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Ethereum Input Data Decoder

Ethereum (column 80)

Ethereum (column 80)

I have an ABI and the input value of the transaction and want toknow what function has been called on a contract and with what arguments (one ormultiple of different types), preferably using geth,JSON-RPC and some pseudo code that I can then translate intoRuby. There are a couple of similar questions on SO but none of them reallyanswered the question in a way that's understandable to someone new toEthereum. contract generated by Truffle. I call the methodgetBalance('0xfd46f749f9d916122fe958d7f8d5ad033b187472') and getthe input0xf8b2cb4f000000000000000000000000fd46f749f9d916122fe958d7f8d5ad033b187472. truffle(development)>web3.eth.getTransaction('0x5d7a91c9f068d723ac52480c0ef61b9bf3f7b52dc726046e0b47f1beaa2f44ff'){ hash: '0x5d7a91c9f068d723ac52480c0ef61b9bf3f7b52dc726046e0b47f1beaa2f44ff', nonce: 5, blockHash:'0xd150b520eb69a621a7218722c0de5b270c9abc499a90a81ca96340e274599c28', blockNumber: 6, transactionIndex: 0, from: '0xfd46f749f9d916122fe958d7f8d5ad033b187472', to: '0x8dec2f9cccbe718c7c51e9154f223eb226bb7942', value: { [String: '0'] s: 1, e: 0, c: [ 0 ] }, gas: 4712388, gasPrice: { [String: '100000000000'] s: 1, e: 11, c: [ 100000000000 ] }, input:'0xf8b2cb4f000000000000000000000000fd46f749f9d916122fe958d7f8d5ad033b187472' } [ { "constant": false, "inputs": [ { "name": "addr", "type": "address" } ], "name": "getBalanceInEth", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "type": "function" }, { "constant": false, "inputs": [ { "name": "receiver", "type": "address" }, { "name": "amount", "type": "uint256" } ], "name": "sendCoin", "outputs": [ { "name": "sufficient", "type": "bool" } ], "payable": false, "type": "function" }, { "constant": false, "inputs": [ { "name": "addr", "type": "address" } ], "name": "getBalance", "outputs": [ { "name": "", Continue reading >>

Rlp - Godoc

Rlp - Godoc

import "github.com/ethereum/go-ethereum/rlp" Package rlp implements the RLP serialization format. The purpose of RLP (Recursive Linear Prefix) is to encode arbitrarilynested arrays of binary data, and RLP is the main encoding method usedto serialize objects in Ethereum. The only purpose of RLP is to encodestructure; encoding specific atomic data types (eg. strings, ints,floats) is left up to higher-order protocols; in Ethereum integersmust be represented in big endian binary form with no leading zeroes(thus making the integer value zero equivalent to the empty bytearray). RLP values are distinguished by a type tag. The type tag precedes thevalue in the input stream and defines the size and kind of the bytesthat follow. var ( // EOL is returned when the end of the current list // has been reached during streaming. EOL = errors . New ("rlp: end of list") // Actual Errors ErrExpectedString = errors . New ("rlp: expected String or Byte") ErrExpectedList = errors . New ("rlp: expected List") ErrCanonInt = errors . New ("rlp: non-canonical integer format") ErrCanonSize = errors . New ("rlp: non-canonical size information") ErrElemTooLarge = errors . New ("rlp: element is larger than containing list") ErrValueTooLarge = errors . New ("rlp: value size exceeds available input length") // This error is reported by DecodeBytes if the slice contains // additional data after the first RLP value. ErrMoreThanOneValue = errors . New ("rlp: input contains more than one value")) func Decode(r io . Reader , val interface{}) error Decode parses RLP-encoded data from r and stores the result in thevalue pointed to by val. Val must be a non-nil pointer. If r doesnot implement ByteReader, Decode will do its own buffering. Decode uses the following type-dependent decoding rules: If the type im Continue reading >>

Keep Your Private Keys Close And Keep Your Smart Contracts Closerintroducing The Smart Contractwatch

Keep Your Private Keys Close And Keep Your Smart Contracts Closerintroducing The Smart Contractwatch

