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Sign Message
Sign and verify challenges for off-chain authentication
For dApps relying on signMessage for off-chain authentication, Blocto follows EIP-1654. To verify the signature, you need to call a method on the wallet contract to check if the signature came from a rightful owner of the wallet contract.
Dapper Labs has built the tools to carry out this verification:
​Go implementation​
​JavaScript implementation​
Use it in your dApps:
Go
JavaScript
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package main
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​
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import (
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	"log"
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	"net/http"
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​
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	"github.com/ethereum/go-ethereum/ethclient"
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	"github.com/dapperlabs/dappauth"
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)
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​
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// AuthenticationHandler ..
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type AuthenticationHandler struct {
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	client *ethclient.Client
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}
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​
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// NewAuthenticationHandler ..
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func NewAuthenticationHandler(rawurl string) (*AuthenticationHandler, error) {
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	client, err := ethclient.Dial(rawurl)
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	if err != nil {
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		return nil, err
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	}
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	return &AuthenticationHandler{client: client}, nil
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}
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​
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// ServeHTTP serves just a single route for authentication as an example
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func (a *AuthenticationHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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​
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	challenge := r.PostFormValue("challenge")
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	signature := r.PostFormValue("signature")
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	addrHex := r.PostFormValue("addrHex")
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​
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	authenticator := dappauth.NewAuthenticator(r.Context(), a.client)
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	isAuthorizedSigner, err := authenticator.IsAuthorizedSigner(challenge, signature, addrHex)
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	if err != nil {
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		// return a 5XX status code
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	}
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	if !isAuthorizedSigner{
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		// return a 4XX status code
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	}
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​
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	// create an authenticated session for address
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	// return a 2XX status code
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}
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​
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func main() {
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	handler, err := NewAuthenticationHandler("https://mainnet.infura.io")
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	if err != nil {
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		log.Fatal(err)
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	}
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​
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	log.Fatal(http.ListenAndServe(":8080", handler))
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}
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const Web3 = require('web3');
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const DappAuth = require('@dapperlabs/dappauth');
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​
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const dappAuth = new DappAuth(new Web3.providers.HttpProvider('http://localhost:8545'));
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​
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async function debug() {
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  const challenge = 'foo';
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  const signature =
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    '0x33838c6f4e621982c2009f9b93ecb854a4b122538159623abc87d2e4c5bd6d2e33591f443b419b3bd2790e455ba6d625f2ca14b822c5cef824ef7e9021443bed1c';
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  const address = '0x86aa354fc865925f945b803ceae0b3f9d856b269';
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​
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  try {
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    const isAuthorizedSigner = await dappAuth.isAuthorizedSigner(
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      challenge,
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      signature,
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      address,
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    );
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​
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    console.log(isAuthorizedSigner); // true
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  } catch (e) {
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    console.log(e);
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  }
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}
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Web3.js Integration (Ethereum/BSC/Polygon/Avalanche/Tron)
Batch Transaction
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