CryptoPassphrase  Check-in [958a05efc9]

    func hasSite(_ name: OFString) -> Bool {
        return (storage[name] != nil)
    }

    func length(forSite name: OFString) -> size_t {
        guard let site = storage[name] else {
            OFInvalidArgumentException().throw()
            abort()
        }

        return (site[SiteStorage.lengthField] as! OFNumber).sizeValue
    }

    func isLegacy(site name: OFString) -> Bool {
        guard let site = storage[name] else {
            OFInvalidArgumentException().throw()
            abort()
        }

        return (site[SiteStorage.legacyField] as! OFNumber).boolValue
    }

    func keyFile(forSite name: OFString) -> OFString? {
        guard let site = storage[name] else {
            OFInvalidArgumentException().throw()
            abort()
        }

        let keyFile = site[SiteStorage.keyFileField]
        if keyFile is OFNull {
            return nil
        }