if len(credElements) < 5 {
		return ch, ErrCredMalformed
	}
	accessKey := strings.Join(credElements[:len(credElements)-4], SlashSeparator) // The access key may contain one or more `/`
	if !auth.IsAccessKeyValid(accessKey) {
		return ch, ErrInvalidAccessKeyID
	}
	// Save access key id.
	cred := credentialHeader{
		accessKey: accessKey,
	}
	credElements = credElements[len(credElements)-4:]
	var e error