Security Association Discovery via Embedded PRG Seed
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Solution Overview
Problem
Existing end-to-end key management systems, particularly those using asymmetric public key protocols, face challenges in lawfully discovering and intercepting end-to-end security keys without being detectable, especially in scenarios where the provider is not a participant in the key management transaction.
Innovation Solution
A method involving a pseudo-random number generator (PRG) is embedded in client applications, using a secret random seed associated with client identity to generate session keys, allowing a network operator or provider to recompute and intercept communications without the end-points' knowledge, utilizing techniques like Diffie-Hellman and IBAKE protocols while ensuring compliance with legal requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If end-to-end encryption is implemented using asymmetric public key protocols, then data secrecy and security are improved, but the ability to lawfully discover and intercept security keys is lost
Solution Approach 1:
The system performs preliminary action by embedding a pseudo-random number generator (PRG) with a secret random seed in the client application before the key management transaction occurs. This seed is provisioned by the network operator and used to generate the random secret that is subsequently used in the Diffie-Hellman key exchange. By having the PRG and seed embedded in advance, the network operator can later reproduce the same random secret without participating in or detecting the actual key exchange transaction between end-points.
Solution Approach 2:
The patent introduces an intermediary approach by using the embedded PRG as a mediator between the end-points and the network operator. The PRG takes the secret random seed (provided by the network operator) and generates the random secret that the end-points use for key exchange. This intermediary mechanism allows the network operator to influence the key generation process without being directly involved in the transaction, enabling lawful discovery while maintaining the appearance of end-to-end encryption.
2Loss of information
If a network operator embeds a pseudo-random number generator with a secret seed in client applications, then lawful discovery of security associations becomes possible, but device complexity and trust requirements increase
Solution Approach 1:
The system implements self-service by having the client application automatically use the embedded PRG to generate the random secret for key exchange without requiring manual intervention or complex configuration. The PRG is already embedded in the application with the secret seed provisioned beforehand, so when the application needs to perform key exchange, it simply calls the PRG with the appropriate input (such as a nonce or timestamp) and receives the random secret automatically. This simplifies the user experience while enabling lawful discovery.
3Loss of information
If the network operator can recompute session keys without end-point knowledge, then legal interception capability is improved, but the risk of detection and system compromise increases
Solution Approach 1:
The patent applies copying by creating a copy of the random secret generation capability through the embedded PRG. The network operator obtains a copy of the seed and uses the same PRG algorithm to independently reproduce the random secret that the end-points are using. This copying approach allows the operator to intercept and decrypt communications without needing to directly access the end-points' memory or modify their behavior, thereby reducing detection risk while maintaining interception capability.
Data Source
AI summary
Techniques are disclosed for discovering security associations formed in communication environments. For example, a method for forming a discoverable security association between a first computing device (e.g., a first client) and a second computing device (e.g., a second client) comprises the following steps. The first computing device is provided with a seed that is used by the first computing device to generate a secret that is used by the first computing device to compute a key for use in securing communications with the second computing device. The secret is re-computable based on knowledge of the seed and the key is re-computable based on knowledge of the secret such that a third computing device (e.g., an intercepting server) can use the re-computed key to intercept communications between the first computing device and the second computing device unbeknownst to the first computing device and the second computing device. By way of example, the key may be a result of an identity based authenticated key exchange.