Edge CDN Content Re-Encryption Without Private Key Sharing
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Solution Overview
Problem
Large network operators face challenges in moving Content Delivery Network (CDN) caches from the network core to the edge due to infrastructure and resource constraints, and CDN operators are hesitant to trust network operators with their private keys for secure content distribution.
Innovation Solution
Implementing a method and apparatus using proxy re-encryption and homomorphic encryption to securely distribute digital content from CDN operators to user-devices without disclosing private keys, by generating a cryptographic re-encryption key based on a shared session key between the CDN operator and user-device, allowing encrypted content to be re-encrypted and decrypted using standard session-establishment procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If CDN caches are moved from network core to edge locations, then network traffic is reduced and cost savings are achieved, but infrastructure investment and operational complexity increase significantly
Solution Approach 1:
The patent introduces a key management service as an intermediary between CDN operators and network operators. This service manages cryptographic keys and re-encryption operations, allowing CDN content to be securely distributed through network operator infrastructure without requiring CDN operators to directly manage edge location infrastructure. The intermediary abstracts the complexity of edge infrastructure management while enabling traffic reduction benefits.
2Ease of manufacture
If CDN operators use network operator infrastructure at edge sites, then infrastructure investment is reduced, but trust requirements and security concerns increase
Solution Approach 1:
The key management service acts as a trusted intermediary that CDN operators can rely on for secure key management. Instead of directly trusting network operators with their private keys, CDN operators trust the key management service which handles key generation, storage, and re-encryption operations. This intermediary layer resolves the trust dilemma by providing a specialized security service that protects CDN operator interests while enabling use of network operator infrastructure.
Solution Approach 2:
The patent replaces the mechanical/physical trust relationship (CDN operators physically securing their own hardware at edge sites) with a cryptographic trust relationship. Through proxy re-encryption and secure key management, the system ensures that even if network operator infrastructure is compromised, CDN operators' private keys remain secure. The cryptographic mechanisms substitute for physical security measures.
3Ease of operation
If private keys are disclosed to network operators for content distribution, then content delivery is simplified, but security and authentication integrity are compromised
Solution Approach 1:
The patent replaces direct key disclosure with cryptographic proxy re-encryption mechanisms. Instead of network operators receiving CDN operators' private keys, the system uses mathematical transformations that allow content to be re-encrypted for end users without either party needing to know the other's private keys. This cryptographic substitution maintains authentication security while enabling simplified content distribution through the network operator infrastructure.
Solution Approach 2:
The patent extracts the private key from the content distribution process entirely. The key management service generates separate key pairs for CDN operators and end users, and uses proxy re-encryption to transform content encryption without exposing either private key. The private key is taken out of the distribution chain, eliminating the security risk of key disclosure while maintaining distribution functionality.
Data Source
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Figure 2
AI summary
Methods and apparatus are disclosed for enabling digital content from a content provider (12, 5 14) to be provided via a communication network (10) from intermediate digital content stores (16) to user-devices (18). According to one aspect, the method comprises the content provider (12, 14) providing digital content encrypted using a cryptographic encryption key to an intermediate digital content store (16), the cryptographic encryption key being a public key of a key-pair and having an associated private key. In response to a request from a user-device (18) to the content provider (12, 14) for the digital content, a cryptographic session key is shared between the content provider (12, 14) and the requesting user-device (18). The content provider (12, 14) provides to the intermediate digital content store (16) the cryptographic re-encryption key and indications of the requested digital content and of the user-device (18).