A Software Developer at Neufund, with a Background in Computer Engineering. Keep Your Private Keys Close and Keep Your Smart Contracts Closer Introducing The Smart ContractWatch Monitoring your servers, services or micro-services usually is considered a priority, in order to see if everything is running as it should and additionally receive instant alerts in case of any suspicious or unplanned activity. Usually, when running a regular backend service, the idea of monitoring your servers is straightforward with many options to choose from. In the blockchain (Distributed Ledger), things run a bit differently: the whole blockchain is your backend and there are no dedicated servers you can monitor in order to check your smart contracts activity. The only way to check how your smart contracts are interacting in the blockchain is to scan the blockchain block by block (as they come) for any transactions or events related to your smart contract. Like the role of the lookout in a ship, you must have the right tool that scans for anything fishy coming your way Source:This manual process of block scanning is made easier by blockchain explorers like Etherscan . They explore the whole blockchain and most of the information needed can be found using them as a platform. Blockchain explorers are a good start if you want to do quick infrequent checks but their shortcomings start to show if any serious smart contract monitoring effort is considered, for example: You have no control on what is scanned or what should be scanned, in terms of parameters or activity, as you only assume that these explorers scan and log everything. The explorers are not running locally so you are at risk if they fail, and thus have no control or guarantee that these services will keep running. These explorers Continue reading >>

Help: How To Decode Input Data From Tx? : Ethereum

Help: How To Decode Input Data From Tx? : Ethereum

0xa9059cbb00000000000000000000000067fa2c06c9c6d4332f330e14a66bdf1873ef3d2b0000000000000000000000000000000000000000000000000de0b6b3a7640000 I know that the first 4 bytes represent the function (0xa9059cbb --> transfer) The first parameter is the _to address (0x00000000000000000000000067fa2c06c9c6d4332f330e14a66bdf1873ef3d2b) The second is _value who's type is uint256 (0x0000000000000000000000000000000000000000000000000de0b6b3a7640000). How do I decode _value in python to get the amount of tokens being moved? I understand that for javascript there is abi-decoder which does something similar but I would like to know how to perform this myself in python. I have read that the value is stored as a big endian int but when I try to read it, I do not get the value listed on etherscan for the transaction ( ) The information I have about the parameter coding is from here: Continue reading >>

Blockchain - How To Decode Input Data From A Transaction? - Ethereum Stack Exchange

Blockchain - How To Decode Input Data From A Transaction? - Ethereum Stack Exchange

How to decode input data from a transaction? I'm sending a transaction to an account with some data with the following command: eth.sendTransaction({from:eth.accounts[0],to:eth.accounts[1],value:web3.toWei(1,"ether"),data:web3.toHex("I'm getting this result, by extracting the log of the transaction (running with testRPC): tx hash : 0xf654aee5ed23f9aeebd2d73c69c7b9c21a4862787966d09bcb09ed44efc1f252 nonce : 0 blockHash : 0x6ff8a0e3ac606abd2ede4331b82af52a0daa98448025051fb3b3d50f749aa49f blockNumber : 1 transactionIndex: 0 from : 0xf64918835bc21dff9e8210a807b3964d1be35dd0 to : 0x08f986b7535c2b72687d3cb193135f1c6e27c336 value : 1000000000000000000 time : 1483614904 Thu, 05 Jan 2017 11:15:04 GMT gasPrice : 1 gas : 90000 input : 0x687474703a2f2f6c6f63616c686f73743a38353435 I want to decode the last line "input" and try to get " ".I saw some work similar to my question here and here , but this is not working in my case. Moreover, i tried .toString('hex')) but it remains as hex. Continue reading >>

