Mobile Data Protection via Server-Side Key Segmentation
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Solution Overview
Problem
Existing mobile device security measures, such as encryption using a content protection key or asymmetric key pairs, are vulnerable if the user's password is compromised, allowing unauthorized access to sensitive information even when the device is locked.
Innovation Solution
A Data Protection Module on the mobile device receives a secret key from a trusted party for secure encryption and decryption of data, using it to create a new key that is deleted after encryption, ensuring that even the user's password cannot decrypt the data, and re-establishing the key when the device is in a safe area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encryption using a content protection key is used to protect data on a mobile device, then data security is improved, but the system becomes vulnerable if the user's password is compromised
Solution Approach 1:
The patent introduces a server as an intermediary that holds the master key separately from the mobile device. The mobile device stores only encrypted data and a reference to the master key, while the server stores the actual master key. This separation means that even if the device is compromised or the user divulges their password, the attacker cannot access the master key or decrypt the data without server authorization.
Solution Approach 2:
The encryption system is segmented into multiple components: a master key stored on the server, individual encryption keys derived from the user's password for each device, and the actual data encrypted on the device. This segmentation ensures that no single component contains all the information needed to decrypt data, distributing security responsibilities across multiple trusted parties.
2Reliability
If a temporary symmetric key is generated from the user's password to encrypt the content protection key, then data protection is improved, but the key management complexity increases
Solution Approach 1:
The system automatically generates and manages the temporary symmetric key from the user's password without requiring manual intervention. When the user inputs their password, the system automatically derives the encryption key, encrypts the content protection key with it, and then automatically deletes the temporary key from memory. This self-service approach eliminates the need for users to manually manage keys while maintaining strong security.
Solution Approach 2:
The patent uses temporary symmetric keys that are created solely for the purpose of encrypting the content protection key and then immediately deleted. These disposable keys serve their purpose once and are then discarded, eliminating the need for long-term key storage on the device and reducing the attack surface for persistent key theft.
3Reliability
If the private key is encrypted using the temporary symmetric key generated from the user's password, then data protection while locked is improved, but the system remains vulnerable if the password is divulged
Solution Approach 1:
The server acts as an intermediary that holds the master key separately from the mobile device. The mobile device stores only encrypted data and a reference to the master key, while the server stores the actual master key. This separation means that even if the device is compromised or the user divulges their password, the attacker cannot access the master key or decrypt the data without server authorization.
Solution Approach 2:
The encryption system is segmented into multiple components: a master key stored on the server, individual encryption keys derived from the user's password for each device, and the actual data encrypted on the device. This segmentation ensures that no single component contains all the information needed to decrypt data, distributing security responsibilities across multiple trusted parties.
Data Source
AI summary
Methods and systems are disclosed for protecting data on a mobile device. A data protection module on the mobile device receives a transmission including a secret key. The secret key is used in encrypting data on the device and is then deleted. Subsequent to an event detectable to the mobile device, the data protection module receives another transmission including said secret key. The secret key is then used to decrypt the encrypted data.