Cryptographic Protocol Capability Exchange for Secure Messaging

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Solution Overview

Problem

In cryptographic message exchange between computing devices, such as mobile and desktop systems, the sender often lacks information about the cryptographic protocols supported by the recipient, leading to the use of default algorithms instead of stronger ones that both devices could support, resulting in suboptimal encryption.

Innovation Solution

Implementing a system where mobile devices and desktop computers share and cache cryptographic protocol capabilities, allowing the sender to determine and use the strongest protocols supported by both entities, ensuring secure and efficient encryption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sender uses default cryptographic algorithms (e.g., RC2 or 3DES) when communicating with a new recipient, then compatibility is ensured, but the cryptographic strength is suboptimal

Engineering Contradiction:
Improvecryptographic strengthVSAvoidalgorithm compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies preliminary action by having the recipient include their cryptographic capabilities in advance capability information with outgoing messages. This allows the sender to know the recipient's supported algorithms before communication begins, enabling the selection of stronger algorithms rather than defaulting to conservative options. The capability information is cached and reused for future communications with the same recipient.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by having the recipient provide capability information back to the sender. This feedback loop allows the sender to adjust their cryptographic algorithm selection based on actual recipient capabilities rather than assuming default support. The system continuously updates capability information through ongoing communication exchanges.

Inventive Principle:
Principle #23Feedback

2Reliability

If the sender includes capability information with each message, then the recipient can select stronger algorithms, but the message overhead increases

Engineering Contradiction:
Improvecryptographic strengthVSAvoidmessage data volume
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent reduces message overhead by performing the capability exchange action in advance. Instead of including capability information with every message, the system exchanges capability information during initial communication setup or idle periods, then caches it for future use. This preliminary action eliminates the need for repeated capability transmissions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses copying by caching the recipient's capability information locally at the sender's device. Once the capability information is received, it is stored and reused for multiple future communications without needing to retransmit it. This copying approach significantly reduces the quantity of data that would otherwise need to be exchanged with each message.

Inventive Principle:
Principle #26Copying

3Productivity

If the system caches capability information locally, then algorithm selection is faster, but the system must manage and update cached data

Engineering Contradiction:
Improvealgorithm selection speedVSAvoidcapability management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies self-service by enabling the system to automatically manage its own capability cache without requiring manual intervention. The system autonomously receives capability information, updates the cache, and selects appropriate algorithms based on cached data. This self-managing approach handles the complexity internally while presenting a simple interface to users.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent performs capability caching as a preliminary action that occurs automatically in the background. By pre-caching capability information during idle periods or initial setup, the system prepares the data needed for fast algorithm selection without adding complexity to the actual message processing flow. The caching mechanism handles updates and maintenance automatically.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2375674B1System and method for exchanging cryptographic protocol capabilities
Publication Date: 2014.11.26 BLACKBERRY LTD
  • EP2375674B1 patent drawingFigure 1
  • EP2375674B1 patent drawingFigure 2
  • EP2375674B1 patent drawingFigure 3

AI summary

In some data communication configurations, data received from a sender may need to be viewed or otherwise processed by more than one entity with a corresponding client. For example, a message sent to a corporate email address may be viewed by either or both a mobile device and a desktop device. For the sender to utilize the strongest algorithm or protocol used by the recipient, it would therefore need to know which algorithms or protocols are supported by both the mobile and desktop mail clients. A system and method are provided to enable the mobile device to know about the capabilities of related mail clients associated with the communication address (e.g. email address) and vice versa such that the intersection of the capabilities (i.e. the strongest algorithm or protocol supported by all parties involved) can be chosen and the messages or data cryptographically processed accordingly.