How to generate a SHA256 HMAC in Go // Blog Notes

Here is how to do it in Go:

func main() {
    // create a random 64 bytes (512 bits) secret
    secret := make([]byte, 64)
    _, err := rand.Read(secret)
    if err != nil {
        fmt.Println("error generating a random secret:", err)
        return
    }

    data := []byte("Hello World")

    hmac := hmacSha256(data, secret)

    hmacHex := hex.EncodeToString(hmac)
    hmacBase64 := base64.StdEncoding.EncodeToString(hmac)

    fmt.Println("HMAC-SHA256 Hex:", hmacHex)
    fmt.Println("HMAC-SHA256 Base64:", hmacBase64)
}

func hmacSha256(data, secret []byte) []byte {
    h := hmac.New(sha256.New, secret)
    h.Write(data)
    return h.Sum(nil)
}