How To Find $10m Just By Reading The Blockchain

How To Find $10m Just By Reading The Blockchain

How to Find $10M Just by Reading the Blockchain Two weeks ago, one Golem enthusiast and GNT holder reported a strange GNT transfer transaction bug. After investigating the data attached to the transaction, I discovered that there had to be a problem in the way the exchange was preparing data for the transaction. Oh no, I thought, this bug could be used to empty the whole GNT account on the exchange! And quite a large number of tokens were stored there! The bug was indeed the exchanges fault, but it was also related to the way Ethereum contracts see the transaction input data and Solidity ABI (e.g. the way the methods of Solidity contracts encode and decode arguments). So of course it was not specific to GNT, but indeed to all ERC20 tokens, as well as other contracts which have transfer-like methods. Yes you read it right: this could potentially work for any Ethereum-based token listed on said exchange, if only withdrawals were managed in the same way as GNT. We do not know this to be the case, but assume it was very likely. Raw Ethereum contracts have neither methods nor functions. Methods are features of high level languages like Solidity, and they use the Ethereum Contract ABI to specify how a contracts bytecode is divided into methods, as well as how different types of arguments are encoded in transaction input data. (See for a reference.) To invoke the transfer(address a, uint v) method of the GNT contract to transfer 1 GNT to address 0xabcabcabcabcabcabcabcabcabcabcabcabcabca one needs to include 3 pieces of data: 32 bytes, with the destination address (20 bytes) filled with leading zeros: 000000000000000000000000abcabcabcabcabcabcabcabcabcabcabcabcabca 32 bytes, being the value to transfer, 1 * 10 GNT: 0000000000000000000000000000000000000000000000000de0b6b3a7640 Continue reading >>

Ethereum Accounts, Address And Contracts

Ethereum Accounts, Address And Contracts

/// auth.sol -- widely-used access control pattern for Ethereum// Copyright (C) 2015, 2016, 2017 DappHub, LLC// Licensed under the Apache License, Version 2.0 (the "License").// You may not use this file except in compliance with the License.// Unless required by applicable law or agreed to in writing, software// distributed under the License is distributed on an "AS IS" BASIS,// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND (express or implied).pragma solidity ^0.4.13;contract Authority { function canCall(address src, address dst, bytes4 sig) constant returns (bool);}contract AuthEvents { event LogSetAuthority (address indexed authority); event LogSetOwner (address indexed owner); event UnauthorizedAccess (address caller, bytes4 sig);}contract Auth is AuthEvents { Authority public authority; address public owner; function Auth() { owner = msg.sender; LogSetOwner(msg.sender); } function setOwner(address owner_) auth { owner = owner_; LogSetOwner(owner); } function setAuthority(Authority authority_) auth { authority = authority_; LogSetAuthority(authority); } modifier auth { require(isAuthorized(msg.sender, msg.sig)); _; } function isAuthorized(address src, bytes4 sig) internal returns (bool) { if (src == address(this)) { return true; } else if (src == owner && authority == Authority(0)) { /*the owner has privileges only as long as no Authority has been defined*/ return true; } else if (authority == Authority(0)) { UnauthorizedAccess(src, sig); return false; } else { return authority.canCall(src, this, sig); } }}/* Copyright 2017 DappHub, LLC Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at Unless required by applicable law or agreed to in writing, soft Continue reading >>

Help: How To Decode Input Data From Tx? Reddit.com

Help: How To Decode Input Data From Tx? Reddit.com

I am trying to decode input data from token sale transactions. This is one of the transactions I am trying to parse. 0xf7b7196ca9eab6e4fb6e7bce81aeb25a4edf04330e57b3c15bece9d260577e2b. Which has the following input data:. 0xa9059cbb00000000000000000000000067fa2c06c9c6d4332f330e14a66bdf1873ef3d2b0000000000000000000000000000000000000000000000000de0b6b3a7640000. I know that the first 4 bytes represent the function (0xa9059cbb --> transfer). The first parameter is the _to address (0x00000000000000000000000067fa2c06c9c6d4332f330e14a66bdf1873ef3d2b). The second is _value who's type is uint256 (0x0000000000000000000000000000000000000000000000000de0b6b3a7640000).. How do I decode _value in python to get the amount of tokens being moved? I understand that for javascript there is abi-decoder which does something similar but I would like to know how to perform this myself in python.. I have read that the value is stored as a big endian int but when I try to read it, I do not get the value listed on etherscan for the transaction (The information I have about the parameter coding is from here: Coin spectator is an automated news aggregation service. All copyrights belong to their respective owners. Images and text owned by copyright holders are used in reference to and promotion of those respective parties. Continue reading >>

