"strings"
	"time"

	"github.com/minio/minio-go/v7/pkg/tags"
	"github.com/minio/minio/internal/crypto"
	xhttp "github.com/minio/minio/internal/http"
	xxml "github.com/minio/xxml"
)

// Returns a hexadecimal representation of time at the
// time response is sent to the client.
func mustGetRequestID(t time.Time) string {
	return fmt.Sprintf("%X", t.UnixNano())
}

	regionBytes := sumHMAC(date, []byte(region))
	service := sumHMAC(regionBytes, []byte(stype))
	signingKey := sumHMAC(service, []byte("aws4_request"))
	return signingKey
}

// getSignature final signature in hexadecimal form.
func getSignature(signingKey []byte, stringToSign string) string {
	return hex.EncodeToString(sumHMAC(signingKey, []byte(stringToSign)))
}

// Check to see if Policy is signed correctly.

An exponent value exp scales the mantissa (integer and fractional part) by 10<sup>exp</sup>.
</p>

<p>
A hexadecimal floating-point literal consists of a <code>0x</code> or <code>0X</code>
prefix, an integer part (hexadecimal digits), a radix point, a fractional part (hexadecimal digits),
and an exponent part (<code>p</code> or <code>P</code> followed by an optional sign and decimal digits).

An exponent value exp scales the mantissa (integer and fractional part) by 10<sup>exp</sup>.
</p>

<p>
A hexadecimal floating-point literal consists of a <code>0x</code> or <code>0X</code>
prefix, an integer part (hexadecimal digits), a radix point, a fractional part (hexadecimal digits),
and an exponent part (<code>p</code> or <code>P</code> followed by an optional sign and decimal digits).