safecounting.com

What It Is

PSC (Private Set-Union Cardinality) is a cryptographic protocol and proof-of-concept implementation developed collaboratively by researchers from Georgetown University, Tulane University, and the U.S. Naval Research Laboratory. It addresses a clearly defined problem: counting the total number of unique items across multiple data collectors without revealing any information beyond the final count. A typical use case is an anonymity network such as Tor wanting to know how many unique users have used a distributed service.

Core Capabilities

In terms of functionality and use cases, PSC is aimed at privacy-preserving distributed measurement, with a focus on private set-union cardinality computation rather than serving as a general-purpose data analytics platform. The text emphasizes that its correctness and security are proven under the Universally Composable framework, and that it can withstand a model where nearly all aggregators are compromised by an active attacker. It also considers the risk of adaptive corruption among data collectors. To reduce privacy leakage from measurement outputs, the project also demonstrates how to make the output satisfy differential privacy.

Open Source, Deployment, and Ecosystem

The project provides PSC source code, but the text does not specify its license, programming language, framework dependencies, API, or SDK. Since an implementation is available, researchers and engineering teams should be able to install and run it themselves, but the project also notes that PSC is still in active development and may contain bugs. On the documentation side, the project explicitly states that documentation is still being actively improved, and that installation and usage questions should be directed to the researchers. This suggests a relatively high barrier to entry and makes it unsuitable for teams expecting an out-of-the-box solution. In terms of ecosystem, the text only mentions that the paper was published at ACM CCS 2017; there is no information about plugins, cloud services, or third-party integrations.

Pricing and Access from China

The text does not mention commercial pricing, paid plans, or payment methods, so PSC can be considered a research-oriented source-code project rather than a commercial SaaS product. Access from China cannot be determined from the text alone and should be marked as unknown. If it depends on overseas code hosting or academic paper resources, actual accessibility may be affected by local network conditions. Alternative directions include open-source libraries related to secure multi-party computation, private set intersection/union cardinality, and differential privacy statistics, such as OpenMined, Microsoft SEAL, or projects similar to Google Private Join and Compute.

Pros, Cons, and Who It’s For

PSC’s strengths are its clear research objective, solid security proofs, and focus on highly sensitive real-world scenarios such as anonymity networks. It also claims low computational overhead and reasonable bandwidth requirements at practical deployment scales. Its weaknesses are the lack of engineering-oriented information, including mature documentation, release notes, language stack details, APIs, and commercial support. PSC is best suited for researchers in cryptography, security measurement, anonymity networks, and privacy-preserving computation, or for engineering teams capable of reading the paper and adapting the source code. It is not suitable for ordinary business teams looking to deploy a production statistics system directly.