Deep Dive Into Ethereumlogs

Deep Dive Into Ethereumlogs

Hey kids, today we are going low level trying to understand how Ethereum events and logs work. Put web3 away for a while as it abstracts things and wed like to get as bare as it gets. Smart contracts generate logs by firing events. Heres a transaction receipt that contains one log entry. The log entry consists of one topic and a data field. The first topic refers to the specific event, but we dont know which one yet. To decode the data we need to obtain ABI of the contract found in the address field. We are interested in items with the type event. Heres a sample event. > indexed_types = [i['type'] for i in e['inputs'] if i['indexed']] > indexed_names = [i['name'] for i in e['inputs'] if i['indexed']] > indexed_values = [eth_abi.decode_single(t, v) for t, v in zip(indexed_types, log['topics'][1:])] ['0x00b46c2526e227482e2ebb8f4c69e4674d262e75', > {name: value for name, value in chain(zip(names, values), zip(indexed_names, indexed_values))} {'from': '0x00b46c2526e227482e2ebb8f4c69e4674d262e75', 'to': '0x54a2d42a40f51259dedd1978f6c118a0f0eff078', Note that Ethereum always uses integers to represent numeric values, so we got the value in the minimal denomination. Move the decimal point left by decimals found in the contract, 3 in this case. The message reads: Transfer from 0x00b4 to 0x54a2 of 5,000,000 tokens. Now you are ready to do some search. You can query the blockchain using json-rpc api which is provided by full nodes like geth or Parity or a service like Infura. Bloom filters allow you to scan the entire blockchain in seconds and find logs matching the specific topic. You can also specify search range with fromBlock and toBlock, limit the search to specific contract address and omit some of the topics with null which works like a wildcard. The full specification ca Continue reading >>

Data Structure In Ethereum. Episode 1: Recursive Length Prefix (rlp) Encoding/decoding.

Data Structure In Ethereum. Episode 1: Recursive Length Prefix (rlp) Encoding/decoding.

Data structure in Ethereum. Episode 1: Recursive Length Prefix (RLP) Encoding/Decoding. There are literally a lot of papers, blogs which explain how Ethereum organizes its data, but they all seem to be so disconnected and really hard to get an overall picture. In order to help you and confirm my understanding by the way, this series will explain one by one problem of data structure in Ethereum. I will break out this subject into 5 main episodes and 1 extra espisode (I will call it the 1+ espisode): Recursive Length Prefix (RLP) Encoding/Decoding. And 1+ for Hex Prefix Encoding. First of all, we are going to make sense about RLP, so what is the purpose of RLP in Ethereum? In computer science, data serialization is necessary for many complex data forms to be stored or transmitted in only one formal format. Because of that, RLP is an encoding/decoding algorithm that helps Ethereum to serialize data and possible to reconstruct them quickly. As Ethereum mentioned, the RLP encoding function takes in an item. An item is defined as follows A string (will be converted to byte array) is an item For example, all of objects below are items: If input is a single byte in the [0x00, 0x7f] range, so itself is RLP encoding. If input is non-value (uint(0), []byte{}, string(), empty pointer), RLP encoding is 0x80. Notice that0x00 value byte is not non-value. If input is a string with 255 bytes long, RLP encoding consists of a single byte with value 0x80 plus the length of the string in bytes and then array of hex value of string. Its easy to see that the first byte is in [0x81, 0xb7] range. For example: hello world = [0x8b, 0x68, 0x65, 0x6c, 0x6c, 0x6f, 0x20, 0x77, 0x6f, 0x72, 0x6c, 0x64], because hello world has 11 bytes in dec or 0x0b in hex, so the first byte of RLP encoding is 0x80 + Continue reading >>

Github - Miguelmota/ethereum-input-data-decoder: Ethereum Smart Contract Transaction Input Data Decoder

Github - Miguelmota/ethereum-input-data-decoder: Ethereum Smart Contract Transaction Input Data Decoder

