Enhancing Advertising Privacy with Trusted Execution Environments

As digital advertising continues to evolve, the importance of privacy cannot be overstated. Mozilla has taken a bold step towards safeguarding user data by acquiring Anonym, a pioneering ad tech infrastructure designed to enhance privacy standards in the advertising industry. In this blog post, we explore how Trusted Execution Environments (TEEs) play a critical role in this venture.

Introduction to Trusted Execution Environments (TEEs)

A Trusted Execution Environment (TEE) is a secure platform built to process sensitive information, protecting it from unauthorized access and modifications. It functions as a secure enclave, which is a shielded memory portion that processes confidential data safely, even if the broader system is compromised.

Why Choose TEEs for Advertising?

• Confidentiality: TEEs ensure that data remains encrypted and inaccessible outside the secure enclave, keeping sensitive information protected at all times.
• Attestation: TEEs provide cryptographic proof of the system’s identity and code execution, allowing other systems to verify the trustworthiness of the TEE before interacting with it.

With TEEs, Anonym eliminates the possibility of users’ personal data being shared among advertisers and ad networks. By encrypting the data and processing it within the TEE, Anonym ensures that insights can be derived without creating cross-site behavioral profiles based on individual user data.

Implementation of TEEs in Anonym’s System

Anonym leverages Intel SGX-based TEEs, a widely researched and deployed technology, supported by Microsoft Azure. Here is how TEEs are implemented in our advertising applications:

• Anonym develops a tailored algorithm for each advertising use case. For example, we customize our attribution algorithm to suit the advertiser’s needs and ensure privacy through differential privacy techniques.
• Partners receive detailed documentation and source code access through Anonym’s Transparency Portal. This process, known as binary review, allows partners to verify and approve the code before any data processing.
• Each data processing task begins with the creation of an ephemeral TEE, into which partners’ encrypted data is loaded.
• Through attestation, the TEE verifies its identity and code integrity, ensuring only approved operations proceed.

Ensuring Control and Transparency

Anonym’s system offers distinct advantages by establishing a transparent and controlled environment for data processing:

• No Surprises: Partners have clear visibility on how data will be handled, with consistent operations programmed in advance.
• Accountability: Our partners maintain the ability to revoke Anonym’s data processing privileges at any time.
• Secure Logging: We provide logs that capture entries whenever customers’ data is processed, ensuring real-time visibility into data access.

Executing TEEs in Advertising Use Cases

When a specific advertising application is executed, the process begins with an “ephemeral TEE” that processes the encrypted data:

1. The encrypted data is brought within the TEE’s secure memory.
2. The TEE verifies its cryptographic identity and integrity through attestation.
3. If verification is successful, data decryption occurs, and the specified computation is performed.
4. Post-completion, the TEE is dismantled, and the data within it is destroyed.
5. The aggregated, anonymized results are then shared, protecting data subjects from re-identification.

This approach ensures both the security and privacy of the data being processed, while empowering advertisers to gain valuable insights without compromising user privacy.

Conclusion

With its robust application of Trusted Execution Environments, Anonym sets new benchmarks in delivering privacy-first digital advertising. By prioritizing transparency and control, Mozilla and Anonym together provide advertisers with the confidence to process data ethically, harnessing insights without infringing on user privacy. Stay tuned for our next post, which will delve further into how Anonym’s Transparency Portal enhances control and visibility over user data.

Source: https://blog.mozilla.org/en/products/advertising/using-trusted-execution-envrionments-for-advertising-use-cases/