Golang – How to Sign Pieces of Data with Go-Ethereum

go-ethereumgolangsignature

I'm trying to figure out how to sign a piece of data (in this case a string) using golang. So far everything I can find is about signing transactions which wont work for signing pieces of data that is not of a type transaction.

Best Answer

Figured it out:

// convert string key to byte array
byteKey := []byte(`{....}`)

privKey, err := keystore.DecryptKey(byteKey, string(pass))
if err != nil {
    log.Fatal("error decrypting key")
} else {
    fmt.Printf("key successfully decrypted %v\n", privKey)
}

hash := crypto.Keccak256([]byte("hello"))

sig, err := crypto.Sign(hash, privKey.PrivateKey)
if err != nil {
    log.Fatal("error signing data")
} else {
    fmt.Println("signature successful ", sig)
}

Related Solutions

Web3js – How to Sign a Send Method in Web3 1.0

First, you need to generate your transaction, here is an example:

   let tx_builder = contractInstance.methods.myMethod(arg1, arg2, ...);
let encoded_tx = tx_builder.encodeABI();
let transactionObject = {
    gas: amountOfGas,
    data: encoded_tx,
    from: from_address,
    to: contract_address
};

Then you can sign the transaction, using the address and the private key of this specific address. When it is signed, you can send it to the node:

        web3g.eth.accounts.signTransaction(transactionObject, private_key, function (error, signedTx) {
        if (error) {
        console.log(error);
        // handle error
    } else {
web3g.eth.sendSignedTransaction(signedTx.rawTransaction)
        .on('receipt', function (receipt) {
            //do something
     });
    }

Edit: After signing it, you don't have to send it. You can add it to the batch request.

[Ethereum] How to simply sign an Ethereum transaction

Version 4.x of web3.py requires all addresses use a proper EIP 55 checksum. In my testing, I receive the same error as you until I convert the address to the correct checksummed form (note the capitalization):

0xe980E77404ae62aB0F2d6b8510BD951e25185414

(Note that you also have an extra comma that makes your code syntactically invalid, but I assume that's just a copy/paste error.)

Best Answer

Related Solutions

Web3js – How to Sign a Send Method in Web3 1.0

[Ethereum] How to simply sign an Ethereum transaction

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