Identity-Based Decryption via Intermediary Key Distribution

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Solution Overview

Problem

Existing authentication methods, such as public key cryptography and identity-based encryption, face challenges in verifying identities and distributing keys, which can be costly, time-consuming, and error-prone, and do not effectively encrypt content prior to delivery.

Innovation Solution

The method involves an identity-based encryption applet that generates a random key to encrypt message content, which is then sent with authentication information to a decryption service provider, who decrypts and forwards the key to the recipient's decryption applet for secure content decryption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If public key cryptography is used for authentication, then identity verification is achieved, but key distribution becomes costly and time-consuming

Engineering Contradiction:
Improveidentity verificationVSAvoidkey distribution time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts the key generation function from the authentication process itself. A key generation center separately generates private keys for users based on their public identifiers, rather than requiring direct key exchange between communicating parties. This separates key distribution from the authentication protocol, reducing time loss.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a key generation center as an intermediary that facilitates key distribution. This mediator generates private keys for users based on their public identifiers and distributes them through a trusted channel, eliminating the need for direct key exchange between communicating parties and reducing overall distribution time.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If identity-based encryption is implemented, then key distribution is simplified, but system complexity increases

Engineering Contradiction:
Improvekey distributionVSAvoidsystem complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent introduces a key generation center as an intermediary that facilitates key distribution. This mediator generates private keys for users based on their public identifiers and distributes them through a trusted channel, eliminating the need for direct key exchange between communicating parties and reducing overall distribution time.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Users can derive their private keys from their public identifiers through the key generation center without requiring manual key pair generation or exchange. The system automatically handles key derivation and distribution based on user identities, reducing operational complexity for end users.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If traditional authentication methods are used, then implementation is simple, but content encryption is not performed

Engineering Contradiction:
Improveimplementation simplicityVSAvoidcontent encryption
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent merges authentication and encryption functions into a unified identity-based cryptographic system. Users authenticate themselves using their public identifiers, and the same identity information is used to derive encryption keys, combining what were previously separate processes into one integrated system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a multi-functional cryptographic system where public identifiers serve multiple purposes: authentication verification, key derivation, and encryption. This universal approach eliminates the need for separate authentication credentials and encryption keys, maintaining simplicity while adding encryption capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2700189B1Identity-based decryption
Publication Date: 2020.01.22 BLACKBERRY LTD
  • EP2700189B1 patent drawingFigure 1~2
  • EP2700189B1 patent drawingFigure 3~4
  • EP2700189B1 patent drawingFigure 5~7

AI summary

Devices and methods are provided for managing identity-based decryption of digital content. A message sender ("Alice") uses a random key (Krand) to encrypt message content for a message recipient ("Bob"). Then Alice uses the public key of a message decryption service provider ("Carmen") to generate a wrapped key ciphertext comprising the Krand and authentication information associated with Bob. Alice then sends a message text containing the encrypted message content and the wrapped key ciphertext to Bob, who in turn sends the wrapped key ciphertext to Carmen along with his authentication information. Carmen then uses her private key to process the wrapped key ciphertext to decrypt the Krand and Bob' s authentication information. If the authentication information provided by Bob matches the decrypted authentication information, then Carmen sends the decrypted Krand to Bob, who uses it to decrypt the encrypted message content.