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Creating Signatures
Signature
A signature helps us to verify that a piece of data was signed by a specific wallet account. There are two types of signatures used in Gluwa API:
- 1.Address Signature
- 2.Transaction Signature
Address Signature
Address signature is used to verify the ownership of a cryptocurrency (e.g., Bitcoin or Ethereum) wallet. A cryptocurrency wallet is a set of a private key and a public key. To generate a signature, you sign a message (or a piece of data) with your private key, and then anyone with your public key can verify the integrity of your signature. To prevent the same signature used over and over again, our APIs mandates the users to use Unix timestamp as the message. The server will check if the timestamp was created no more than 10 minutes ago, and if it has been over 10 minutes, it will deny the request.
Generating Address Signature for Gluwacoins (USD-G, KRW-G, NGN-G)
Since Gluwacoins, such as USD-G, KRW-G and NGN-G, are ERC20 tokens, you can sign a message just like you would on any Ethereum based address. There are libraries out there that can help you create signatures. Some examples include:
JavaScript (web.js)
C# (Nethereum)
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var Web3 = require('web3');
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...
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// replace with your own message and privakey
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var message = "1587674497";
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var privateKey = "0x18cffe0cd4eb63809d0e55ed8dd1aa29e3ac660088e82f7a82977c458f334d8b";
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var web3 = new Web3(Web3.givenProvider);
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var obj = web3.eth.accounts.sign(message , privateKey);
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// signature: 0x96322ca1b963c98e33fe1296b504d3c7adfcfd4e8473bf92f6ee24b560497d16390404a4f9f241d9efdd02cf1fea79d0ebf45d4aa2ef47a4c97fa06750e242301c
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var signature = obj.signature;
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using Nethereum.Signer;
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...
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// replace with your own message and privakey
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string message = "1587674497";
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string privateKey = "0x18cffe0cd4eb63809d0e55ed8dd1aa29e3ac660088e82f7a82977c458f334d8b";
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EthereumMessageSigner signer = new EthereumMessageSigner();
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// signature: 0x96322ca1b963c98e33fe1296b504d3c7adfcfd4e8473bf92f6ee24b560497d16390404a4f9f241d9efdd02cf1fea79d0ebf45d4aa2ef47a4c97fa06750e242301c
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string signature = signer.EncodeUTF8AndSign(message, new EthECKey(privateKey));
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In production environment, your private key should never be hard coded like above. Private keys must be kept secret and be handled with utmost care.
Generating Address Signature for Bitcoin
There are unofficial Bitcoin libraries you can use to create the signature. Some examples include:
BitcoinJS (JavaScript)
NBitcoin (C#)
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var bitcoin = require('bitcoinjs-lib');
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var bitcoinMessage = require('bitcoinjs-message');
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...
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// replace with your own message and privakey
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var network = bitcoin.networks.bitcoin;
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var message = "1587674497";
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var privateKeyString = "KwJfd6xHiqtEFBawy8tKPyJ9TFKQCqHpMr8DQVJ9LbUBj21jqFjE";
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var keyPair = bitcoin.ECPair.fromWIF(privateKeyString, network);
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var privateKey = keyPair.privateKey;
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// signature: H8Gc4g7/X+JsHZyV/qjQSMg9ivoopMztzx9efeV+a+eAJ7Y45OnEi3qmhVWaL743jofge4gQVapzAVsHFSSpBSk=
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var signature = bitcoinMessage
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.sign(message, privateKey, keyPair.compressed)
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.toString('base64');
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using NBitcoin;
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...
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// replace with your own message and privakey
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string message = "1587674497";
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string privateKey = "KwJfd6xHiqtEFBawy8tKPyJ9TFKQCqHpMr8DQVJ9LbUBj21jqFjE";
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BitcoinSecret secret = Network.Main.CreateBitcoinSecret(privateKey);
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// signature: H1iG0zN+TmigcsHDUw2XQo0Wd0LKXbDVG8yr104I0g64cB1kq6WUPKUiI1oNc9Uo9hCRFlfZ3UcALJZNCSy1ZjY=
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string signature = secret.PrivateKey.SignMessage(message);
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// OR you don't have to force low R. Both format is accepted
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// signature: H8Gc4g7/X+JsHZyV/qjQSMg9ivoopMztzx9efeV+a+eAJ7Y45OnEi3qmhVWaL743jofge4gQVapzAVsHFSSpBSk=
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signature = secret.PrivateKey.SignMessage(Encoding.UTF8.GetBytes(message), false);
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Transaction Signature
To create a transaction, you must create a signature of the transfer information so that Gluwa can submit it to the blockchain as a proof-of-intention. Think of signature as a signed contract. You send the contract to Gluwa to submit it to the blockchain for you. The authority (Gluwacoin smart contract or Bitcoin blockchain in this case) can verify that the information in the contract is genuine with your signature.
