XIN Light Client Infinity Foundation May, 2017, v1 Content: 1. Client Overview 2. Lightweight Client 3. Privacy 4. Expandable 5. Client Versions 1. Client Overview The classic Bitcoin approach is essentially a way to synchronize a distributed system through common transaction logs. It requires that each network node store the full copy of the transaction history. Obviously this does not scale well, since eventually not every node will be able to store the full history. There are different ways to mitigate this â€“ a simplified payment verification procedure that allows storage of only that data essential for a given node; off-chain transactions; bidirectional payment tunnels; reducing blockchain bloat; working directly with the system state. With the simplest approach, where all nodes are equal at Genesis block, centralization may emerge as low-capacity nodes have to rely on full, high-capacity nodes that can afford to store the full blockchain. Of course, emerging centralization brings trust issues, since lightweight nodes have to trust the full nodes and can become a victim of a rogue full node. However, there are ways to mitigate this, such as polling several nodes, maintaining trusted nodes lists, and so on. XIN provides a new structure for these tasks by leveraging the peerexplorer. The foundation maintains a base of trusted high capacity servers to ensure sufficient nodes available for clients. A node rating algo is used to rank the top nodes, count in the CPU load, processors available and more node metrics in realtime to 'load-balance' the client requests for optimal performance. 2. Lightweight Client (Smart Wallet) XIN platform enforces an approach that might at first seem extreme to a classic cryptocurrency advocate. XIN smart wallets do not download the blockchain at all, instead relying on full nodes for payment verification and network interaction. Each transaction is digitally signed to verify that someone who knows the secret passphrase of the originating account authorized the transaction. For enhanced security, the client utilize offline transaction signing, the purpose of which is to protect the secret passphrase from exposure to the Internet. This brings several advantages. The user does not have to download the blockchain anymore, which means the application itself stays very small and extensible. It does not broadcast secret keys through the network, all data is signed locally on your device. In addition the client provides several connection types to act also as a classical client, connecting to the users local node. The connection choices are: Automatic, Manual, Localhost, SSL and Foundation. This gives a broad range of usages, from classic private node to fully automatic, load-balanced usage. The lite client is available for Windows, Linux and MacOS. It does not require an installation process, as it utilizes modern web technologies. 3. Privacy To enhance connection privacy, the client selects different nodes for each request made on a node. This has two advantages, first one is privacy. Due to this dynamic node IP 'jumps' nodes are less able to collect request data (which isn't the case in general) from connected clients. Secondly the load created by lots of clients is distributed to many nodes in realtime. 4. Expandable Since the client utilizes modern web technologies, it is very easy to add additional features on the fly. Please see extensions and services for more informations. 5. Client Versions Currently the client is built as an Online (Web-based) wallet with no installation needed. Combining with Electron this can be built to a full, self-contained desktop wallet for Windows, Linux and MacOS. An a mobile (Android) version is in development.