OAuthSignatureMethod_HMAC_SHA256.php

<?php
 
namespace ceLTIc\LTI\OAuth;
 
class OAuthSignatureMethod_HMAC_SHA256 extends OAuthSignatureMethod
{
 
    function get_name()
    {
        return "HMAC-SHA256";
    }
 
    public function build_signature($request, $consumer, $token)
    {
        $base_string = $request->get_signature_base_string();
        $request->base_string = $base_string;
 
        $key_parts = array(
            $consumer->secret,
            ($token) ? $token->secret : ""
        );
 
        $key_parts = OAuthUtil::urlencode_rfc3986($key_parts);
        $key = implode('&', $key_parts);
 
        return base64_encode(hash_hmac('sha256', $base_string, $key, true));
    }
 
}