SIP Signalization in the PSTN:
The Underlying BlockNum Communication Protocol

The mathematical and network complexity of traditional blockchain is partly based on the overall vulnerabilities built into the public Internet which is base communications system of blockchains. By its very design, security on the Internet has to deal with multiple points of entry and the ability to communicate directly with Internet components by both authorized and non-authorized parties.  This means that security has to deal with multiple point intrusion potential with each component.

However the BlockNum block chain is not connected directly to the Internet but rather relies on traditional SIP signalization which is not subject to public intrusion and which contains proprietary SIP headers which support the proprietary BlockNum protocol. As will be detailed further, the communication and protocols provide BlockNum transactions with unprecedented security, high transaction speed and very low energy consumption.

SIP-based messaging is the underlying communication protocol for all BlockNum transactions.

BlockNum utilizes the standard SIP functionality while adding its own enhancements. SIP messages are highly secure and pass between components only via port 5061. All other TCP/UDP ports are blocked. SIP-based distribution of node access credentials via Transport Layer Security (TLS) cryptographic protocol communications security using MD5 algorithm hash function and 128-bit hash value.

The SIP-based node registration on the network is a standard stepped process which uses standard methods and sequence messaging (messages numbered from 100 to 500) between 2 SIP nodes but adapted for use in a blockchain and sequential transaction numbering.

For any given BlockNum transaction, SIP headers are customized to transaction and are updated as the transaction proceeds while maintaining common message components such as parties to the transaction and the transaction being attempted.

As each step of the transaction proceeds, the message evolves appropriately by step , e.g.SIP-based Token transaction confirmation

  • SIP-based Token Acquisition transaction
  • SIP-based Full Node synchronisation process
  • SIP-based Token conversation
  • Cryptocurrency wallet transfer

Once the BlockNum SIP server creates the unique session ID for a given transaction, this ID will stay the same until the transaction is complete (successfully or as a failed transaction). However, as the message passes from BlockNum node to node, the message is recreated by the respective node and information is added to the SIP header which is the added history of the transaction as it proceeds through the BlockNum Network.

This creates the condition for a back to back user agent as a logical network element in the SIP BlockNum application which is an essential element of BlockNum creating a blockchain transaction. It is therefore highly secure and by its inherent structure, each node becomes a firewall

B-SIP is responsible for all secured communication between all BlockNum nodes in the network only involved the blockchain transaction in the signaling portion establish between two-node directly (unicast).

B-SIP allows blockchain information exchange within existing secure session between 2 nodes

The message involves confirming the existence of a wallet number (the BlockNum account number based on a user’s telephone number), an available balance, creation of a new wallet, etc.  Also the B-SIP protocol is responsible of creating a block number for a transaction, locking down the next block number with a Session ID.

Just like SIP, B-SIP employs design elements similar to the HTTP request/response transaction model.

Each transaction consists of a client request that invokes a particular method or function on the server and at least one response. B-SIP reuses most of the header fields, encoding rules and status codes of HTTP, providing a readable text-based format that contains specific data for each blockchain transaction.

Like in standard SIP, the network elements (BlockNum Server, SBC, Token Proxy, Full Node and Super Node) that use the blockchain Session Initiation Protocol for communication between them are called SIP user agents.

Each user agent (UA) performs the function of a user agent client (UAC) when it is requesting a service function, and that of a user agent server (UAS) when responding to a request.

Thus, any two B-SIP BlockNum nodes may in principle, operate without any intervening SIP infrastructure. However, for network operational reasons, for provisioning public services to users and for directory services, SIP defines several specific types of network server elements.

Each of these service elements also communicates within the client-server model implemented in user agent clients and servers.

All Network elements of the BlockNum network are based on Kamailio’s Session Border Control and Proxy as well as Asterisk Back-to-Back User Agent and PSTN Gateway

More info on B-SIP protocol in the white paper