Keys

Sync keys are 20-byte strings that are randomly generated using /dev/random (on Mac and Linux) and the Crypto API (on Windows). This approach is significantly more secure than a login/password combination.

Transfer Protocols

AFILogistics Cloud Backup uses both TCP/IP and uTP to ensure your data can move within and across complex network configurations while making sure not to get in the way of your other network traffic like VoIP calls, video chats or streaming content.

The uTP protocol is a peer-to-peer (B2B) protocol. This protocol is very effective for transferring large files across multiple devices, and is very similar to the powerful protocol used by applications like µTorrent and BitTorrent. The data is transferred in pieces between devices, and Sync works to optimize download and upload speed during the process.

The devices you setup to sync are connected directly using UDP, NAT traversal and UPnP port mapping. Relay and tracker servers are also provided as additional methods to ensure connectivity. Devices on the same local network will use the LAN, bypassing the Internet for faster synchronization.

Data Transmission Security

AFILogistics Cloud Backup was designed with privacy and security in mind. The system uses SRP for mutual authentication and for generating session keys that ensure Perfect Forward Secrecy. All traffic between devices is encrypted with AES-128 in counter mode, using a unique session key. Modification requests are all verified using Ed25519 signatures, and only systems with read & write keys can generate valid modification requests.

Paired Connection Discovery

AFILogistics Cloud Backup uses a few different methods to connect paired devices, or peers as they are sometimes called. AFILogistics Cloud Backup attempts all methods concurrently and uses the best available. Methods include:

• Local peer discovery – All peers inside local network are discovered by sending broadcast packets. If there are peers with the same key they respond to the broadcast message and connect.
• Peer exchange (PEX) – When two peers are connected, they exchange information about other peers they know.
• Known hosts (folder settings) – If you have a known host with a static ip:port, you can specify this in Sync client, so that it connects to the peer using this information.
• AFILogistics Cloud Backup tracker – AFILogistics can use a unique specific tracker server to facilitate peer discovery. The tracker server sees the combination of SHA1(key):ip:port and helps peers connect directly. The tracker also acts like a STUN server and can help do a NAT traversal for peers so that they can establish a direct connection even behind a NAT.
• DHT – Sync uses DHT to distribute information about itself and obtain the information about other peers with this secret. AFILogistics Cloud Backup sends SHA1(Secret):ip:port to DHT to announce itself and will get a list of peers by asking DHT for the following key SHA1(Secret).

Traffic Relay

There are rare cases when peers can’t talk directly. This usually happens when devices are in an office behind strong firewalls. In such a case AFILogistics Cloud Backup provides a relay server to route traffic between peers. All traffic is AES encrypted with your key, so there is no chance for us to see any of your data. Users can opt out of this option.