Ethereum smart contract transaction input data decoder Pass ABI file path to decoder constructor: const InputDataDecoder = require('ethereum-input-data-decoder');const decoder = new InputDataDecoder(`${__dirname}/abi.json`); Alternatively, you can pass ABI array object to constructor; const abi = [{ ... }]const decoder = new InputDataDecoder(abi); const data = `0x67043cae0000000000000000000000005a9dac9315fdd1c3d13ef8af7fdfeb522db08f020000000000000000000000000000000000000000000000000000000058a20230000000000000000000000000000000000000000000000000000000000040293400000000000000000000000000000000000000000000000000000000000000a0f3df64775a2dfb6bc9e09dced96d0816ff5055bf95da13ce5b6c3f53b97071c800000000000000000000000000000000000000000000000000000000000000034254430000000000000000000000000000000000000000000000000000000000`;const result = decoder.decodeData(data);console.log(result); { "method": "registerOffChainDonation", "types": [ "address", "uint256", "uint256", "string", "bytes32" ], "inputs": [ , , , "BTC", ], "names": [ "addr", "timestamp", "chfCents", "currency", "memo" ]} Example using input response from web3.getTransaction : web3.eth.getTransaction(txHash, (error, txResult) => { const result = decoder.decodeData(txResult.input); console.log(result);}); All numbers are returned in big number format to preserve precision. Here's an example of how to convert the big number to a human readable format. console.log(result.inputs[0].toString(10)) // "5"console.log(result.inputs[0].toNumber()) // 55 Please keep in mind that JavaScript only supports numbers up to 64 bits. Solidity numbers can be up to 256 bits, so you run the risk of truncation when casting or having the big number library error out when trying to parse a large number to a JavaScript Number type. const n = new B Continue reading >>

Blockchain - How To Decode Input Data From A Transaction? - Ethereum Stack Exchange

Blockchain - How To Decode Input Data From A Transaction? - Ethereum Stack Exchange

How to decode input data from a transaction? I'm sending a transaction to an account with some data with the following command: eth.sendTransaction({from:eth.accounts[0],to:eth.accounts[1],value:web3.toWei(1,"ether"),data:web3.toHex("I'm getting this result, by extracting the log of the transaction (running with testRPC): tx hash : 0xf654aee5ed23f9aeebd2d73c69c7b9c21a4862787966d09bcb09ed44efc1f252 nonce : 0 blockHash : 0x6ff8a0e3ac606abd2ede4331b82af52a0daa98448025051fb3b3d50f749aa49f blockNumber : 1 transactionIndex: 0 from : 0xf64918835bc21dff9e8210a807b3964d1be35dd0 to : 0x08f986b7535c2b72687d3cb193135f1c6e27c336 value : 1000000000000000000 time : 1483614904 Thu, 05 Jan 2017 11:15:04 GMT gasPrice : 1 gas : 90000 input : 0x687474703a2f2f6c6f63616c686f73743a38353435 I want to decode the last line "input" and try to get " ".I saw some work similar to my question here and here , but this is not working in my case. Moreover, i tried .toString('hex')) but it remains as hex. Continue reading >>

Keyword - Decoder

Keyword - Decoder

abi-decoder Nodejs and Javascript library for decoding data params and events from ethereum transactions" abi-decoder-with-mocha-update A fork of abi-decoder with an updated version of mocha" aco-decoder Decodes Adobe Color Files (.aco) to color formats addon-jwt-decoder Congratulations! You've successfully created an Atlassian Connect Add-on using the Express web application framework. ais-decoder GEOGATE-geojson handles AIS/NMEA encoding/decoding for GEOgate GPS/AIS/GTS framework aisdecoder Decode AIS messages to Javascript objects array_decoder Like string_decoder but for arrays audio-buffer-range-decoder Decode specified ranges of PCM Wave and Opus webm files on disk to AudioBuffers. Probably only works with electron. autodetect-decoder-stream An iconv-lite stream that autodetects the encoding and fallbacks to a specified fallback encoding. aztec-decoder Biblioteka programistyczna pozwalajca na dekodowanie danych z dowodw rejestracyjnych pojazdw samochodowych zapisanych w formie kodu AZTEC 2D. base64-encoder-decoder Base64 encoder and decoder bitcoin-txdecoder transaction decode hex string cborjs-typedarray-decoder Decodes typed arrays from CBOR cgjs-string_decoder string_decoder core module for cgjs cisco-password-decoder CLI Decoder for password encoding of Cisco VPN client cordova-plugin-cortex-decoder Cortex Barcode Decoder core-string-decoder The 'string_decoder' module from Node core decoder-ring Decode binary buffers using a JSON specification decoder.flow Library for turning arbitrary input into a typed data. decoders Elm-like decoders for when working with Flow types in JS edfdecoder Decode EDF (European Data Format) files in pure Javascript for Node and browser ee-mime-decoder streaming mime message decoder, supports streaming of attachments & file upload Continue reading >>

