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 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:

Use it in your dApps:

Go
JavaScript
Go
package main
import (
"log"
"net/http"
"github.com/ethereum/go-ethereum/ethclient"
"github.com/dapperlabs/dappauth"
)
// AuthenticationHandler ..
type AuthenticationHandler struct {
client *ethclient.Client
}
// NewAuthenticationHandler ..
func NewAuthenticationHandler(rawurl string) (*AuthenticationHandler, error) {
client, err := ethclient.Dial(rawurl)
if err != nil {
return nil, err
}
return &AuthenticationHandler{client: client}, nil
}
// ServeHTTP serves just a single route for authentication as an example
func (a *AuthenticationHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
challenge := r.PostFormValue("challenge")
signature := r.PostFormValue("signature")
addrHex := r.PostFormValue("addrHex")
authenticator := dappauth.NewAuthenticator(r.Context(), a.client)
isAuthorizedSigner, err := authenticator.IsAuthorizedSigner(challenge, signature, addrHex)
if err != nil {
// return a 5XX status code
}
if !isAuthorizedSigner{
// return a 4XX status code
}
// create an authenticated session for address
// return a 2XX status code
}
func main() {
handler, err := NewAuthenticationHandler("https://mainnet.infura.io")
if err != nil {
log.Fatal(err)
}
log.Fatal(http.ListenAndServe(":8080", handler))
}
JavaScript
const Web3 = require('web3');
const DappAuth = require('@dapperlabs/dappauth');
const dappAuth = new DappAuth(new Web3.providers.HttpProvider('http://localhost:8545'));
async function debug() {
const challenge = 'foo';
const signature =
'0x33838c6f4e621982c2009f9b93ecb854a4b122538159623abc87d2e4c5bd6d2e33591f443b419b3bd2790e455ba6d625f2ca14b822c5cef824ef7e9021443bed1c';
const address = '0x86aa354fc865925f945b803ceae0b3f9d856b269';
try {
const isAuthorizedSigner = await dappAuth.isAuthorizedSigner(
challenge,
signature,
address,
);
console.log(isAuthorizedSigner); // true
} catch (e) {
console.log(e);
}
}