Group Public Key Encryption with Individual Member Keys
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Solution Overview
Problem
Existing systems for electronic communication face inefficiencies in securely distributing and identifying cryptographic keys, especially in multi-user networks where generating and managing large volumes of public and private key pairs becomes time-consuming and less secure when dealing with hundreds or thousands of recipients.
Innovation Solution
A system and method for public key encryption in groups, where a group leader generates a group public key and personalized decryption keys for each member, allowing each member to decrypt messages independently using their unique private key, while the group leader retains the master private key and can identify unauthorized key disclosure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual public and private key pairs are generated for each group member to maintain security, then security is improved, but the time required to generate and manage keys increases significantly
Solution Approach 1:
The patent segments the key management system into a group-level key pair (for encryption and general decryption) and individual member key pairs (for identification and verification). This segmentation allows the group to share a common encryption key while maintaining individual accountability through unique member keys, thus reducing the overall key management burden while preserving security.
Solution Approach 2:
The patent introduces a group leader as an intermediary who manages the group key pair and coordinates key distribution. The group leader acts as a mediator between the encryptor and group members, handling key generation, distribution, and revocation, thereby simplifying the key management process for all members while maintaining security through centralized control.
2Device complexity
If a single shared key is used for symmetric encryption among all users, then key management becomes simpler, but security is compromised when key disclosure occurs
Solution Approach 1:
The patent segments the single shared key approach into a group encryption key (shared by all members for decrypting group messages) and individual member keys (unique to each member for identification). This segmentation maintains the simplicity of shared key management for encryption while adding individual keys to preserve security and enable identification of key disclosers.
Solution Approach 2:
The patent applies local quality by making the decryption capability shared (group key) while making the identification capability local and unique (individual member keys). Each member has the same ability to decrypt group messages but has a unique key that can identify them if disclosure is detected, thus combining simplicity with security.
3Ease of operation
If multiple key pairs are generated for hundreds or thousands of recipients, then each recipient can independently decrypt messages, but the system becomes increasingly time-consuming and less efficient
Solution Approach 1:
The patent segments the decryption capability into a shared group decryption key (allowing all members to independently decrypt) and individual identification keys (for tracking and accountability). This segmentation enables independent decryption for all members without requiring unique encryption keys for each, thus maintaining ease of operation while improving efficiency by reducing the number of key pairs that need to be managed.
Solution Approach 2:
The patent makes the group encryption key universal, allowing any group member to use it for decrypting messages encrypted for the group. This universal key eliminates the need for multiple unique encryption keys while the individual member keys provide the necessary identification and accountability, thus achieving both independent decryption capability and system efficiency.
4Reliability
If individual private keys are used for recipient identification, then security and integrity are maintained, but the complexity of managing and distributing keys increases
Solution Approach 1:
The patent segments the identification function from the encryption/decryption function by using individual member keys solely for identification and verification, while the group key handles encryption and decryption. This segmentation simplifies key distribution as members only need to securely receive their individual identification keys from the group leader, while the group key is managed centrally, reducing overall complexity.
Solution Approach 2:
The group leader acts as an intermediary who manages the distribution and revocation of individual member keys. This intermediary approach simplifies key distribution complexity by centralizing key management operations, allowing the system to maintain accurate recipient identification without each participant needing to directly manage their own key distribution.
Data Source
AI summary
A system is comprised of a user and a group, wherein the group is comprised of a group leader and a group of M members where M is equal to or greater than one. The group leader generates a group public key and a group leader “master” private key. The group leader creates a personalized watermarked or decryption key, also referred to as an individual private key, for each group member. The individual private key uniquely identifies each group member. The group leader distributes the individual private keys to each of the group members. Each group member receives from a user a message encrypted using the group public key. Each of the group members uses its individual private key to decrypt the encrypted message sent by the user to the group.