Ethereum.transactions.transaction Python Example

Ethereum.transactions.transaction Python Example

Project: PyWalletAuthor: AndreMirasFile: pywalib.py View Source Project def transact(self, to, value=0, data='', sender=None, startgas=25000, gasprice=60 * denoms.shannon): """ Inspired from pyethapp/console_service.py except that we use Etherscan for retrieving the nonce as we as for broadcasting the transaction. Arg value is in Wei. """ # account.unlock(password) sender = normalize_address(sender or self.get_main_account().address) to = normalize_address(to, allow_blank=True) nonce = PyWalib.get_nonce(sender) # creates the transaction tx = Transaction(nonce, gasprice, startgas, to, value, data) # then signs it self.app.services.accounts.sign_tx(sender, tx) assert tx.sender == sender PyWalib.add_transaction(tx) return tx Project: eth-testerAuthor: ethereumFile: main.py View Source Project def _get_transaction_by_hash(evm, transaction_hash): for index, candidate in enumerate(evm.block.transactions): if transaction_hash == candidate.hash: return ( evm.block, candidate, index, True, ) for block_number in range(evm.chain.head.number, -1, -1): block = _get_block_by_number(evm, block_number) for index, transaction in enumerate(block.transactions): if transaction.hash == transaction_hash: return block, transaction, index, False else: raise TransactionNotFound( "Transaction with hash {0} not found".format( transaction_hash, ) ) Project: pyethereumAuthor: ethereumprojectFile: tester.py View Source Project def mkspv(self, sender, to, value, data=None, funid=None, abi=None): # pylint: disable=too-many-arguments # TODO: rewrite the method without using encode_abi/encode_datalist # since both function were removed. raise NotImplementedError() # if not HAS_SERPENT: # raise RuntimeError('ethereum-serpent package not installed') # data = data or list() # sendnonce = self.block.get_no Continue reading >>

Web3.eth.abi Web3.js 1.0.0 Documentation

Web3.eth.abi Web3.js 1.0.0 Documentation

String - The ABI signature of the function. // From a JSON interface objectweb3.eth.abi.encodeFunctionSignature({ name: 'myMethod', type: 'function', inputs: [{ type: 'uint256', name: 'myNumber' },{ type: 'string', name: 'myString' }]})> 0x24ee0097// Or stringweb3.eth.abi.encodeFunctionSignature('myMethod(uint256,string)')> '0x24ee0097' web3.eth.abi.encodeEventSignature(eventName); Encodes the event name to its ABI signature, which are the sha3 hash of the event name including input types. 1. eventName - String|Object: The event name to encode.or the JSON interface object of the event. If string it has to be in the form event(type,type,...), e.g: myEvent(uint256,uint32[],bytes10,bytes) web3.eth.abi.encodeEventSignature('myEvent(uint256,bytes32)')> 0xf2eeb729e636a8cb783be044acf6b7b1e2c5863735b60d6daae84c366ee87d97// or from a json interface objectweb3.eth.abi.encodeEventSignature({ name: 'myEvent', type: 'event', inputs: [{ type: 'uint256', name: 'myNumber' },{ type: 'bytes32', name: 'myBytes' }]})> 0xf2eeb729e636a8cb783be044acf6b7b1e2c5863735b60d6daae84c366ee87d97 Encodes a parameter based on its type to its ABI representation. Continue reading >>

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