Encryption Processing System Using Distributed Key Fragmentation
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Solution Overview
Problem
Existing secret sharing techniques require a highly reliable organization to generate and manage common keys, making them vulnerable to key leakage and management issues.
Innovation Solution
A system where secret information is encrypted using public keys of multiple party devices, with only authorized devices able to restore the secret information by multiplying their public keys to generate a synthesis key, eliminating the need for a highly reliable organization to manage the common key.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a highly reliable organization generates and manages a common key for secret sharing, then the secret information can be restored when needed, but the system becomes vulnerable to key leakage and requires trusting a single organization
Solution Approach 1:
The patent segments the common key into multiple key fragments distributed to different party devices. Each fragment is encrypted with a different public key, so no single party can reconstruct the common key alone. This eliminates the need to trust a single organization while maintaining the ability to restore secret information when sufficient fragments are collected.
Solution Approach 2:
The patent introduces a mediator device that facilitates the secure distribution and management of key fragments without requiring the parties to trust each other directly. The mediator enables the restoration process by coordinating the collection of sufficient key fragments while maintaining security through cryptographic protocols.
2Reliability
If multiple party devices hold key fragments for secret sharing, then the reliance on a single organization is reduced, but the complexity of key management and restoration increases
Solution Approach 1:
Each party device independently manages its own key fragment using its private key for decryption and its public key for encryption. The devices autonomously participate in the restoration process by contributing their fragments when needed, eliminating the need for complex centralized key management while maintaining security.
Solution Approach 2:
The patent implements a feedback mechanism where the mediator device tracks which key fragments have been distributed and monitors the restoration process. This feedback system automatically coordinates the collection of sufficient fragments without requiring complex manual management, reducing the perceived complexity for users.
3Quantity of substance
If secret information is encrypted with a common key and the key is fragmented, then the amount of data to be shared is reduced, but the system requires a highly reliable organization to generate the common key
Solution Approach 1:
The patent segments both the secret information encryption and the key management into distributed components. The common key is fragmented and distributed to multiple parties, each encrypting their fragment with their own public key. This maintains the data reduction benefit of encapsulation while eliminating the need to trust a single key-generating organization.
Solution Approach 2:
The patent creates a multi-functional system where each party device can both encrypt its key fragment and participate in the restoration process. The mediator device serves multiple functions including distribution coordination, fragment collection, and restoration facilitation, making the system universally applicable without requiring specialized trusted organizations.
Data Source
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AI summary
An encryption processing system includes: an encrypted data generation device that encrypts secret information; party devices of a first number, the party devices each including a key pair of a public key and a private key; and a fragment combining device that collects and combines pieces of fragment information shared by the party devices of the first number, wherein the encrypted data generation device includes: a first generation unit that generates synthesis keys of a third number by performing, a third number of times, a process for selecting public keys of a second number to be used for key restoration from public keys of the first number to generate the synthesis key, the third number being a number of combinations of selecting the public keys of the second number from the public keys of the first number; a second generation unit that generates an intermediate text from confidential texts of a fourth number generated by encrypting each piece of the secret information by using the public keys of the party devices of the fourth number having decryption authority for the secret information among the party devices of the first number, and generates secret information ciphertexts of the third number by further encrypting the intermediate text using each of the synthesis keys; and a first public unit that makes public encrypted data including the secret information ciphertexts of the third number and a first signature relating to the secret information ciphertexts of the third number, each of the party devices includes: a first verification unit that verifies validity of the encrypted data by using the first signature; a third generation unit that generates, when the validity has been verified, by using a private key included in an own party device, decryption key fragments of a fifth number, and generates second signatures of the fifth number respectively corresponding to the decryption key fragments of the fifth number, the fifth number being a number of combinations of selecting the party devices of a number obtained by subtracting one from the second number from among the party devices of a number obtained by subtracting one from the first number; and a second public unit that makes public the decryption key fragments of the fifth number and the corresponding second signatures, the fragment combining device includes: a second verification unit that verifies validity of the decryption key fragments of the fifth number by using the decryption key fragments of the fifth number and the corresponding second signatures; a fourth generation unit that generates a decryption key by combining decryption key fragments of the second number corresponding to any one of the secret information ciphertexts of the third number among the decryption key fragments of the fifth number that are made public by each of the party devices of the first number, and generates the intermediate text by decrypting the secret information ciphertext corresponding to the generated decryption key with the generated decryption key; and a third public unit that makes public the intermediate text generated by the fourth generation unit, and each of the party devices further includes: a decryption unit that decrypts, when the own party device has the decryption authority, the intermediate text that is made public by the third public unit using the private key included in the own party device, and restores the secret information.