Generating a SHA256 HMAC Hash

· 170 words · 1 minute read
#crypto #sha256 #signature #hash #key #secret #hmac

Generating HMACs (Keyed-Hash Message Authentication Code) are often used as a way of proving data integrity and authenticity. They involve three integrals parts, the algorithm (in our case SHA256), the secret and the data. They a used mainly because data can be checked between two parties without the sharing of the secret.

In go, there’s a convenient library to help us out with this called crypto/hmac and we show an example of how to do this below.

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package main

import (
    "crypto/hmac"
    "crypto/sha256"
    "encoding/hex"
    "fmt"
)

func main() {

    secret := "mysecret"
    data := "data"
    fmt.Printf("Secret: %s Data: %s\n", secret, data)

    // Create a new HMAC by defining the hash type and the key (as byte array)
    h := hmac.New(sha256.New, []byte(secret))

    // Write Data to it
    h.Write([]byte(data))

    // Get result and encode as hexadecimal string
    sha := hex.EncodeToString(h.Sum(nil))

    fmt.Println("Result: " + sha)
}

Example:

Generate SHA256 signature

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Author:  Edd Turtle

Edd is the Lead Developer at Hoowla, a prop-tech startup, where he spends much of his time working on production-ready Go and PHP code. He loves coding, but also enjoys cycling and camping in his spare time.

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