Generating Transaction Signature for Gluwacoins (USD-G, KRW-G, NGN-G)
Gluwacoin is an ERC-20 token. Users can transfer Gluwacoin as they would transfer any other ERC-20 token. To move tokens on the blockchain, you would normally have to spend Ether to cover the gas for the transaction. However, Gluwacoin allows you to move the coins by paying gas in Gluwacoin instead of Ether. We call this ETHless transfer.
You are going to need the contract addresses to make a transaction signature. Use the following addresses.
Production
Sandbox
ERC20 Contract Addresses
ERC20 Contract Addresses
web3.js (JavaScript)
Nethereum (C#)
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var Web3 = require('web3');
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...
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// replace the values below with your own values
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var contractAddress = "0xfb0aaa0432112779d9ac483d9d5e3961ece18eec"; // USD-G contract
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var sourceAddress = "0x3E6d16c11497aD1A2F47a6594d995f1FaaE727d9";
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var sourcePrivateKey = "0x18cffe0cd4eb63809d0e55ed8dd1aa29e3ac660088e82f7a82977c458f334d8b";
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var targetAddress = "0xc4f7fDf5EB4a1204dCa3BeC609f9E457C4fF9844";
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var amount = 100; // sending 100 USD-G
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var fee = 0.5; // fee is 0.5 USD-G
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var nonce = 1;
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var web3 = new Web3(Web3.givenProvider);
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var hash = web3.utils.soliditySha3({ t: 'address', v: contractAddress },
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{ t: 'address', v: sourceAddress },
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{ t: 'address', v: targetAddress },
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{ t: 'uint256', v: web3.utils.toWei(amount.toString(), 'ether') },
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{ t: 'uint256', v: web3.utils.toWei(fee.toString(), 'ether') },
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{ t: 'uint256', v: nonce });
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var obj = web3.eth.accounts.sign(hash , sourcePrivateKey);
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// signature: 0x8fa899ec93a3f20b5294bed40ab33bac0913b0c9670a48795b99ff8f994526b95e6ff5d7e8ef2ab99c4b1edaf70569b549ba3747e7b4e43ade28405035777bfb1b
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var signature = obj.signature;
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using Nethereum.ABI;
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using Nethereum.Signer;
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using Nethereum.Util;
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using Nethereum.Web3;
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using System.Numerics;
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...
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// replace the values below with your own values
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string contractAddress = "0xfb0aaa0432112779d9ac483d9d5e3961ece18eec"; // USD-G contract
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string sourceAddress = "0x3E6d16c11497aD1A2F47a6594d995f1FaaE727d9";
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string sourcePrivateKey = "0x18cffe0cd4eb63809d0e55ed8dd1aa29e3ac660088e82f7a82977c458f334d8b";
string targetAddress = "0xc4f7fDf5EB4a1204dCa3BeC609f9E457C4fF9844";
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decimal amount = 100m; // sending 100 USD-G
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decimal fee = 0.5m; // fee is 0.5 USD-G
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BigInteger nonce = new BigInteger(1);
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ABIEncode abiEncode = new ABIEncode();
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byte[] hash = abiEncode.GetSha3ABIEncodedPacked(
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new ABIValue("address", contractAddress),
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new ABIValue("address", sourceAddress),
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new ABIValue("address", targetAddress),
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new ABIValue("uint256", Web3.Convert.ToWei(amount, UnitConversion.EthUnit.Ether)),
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new ABIValue("uint256", Web3.Convert.ToWei(fee, UnitConversion.EthUnit.Ether)),
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new ABIValue("uint256", nonce)
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);
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EthereumMessageSigner messageSigner = new EthereumMessageSigner();
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// signature: 0x8fa899ec93a3f20b5294bed40ab33bac0913b0c9670a48795b99ff8f994526b95e6ff5d7e8ef2ab99c4b1edaf70569b549ba3747e7b4e43ade28405035777bfb1b
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string signature = messageSigner.Sign(hash, sourcePrivateKey );
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Note that when you generate the transaction signature, you must multiply the amount and the fee by 10^18 (1,000,000,000,000,000,000). For example, if you want to transfer 10 USD-G, the value for the amount when you create transaction signature must be 10,000,000,000,000,000,000. However, the amount in the transaction request body must be 10.
Generating Transaction Signature for Bitcoin
BitcoinJS (JavaScript)
NBitcoin (C#)
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var bitcoin = require('bitcoinjs-lib');
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var bitcoinMessage = require('bitcoinjs-message');
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...
