Blind Signature Generation Using Homomorphic Encryption
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Solution Overview
Problem
Existing digital signature methods do not provide anonymity, allowing third parties to verify messages, which is a security concern in information transmission.
Innovation Solution
An apparatus and method for generating a blind signature that uses homomorphic encryption to encrypt data, allowing for the creation of a digital signature that maintains message confidentiality and anonymity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital signature is used to verify message authenticity, then message integrity is improved, but message confidentiality deteriorates because third parties can verify the message
Solution Approach 1:
The patent segments the digital signature process into two independent parts: (1) signature generation on encrypted message using homomorphic encryption, and (2) signature verification on decrypted message. This allows the signature operation to be performed without exposing the message content to third parties, thus maintaining confidentiality while ensuring integrity.
Solution Approach 2:
Homomorphic encryption serves as an intermediary that enables signature operations to be performed on encrypted data. The encryption scheme allows the signer to process the encrypted message and generate a signature without decrypting it, preventing information leakage to third parties while maintaining the ability to verify authenticity.
2Reliability
If homomorphic encryption is used to maintain message confidentiality, then message security is improved, but system complexity increases
Solution Approach 1:
The patent employs a universal homomorphic encryption scheme that can handle both encryption and signature generation operations within a single cryptographic framework. This multi-functional approach consolidates multiple cryptographic operations into one system, reducing overall complexity compared to using separate encryption and signature schemes.
Solution Approach 2:
The patent utilizes specific mathematical parameters and structures in the homomorphic encryption scheme (such as chosen ciphertext security parameters and specific group elements) that optimize the balance between security and computational efficiency. By carefully selecting and adjusting cryptographic parameters, the system achieves strong security guarantees while managing complexity.
Data Source
AI summary
An electronic apparatus includes a communication apparatus communicating with an external apparatus, a memory storing a message, and a processor generating a digital signature for the message, wherein the processor generates a first signature ciphertext and a message ciphertext by encrypting each of first signature information and the message by using a homomorphic encryption public key, obtains encrypted third signature information generated using second signature information, an element value corresponding to the second signature information, the first signature ciphertext, and the message ciphertext, and calculates a first digital signature value included in the digital signature by using the first signature information and the second signature information, calculate a second digital signature value included in the digital signature by decrypting the encrypted third signature information, and generate the digital signature by using the calculated first digital signature value and second digital signature value.