// Expects key type of []byte for both signing and validation
type SigningMethodHMAC struct {
	Name       string
	Hash       crypto.Hash
	HasherPool sync.Pool
}

// Specific instances for HS256, HS384, HS512
var (
	SigningMethodHS256 *SigningMethodHMAC
	SigningMethodHS384 *SigningMethodHMAC
	SigningMethodHS512 *SigningMethodHMAC
)

const base64BufferSize = 64 * humanize.KiByte

var (
	base64BufPool sync.Pool

	jp := new(jwtgo.Parser)
	jp.ValidMethods = []string{
		"RS256", "RS384", "RS512",
		"ES256", "ES384", "ES512",
		"HS256", "HS384", "HS512",
		"RS3256", "RS3384", "RS3512",
		"ES3256", "ES3384", "ES3512",
	}

	keyFuncCallback := func(jwtToken *jwtgo.Token) (interface{}, error) {
		kid, ok := jwtToken.Header["kid"].(string)
		if !ok {