[code=php]
<?php
function foo() {
    $s = hash_hmac('sha256', 'Message', 'secret', true);
    echo base64_encode($s);
}
?>
[/code]

[code=golang]
import (
    b64 "encoding/base64"
    "crypto/hmac"
    "crypto/sha256"
)

//genHMAC256 generates a hash signature of the encrypted text
func genHMAC256(ciphertext, key []byte) []byte {
	mac := hmac.New(sha256.New, key)
	mac.Write([]byte(ciphertext))
	hmac := mac.Sum(nil)
	return hmac
}


...
hmac := genHMAC256([]byte('Message'), []byte('secret'))
stringHmac := b64.StdEncoding.EncodeToString(sha)
...

[/code]