ApaiIO\Request\Util::buildSignature PHP Method

    public static function buildSignature($stringToSign, $secretKey)
    {
        return base64_encode(hash_hmac("sha256", $stringToSign, $secretKey, true));
    }

 public function testSignature()
 {
     $expectedResult = "9hUgcq4Tnuwb9naeMAyL/Xnk070qcbQUfSbWsFBztgM=";
     $this->assertEquals($expectedResult, Util::buildSignature('ABCD', 'EFG'));
 }