Blocto
Technical Documents
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:
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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