Introduction

SKDP is a next-generation protocol designed to solve one of the most challenging problems in cryptography: secure key distribution. As the Internet has evolved into a global communications medium used by billions, traditional methods based on a single pre-shared symmetric key are increasingly vulnerable. In such systems, if a device or a server's key is compromised, all encrypted communications; past, present, and future, can be decrypted by an attacker. Furthermore, these systems lack forward secrecy, meaning that the exposure of a session key may reveal all historical communications.

Statement of the Problem

Traditional key distribution schemes using pre-shared symmetric keys suffer from significant issues:

Scalability: A single pre-shared key or a centralized key database creates a bottleneck, and its compromise can endanger the entire network.
Single Point of Failure: If an attacker captures a device's embedded key or the server's key database, all messages can be instantly decrypted.
Lack of Forward Secrecy: Without mechanisms to refresh keys, the capture of a session key can expose all previous communications.

The SKDP Solution

SKDP proposes a novel approach that uses strong symmetric cryptographic primitives with longer key lengths, making the underlying problem far more computationally expensive and potentially infeasible to break. In SKDP:

Pre-shared keys are used primarily for authentication and for encrypting secret tokens exchanged between the server and the client.
Ephemeral session keys, which are derived from these secret tokens, are used to encrypt the actual message streams. This ensures that the compromise of a device's embedded key or the server's key database does not compromise past communications.
Forward secrecy is achieved because each session is encrypted with a unique, ephemeral key that cannot be derived from the pre-shared key alone.

Hybrid Security Model

SKDP can be combined with a quantum secure protocol (such as QSMP) that periodically injects fresh entropy into the system. This hybrid approach not only enhances the overall security but also provides true long-term security, even in the face of quantum computing advancements.

Scalability and Network Management

One of the key strengths of SKDP is its scalability. Using a single master key, SKDP can securely manage millions of devices. The master key is used to derive branch keys, and from each branch key, individual device keys are derived. This hierarchical key derivation allows:

Any branch to securely connect with any client on another branch, provided they share the branch identification.
A tree-like derivation structure where a branch key is derived from the master key, and each leaf node's key is derived from its branch key.

This approach minimizes the risk associated with a centralized key database and reduces the impact of any individual key compromise, making SKDP suitable for large-scale networks across local institutions and enterprise environments.

Applications

SKDP is ideal for various applications, such as:

Institutional transaction-based protocols, where embedded keys can be stored on debit or credit cards.
Communication systems that distribute keys via pluggable memory-storage devices, with a central hub managing secure connections.
Large-scale networks that require the secure management of millions of devices via a single master key.

Conclusion

By leveraging robust symmetric cryptographic primitives and a scalable, hierarchical key derivation scheme, SKDP provides forward secrecy and resolves many of the inherent vulnerabilities in traditional pre-shared key systems. Its design mitigates the risk of mass compromise and ensures that even if a device's key or a server's key is exposed, past communications remain secure. SKDP represents a significant advancement in secure key distribution, offering long-term security in an era of rapidly evolving cryptographic threats and quantum computing.

License

Author: John G. Underhill

Date: 2025-02-10