ID-Based Encryption Using Symmetric Key Extraction
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Solution Overview
Problem
Existing ID-based cryptography methods are too complex and require excessive calculations, making them unsuitable for small terminals like mobile devices, and they also generate large public keys and ciphertexts, which is inefficient.
Innovation Solution
An ID-based encryption and decryption method that uses a transmitting-side and receiving-side private key to generate a session key, extract a secret key, and perform encryption and decryption using symmetric key-based algorithms, reducing computational load and ciphertext size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing ID-based cryptography employs pairing, then security is ensured, but calculation complexity increases excessively
Solution Approach 1:
The patent extracts only the necessary cryptographic components needed for ID-based encryption, eliminating the complex pairing operations from existing ID-based cryptography. By taking out the essential elements (ID-based key generation and encryption) while removing unnecessary complex operations, the system achieves security without excessive calculation complexity.
Solution Approach 2:
The patent replaces the complex mechanical pairing-based cryptographic system with a simplified system using symmetric key operations. This substitution of the cryptographic mechanism reduces calculation complexity while maintaining security, as symmetric operations are computationally lighter than pairing-based asymmetric operations.
2Reliability
If existing ID-based cryptography uses pairing operations, then encryption security is maintained, but ciphertext size becomes large
Solution Approach 1:
The patent extracts only the essential encryption functionality needed for security, removing the overhead of pairing operations that inflate ciphertext size. By taking out the necessary symmetric key encryption components and eliminating unnecessary cryptographic padding from pairing operations, the system achieves compact ciphertext while maintaining security.
3Productivity
If lattice-based cryptography is used, then calculation performance improves, but parameter sizes become too large
Solution Approach 1:
The patent changes the cryptographic parameters from large lattice-based parameters to smaller symmetric key parameters. By adjusting the parameter size to match the computational capabilities of mobile terminals while maintaining adequate security, the system achieves both good calculation performance and compact parameter sizes.
Data Source
AI summary
Provided are identifier (ID)-based encryption and decryption methods and apparatuses for the methods. The ID-based encryption method includes having, at a transmitting terminal, a transmitting-side private key corresponding to a transmitting-side ID issued by a key issuing server, generating, at the transmitting terminal, a session key using the transmitting-side ID, a receiving-side ID, and the transmitting-side private key, extracting, at the transmitting terminal, a secret key from at least a part of the session key, and encrypting, at the transmitting terminal, a message using a previously set encryption algorithm and the secret key.