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var btcToSatoshi = 100000000;
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// replace the values below with your own values
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var network = bitcoin.networks.bitcoin;
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var sourceAddressString = "12koEsMzrdxuZ71ATU1a5jgZyUYtf3debA";
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var sourceAddressPrivateKey = "KwJfd6xHiqtEFBawy8tKPyJ9TFKQCqHpMr8DQVJ9LbUBj21jqFjE";
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var targetAddressString = "14NYL22gWLrVPEdjM6W5oJXcWyu496kZCQ";
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var amountToSend = 0.001;
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var fee = 0.00006;
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var previousTxnHash = "e52fd66f35c48e690d8caada1a881ebb11912c479783f51f839a8827a9afcad4";
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var unspentOutputAmount = 0.03800757;
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var unspentOutputIndex = 1;
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var keyPair = bitcoin.ECPair.fromWIF(sourceAddressPrivateKey, network);
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var txnBuilder = new bitcoin.TransactionBuilder(network);
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txnBuilder.addInput(previousTxnHash, unspentOutputIndex);
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txnBuilder.addOutput(sourceAddressString, (unspentOutputAmount - amountToSend - fee) * btcToSatoshi);
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txnBuilder.addOutput(targetAddressString, amountToSend * btcToSatoshi);
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txnBuilder.sign(0, keyPair);
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var txn = txnBuilder.build();
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// signature: 0200000001d4caafa927889a831ff58397472c9111bb1e881adaaa8c0d698ec4356fd62fe5010000006b483045022100f5e8970b5cb154e96d5696f8fa2c36fabb3e86caf2cd681490448b38403ee92b0220797a0f61f869173d4dbf65894b772cb953349defe2b6275872f0a0b3bc01b86a0121034274d104b6d68ebf109ae3cd35cd53e8b8cd359bedf5598a92033292ae7f76a4ffffffff02a5603800000000001976a91413409c509b056480b21e54d0c5d2b87965eff65188aca0860100000000001976a91424fb438587b31ffd7612f4fbf6d67e21f4bb3ec788ac00000000
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var signature = txn.toHex();
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using NBitcoin;
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...
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// replace the values below with your own values
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Network network = Network.Main;
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string sourceAddressString = "12koEsMzrdxuZ71ATU1a5jgZyUYtf3debA";
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string sourceAddressPrivateKey = "KwJfd6xHiqtEFBawy8tKPyJ9TFKQCqHpMr8DQVJ9LbUBj21jqFjE";
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string targetAddressString = "14NYL22gWLrVPEdjM6W5oJXcWyu496kZCQ";
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decimal amountToSend = 0.001m;
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decimal fee = 0.00006m;
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string previousTxnHash = "e52fd66f35c48e690d8caada1a881ebb11912c479783f51f839a8827a9afcad4";
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string previousTxnScriptPubKey = "76a914b797bc584c969a2b6b5e613c5ab86b5de57c07ec88ac";
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Money unspentOutputAmount = Money.Parse("0.03800757");
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uint unspentOutputIndex = 1;
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BitcoinAddress sourceAddress = BitcoinAddress.Create(sourceAddressString, network);
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BitcoinAddress targetAddress = BitcoinAddress.Create(targetAddressString, network);
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BitcoinSecret secret = new BitcoinSecret(sourceAddressPrivateKey, network);
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TransactionBuilder builder = network.CreateTransactionBuilder();
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Transaction txn = builder
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.AddKeys(secret)
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.AddCoins(
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new Coin(
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fromTxHash: new uint256(previousTxnHash),
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fromOutputIndex: unspentOutputIndex,
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amount: unspentOutputAmount,
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scriptPubKey: Script.FromHex(previousTxnScriptPubKey)
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)
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)
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.Send(targetAddress, amountToSend.ToString())
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.SetChange(sourceAddress)
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.SendFees(fee.ToString())
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.BuildTransaction(true);
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// signature: 0100000001d4caafa927889a831ff58397472c9111bb1e881adaaa8c0d698ec4356fd62fe50100000000ffffffff02a0860100000000001976a91424fb438587b31ffd7612f4fbf6d67e21f4bb3ec788aca5603800000000001976a91413409c509b056480b21e54d0c5d2b87965eff65188ac00000000
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string signature = txn.ToHex();
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Note that the above is just an example. The number of inputs and outputs may differ for each transaction so you may have to rearrange inputs and outputs accordingly.
Reserve Signature
When a market consumer and a market provider agree to exchange currencies, they need to lock the amount that they promised to send to each other so that those funds are available when the exchange actually happens. This process is called “Reserving.”
Since we don’t save the private keys of any user in our system, the user has to give us the txn signature for the reserving funds. There are two types of reservation:
Gluwacoin reservation
Bitcoin reservation
Execute Signature
Reclaim Signature
Last modified 1yr ago
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Contents
Signature
Address Signature
Generating Address Signature for Gluwacoins (USD-G, KRW-G, NGN-G)
Generating Address Signature for Bitcoin
Transaction Signature
Generating Transaction Signature for Gluwacoins (USD-G, KRW-G, NGN-G)
Generating Transaction Signature for Bitcoin
Reserve Signature
Execute Signature
Reclaim Signature