Google Open-Sources Cryptographic Protocol

Google this week rolled out a new type of multi-party computation (MPC) to help organizations better collaborate with confidential data sets. 

Meant to augment the cryptographic protocol known as private set intersection (PSI), the new MPC is called Private Join and Compute and has been released as open source. 

The tool allows organizations to gain aggregated insights about each other’s data without any of them learning any information about individuals in the datasets. 

With this cryptographic protocol, organizations can encrypt identifiers and associated data, and then join them so they can do certain types of calculations on the overlapping set of data and draw useful information from both datasets in aggregate. 

“All inputs (identifiers and their associated data) remain fully encrypted and unreadable throughout the process. Neither party ever reveals their raw data, but they can still answer the questions at hand using the output of the computation. This end result is the only thing that’s decrypted and shared in the form of aggregated statistics,” Google explains. 

Private Join and Compute combines two fundamental cryptographic techniques, namely PSI, which allows two parties to privately join sets and discover common identifiers, and homomorphic encryption, which makes it possible to perform certain types of computation directly on encrypted data without having to decrypt it first.

Thus, only the size of the joined set and the statistics of its associated values are revealed. Individual items are encrypted using random keys and are not available in raw form to the other party or anyone else, Google says. 

The company says it is committed to applying MPC and encryption technologies to more concrete, real-world issues through making privacy technology more widely available. The technology is expected to help advance research in fields that require organizations to work together, including public policy, diversity and inclusion, healthcare, and car safety standards. 

“Private Join and Compute keeps individual information safe while allowing organizations to accurately compute and draw useful insights from aggregate statistics. By sharing the technology more widely, we hope this expands the use cases for secure computing,” Google says. 

Related: Google Introduces Open Source Cross-Platform Crypto Library

Related: Fitting Forward Secrecy Into Today’s Security Architecture