Go

Proof Service

You can git clone and run Go open demo for help.

The core example of codes:

cmd/playground.go

package main

import (
    "crypto/ecdsa"
    "fmt"

    "github.com/ethereum/go-ethereum/common/hexutil"
    "github.com/ethereum/go-ethereum/crypto"
)

const (
    // ATTENTION! We intently replaced the last three digit of private key to be xxx.
    // Private key is everything and NEVER expose it to others or publicly
    SECRET_KEY   = "43c25fecc20e6b2a0d86c81a0202d125c0181deb9975d1170d80378c7e05bxxx"
    SIGN_PAYLOAD = "Test123123!"
)

func main() {
    sk, err := crypto.HexToECDSA(SECRET_KEY)
    if err != nil {
        panic(err)
    }

    sign, err := signPersonal([]byte(SIGN_PAYLOAD), sk)
    if err != nil {
        panic(err)
    }

    fmt.Printf("Signature: %s\n", hexutil.Encode(sign))
    // Signature: 0x52f210dadad13c4c8d0656e7380300a367a056631cf26950baa7de4f580187795c76b5fc94de5bd0b8af4d5df432687d900402cba86a12570af56be35ba8d56401
}

// signPersonal signs a payload using given secret key.
func signPersonal(payload []byte, sk *ecdsa.PrivateKey) (signature []byte, err error) {
    digest := signPersonalDigest(payload)
    signature, err = crypto.Sign(digest, sk)
    if err != nil {
        return nil, err
    }

    return signature, nil
}

// signPersonalDigest hashes the given payload with eth.personal.sign struct.
func signPersonalDigest(data []byte) []byte {
    messsage := fmt.Sprintf("\x19Ethereum Signed Message:\n%d%s", len(data), data)
    return crypto.Keccak256([]byte(messsage))
}