Secure Channel Establishment via Ephemeral Key Exchange
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Solution Overview
Problem
Establishing a secure communication channel between a client and a remote server through an intermediate entity is vulnerable to eavesdropping and man-in-the-middle attacks, especially when a permanent secret key is shared among multiple clients, compromising confidentiality and secrecy.
Innovation Solution
The method involves mutual authentication using long-term and ephemeral key pairs, where the client and server generate a common secret key based on ephemeral keys via the Diffie-Hellman protocol, ensuring that even if the permanent secret key is compromised, the secure channel remains secure, and the gateway cannot access plaintext data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the gateway decrypts and re-encrypts data between client and server, then protocol translation is enabled, but data confidentiality is compromised
Solution Approach 1:
The patent introduces a certificate authority as an intermediary that issues digital certificates to both client and server. This allows the gateway to verify identities and establish secure connections without needing to decrypt the actual communication data, thus maintaining confidentiality while enabling protocol translation through the gateway.
Solution Approach 2:
The patent segments the authentication and encryption processes into separate components: identity verification through certificates, key exchange through ephemeral keys, and data encryption through separate session keys. This allows the gateway to handle protocol translation at the authentication layer without accessing plaintext data at the application layer.
2Ease of operation
If a permanent secret key is shared among multiple clients, then authentication is simplified, but security is weakened
Solution Approach 1:
The patent transitions from static permanent secret keys to dynamic ephemeral keys that are generated temporarily for each communication session. This allows clients to authenticate using their permanent certificates while establishing unique session-specific encryption keys, maintaining operational simplicity while significantly improving security against key compromise.
Solution Approach 2:
The patent changes the cryptographic parameters from long-term static keys to short-term ephemeral keys for the actual communication channel. The permanent secret key remains for identity verification, but the encryption uses dynamically generated keys that are discarded after use, thus maintaining ease of authentication while enhancing security.
3Adaptability or versatility
If the gateway acts as an intermediate entity, then communication between client and server is enabled, but the system becomes vulnerable to man-in-the-middle attacks
Solution Approach 1:
The patent introduces a certificate authority as a trusted intermediary that issues digital certificates to both client and server. The gateway verifies these certificates to authenticate the identities of communicating parties, enabling the gateway to act as an intermediate routing entity while preventing man-in-the-middle attacks through cryptographic verification of identities.
4Device complexity
If the permanent secret key is compromised, then all clients sharing the same key are vulnerable, but key management is simplified
Solution Approach 1:
The patent implements a dynamic key hierarchy where permanent secret keys are used only for identity verification through digital signatures, while ephemeral session keys are generated for each communication. This separation means that compromise of a permanent key does not expose session encryption keys, maintaining simple key management structure while improving confidentiality.
Solution Approach 2:
The patent segments the cryptographic key system into two distinct functions: authentication keys (permanent) and encryption keys (ephemeral). This segmentation ensures that compromise of authentication keys does not affect the security of encrypted communications, as different key pairs are used for each function.
Data Source
AI summary
The present invention provides a method for establishing a secure communication channel between a client (C) and a remote server (S), said client (C) and remote server (S) exchanging data through an intermediate entity (G), said client (C) having a long-term key pair (skc,pkc), said remote server generating an ephemeral key (sks,pks), the method comprising a mutual authentication step wherein the client (C) sends a public key (pkc) of said long-term key pair (skc, pkc) and the proof that said public key (pkc) is valid to the server (S), and wherein the remote server (S) sends the public key (pks) of said ephemeral key pair (sks,pks) to the client (C). The client (C) generates an ephemeral key pair (skCc,pkCc) and sends the public key (pKcc) of said ephemeral key pair (skcc,pkcc) to the server (S) so as to generate a secret common to the client (C) and to the remote server (S) for opening the secure communication channel.