Homomorphic Encryption vs. Confidential Computing: A Comparison of Two Privacy Enhancing Technologies

Confidential Computing and Homomorphic Encryption are both data privacy and security technologies designed to safeguard data privacy and security in various computing environments. They prevent unauthorized access to sensitive information when it’s actively being utilized, which addresses a critical security gap in data processing. While they share some common goals, Confidential Computing and Homomorphic Encryption have significantly different approaches to safeguard data privacy and security.  

Definitions

Confidential Computing aims to prevent unauthorized access to sensitive data during computation. It is an infrastructure technology that establishes a security boundary, or secure enclave called a trusted execution environment (TEE), to protect both data and code from malicious access and tampering with minimal impact on performance. It ensures that data remains encrypted and protected even when it is being processed by applications, operating systems, or cloud service providers.

Homomorphic Encryption is a specific cryptographic technique that allows computations to be performed on encrypted data without decrypting it first. The output of the computation is also in encrypted form and can only be decrypted by the authorized party, maintaining data privacy throughout the computation.

The differences between Confidential Computing and Homomorphic Encryption are in their implementations and performance. The following sections compare data handling and security, performance, and multi-party analytics.

Data Handling and Security

In Confidential Computing, data is decrypted only within a TEE that isolates and protects the computation from the rest of the system. The TEE provides strong isolation and memory protection, making it challenging for attackers to access sensitive data during processing. Once the computation is complete, the data is re-encrypted and returned to its original encrypted state.

Homomorphic Encryption allows computations to be performed directly on encrypted data without exposing the plaintext to the computing environment, which enables users to process sensitive data without revealing its contents to the processing entity.

Homomorphic Encryption relies on the mathematical properties of encryption algorithms to allow computations on encrypted data without decrypting it. Data security is based on the hardness of certain mathematical problems and breaking it would require significant computational resources.

Performance

Confidential Computing typically involves hardware-based solutions such as Intel SGX (Software Guard Extensions) or AMD SEV (Secure Encrypted Virtualization). While these hardware solutions offer strong security, establishing secure enclaves might introduce some performance overhead. Confidential Computing is suitable for complex workloads and large datasets and often requires collaboration with a cloud provider or an enterprise partner.

Homomorphic Encryption is an open-source solution with flexibility in deployment. While it is computationally intensive, performing operations on encrypted data can be significantly slower than traditional unencrypted computations. Homomorphic encryption is best suited for simple computations on small to moderately sized datasets. However, advancements in techniques and hardware acceleration are gradually improving its performance.

Multi-Party Analytics

Multi-Party Analytics involves data owners allowing their data to be analyzed by other parties without sharing the actual data itself. The choice between confidential computing and homomorphic encryption for multi-party analytics depends on the level of trust among parties involved in data processing.

While Confidential Computing is suitable for complex workloads and large datasets, it requires mutually trusting parties because of centralized compute nodes. Parties must trust the application code, establish data use agreements, and agree on code review and validation policies.

With homomorphic encryption, parties can be mutually distrustful because of encrypted data while performing analytics, therefore, it is the preferred choice for multi-party analytics when viability is assured. However, its performance limitations make it unsuitable for large datasets and complex computations.

Use Cases

Confidential Computing is suitable for scenarios where sensitive data needs to be processed on untrusted or third-party systems, such as in cloud computing environments or shared data centers. It’s beneficial for industries where privacy and data protection are critical, such as finance and healthcare.

Homomorphic Encryption is valuable when data owners want to delegate computations on their sensitive data to external parties (e.g., data processors or machine learning service providers) without revealing the data’s content. It’s particularly useful in privacy-sensitive applications like secure outsourced data processing and privacy-preserving machine learning.

Confidential Computing and Homomorphic Encryption represent two distinct approaches to protecting data while it’s in use. Each has its unique advantages and limitations, and the choice between them depends on the specific use case and security requirements. However, they are not standalone solutions, but tools to be incorporated into broader enterprise security strategies. As technology evolves, both approaches are likely to continue improving and expanding their capabilities in the realm of data security and privacy.