfer that over the wire, and on the other side, apply it to a transaction: Transaction inputs are instances of either Input or its subclasses.

Input has some abstract methods, as there is no actual concept of a "signed input" in the bitcoin scripting system (just valid signatures for OP_CHECKSIG and similar opcodes).They are stored in the input property of Transaction instances.Bitcore contains two implementations of Input, one for spending Pay to Public Key Hash outputs (called PublicKeyHashInput) and another to spend Pay to Script Hash outputs for which the redeem script is a Multisig script (called MultisigScriptHashInput).bitcoin rapperAll inputs have the following five properties: Both PublicKeyHashInput and MultisigScriptHashInput cache the information about signatures, even though this information could somehow be encoded in the script.bitcoin playgroundBoth need to have the output property set in order to calculate the sighash so signatures can be created.bitcoin kazanma 2017

Some methods related to adding inputs are: from: A high level interface to add an input from a UTXO.It has a series of variants: from(utxo): add an input from an Unspent Transaction Output.Currently, only P2PKH outputs are supported.from(utxos): same as above, but passing in an array of Unspent Outputs.from(utxo, publicKeys, threshold): add an input that spends a UTXO with a P2SH output for a Multisig script.bitcoin oasisThe publicKeys argument is an array of public keys, and threshold is the number of required signatures in the Multisig script.bitcoin store montrealaddInput: Performs a series of checks on an input and appends it to the end of the input vector and updates the amount of incoming bitcoins of the transaction.bitcoin beats paypaluncheckedAddInput: adds an input to the end of the input vector and updates the inputAmount without performing any checks.litecoin mining video card

This input uses the script property to mark the input as unsigned if the script is empty.This input contains a set of signatures in a signatures property, and each time a signature is added, a potentially partial and/or invalid script is created.The isFullySigned method will only return true if all needed signatures are already added and valid.If addSignature is added after all need signatures are already set, an exception will be thrown.bitcoin add nodesThe following methods are used to manage signatures for a transaction: getSignatures: takes an array of PrivateKey or strings from which a PrivateKey can be instantiated; the transaction to be signed; the kind of signature hash to use.ethereum farmingReturns an array of objects with the following properties: signature: an instance of Signature prevTxId: this input's prevTxId, outputIndex: this input's outputIndex, inputIndex: this input's index in the transaction sigtype: the "sighash", the type of transaction hash used to calculate the signature publicKey: a PublicKey of the PrivateKey used to create the signature addSignature: takes an element outputed by getSignatures and applies the signature to this input (modifies the script to include the new signature).

clearSignatures: removes all signatures for this input isFullySigned: returns true if the input is fully signed Outputs can be added by: To remove all outputs, you can use clearOutputs(), which preserves change output configuration.There are a series of methods used for serialization: When serializing, the bitcore library performs a series of checks.These can be disabled by providing an object to the serialize method with the checks that you'll like to skip.These are the current default values in the bitcore library involved on these checks: When outputs' value don't sum up to the same amount that inputs, the difference in bitcoins goes to the miner of the block that includes this transaction.The concept of a "change address" usually is associated with this: an output with an address that can be spent by the creator of the transaction.For this reason, some methods in the Transaction class are provided: Internally, a _changeIndex property stores the index of the change output (so it can get updated when a new input or output is added).

All bitcoin transactions contain a locktime field.The locktime indicates the earliest time a transaction can be added to the blockchain.Locktime allows signers to create time-locked transactions which will only become valid in the future, giving the signers a chance to change their minds.Locktime can be set in the form of a bitcoin block height (the transaction can only be included in a block with a higher height than specified) or a linux timestamp (transaction can only be confirmed after that time).For more information see bitcoin's development guide section on locktime.In bitcore, you can set a Transaction's locktime by using the methods Transaction#lockUntilDate and Transaction#lockUntilBlockHeight.You can also get a friendly version of the locktime field via Transaction#getLockTime; We're debating an API for Merge Avoidance, CoinJoin, Smart contracts, CoinSwap, and Stealth Addresses.We're expecting to have all of them by some time in 2015.Payment channel creation is available in the bitcore-channel module.