End-to-End Content Encryption with Password-Based Key Wrapping
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Solution Overview
Problem
Existing end-to-end encryption (E2EE) systems lack flexibility in sharing access to encrypted content while maintaining data security, as intermediaries can potentially access plaintext content, compromising privacy.
Innovation Solution
Implementing a system where content is encrypted with a key encrypting key (KEK) derived from a password, allowing controlled access through a link and password, using centralized key distribution or decentralized systems, ensuring only authorized consumers can decrypt the content without intermediaries accessing plaintext.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If end-to-end encryption is implemented to prevent intermediary access to plaintext content, then data security is improved, but flexibility in sharing access to encrypted content deteriorates
Solution Approach 1:
The encryption key is segmented into two parts: the content remains encrypted with a content encryption key, and the content encryption key itself is encrypted with a key encrypting key (KEK). This segmentation allows the system to maintain strong end-to-end encryption while enabling controlled key distribution to authorized consumers through the KEK, thus resolving the contradiction between security and sharing flexibility
Solution Approach 2:
A key encrypting key (KEK) is introduced as an intermediary mechanism. The KEK does not decrypt the content directly but serves as a mediator to protect and distribute the content encryption key. This intermediary layer enables authorized consumers to obtain the content encryption key through secure key distribution channels while the actual content remains protected by end-to-end encryption, balancing security requirements with access sharing needs
2Adaptability or versatility
If centralized key distribution is used to enable flexible content sharing, then adaptability is improved, but security against intermediary access deteriorates
Solution Approach 1:
The system adds a hierarchical dimension to key management by introducing two levels of encryption: the content encryption key (CEK) for protecting the actual content, and the key encrypting key (KEK) for protecting and distributing the CEK. This dimensional separation allows centralized distribution of the KEK to multiple authorized consumers while the CEK remains securely protected, enabling flexible sharing without compromising the core end-to-end encryption security model
3Ease of operation
If the encryption key is stored with encrypted content for easy access, then ease of operation is improved, but security deteriorates as intermediaries can access the key
Solution Approach 1:
The content encryption key is extracted from the encrypted content storage location and separately protected by encrypting it with a key encrypting key (KEK). The encrypted content and the encrypted key are stored separately, but both are made accessible to authorized consumers through secure channels. This extraction and separate protection mechanism allows consumers to retrieve both the content and key without intermediaries being able to access the plaintext key, thus maintaining both ease of operation and security
Data Source
AI summary
Presented herein are techniques to implement end-to-end encryption. A method includes, encrypting content C with an encryption key EK to obtain encrypted content C′, generating a key encrypting key KEK based on a password, encrypting the encryption key EK with the key encrypting key KEK to obtain an encrypted encryption key EK′, storing the encrypted content C′ and the encrypted encryption key EK′ such that the encrypted content C′ and the encrypted encryption key EK′ are accessible to a content consumer via a link, sending the link and the password to the content consumer, and in response to a request, received via the link, for the encrypted content C′ and the encrypted encryption key EK′, sending the encrypted content C′ and the encrypted encryption key EK′ to the consumer based on the content consumer being on an access control list.