Google Online Security Blog: OpenTitan at One Year: the Open Source Journey to Secure Silicon

Security Blog

The latest news and insights from Google on security and safety on the Internet

OpenTitan at One Year: the Open Source Journey to Secure Silicon

December 7, 2020

Posted by Dominic Rizzo, OpenTitan Lead, Google
OpenTitan
OpenTitan by the Numbers
OpenTitan has doubled many metrics in the year since our public launch: in design size, verification testing, software test suites, documentation, and unique collaborators at least. Crucially, this growth has been both in the design verification collateral required for high volume production-quality silicon, as well as the digital design itself, a first for any open source silicon project.

More than doubled the number of commits at launch: from 2,500 to over 6,100 (across OpenTitan and the Ibex RISC-V core sub-project).

Grew to over 141K lines of code (LOC) of System Verilog digital design and verification.

Added 13 new IP blocks to grow to a total to 29 distinct hardware units.

Implemented 14 Device Interface Functions (DIFs) for a total 15 KLOC of C11 source code and 8 KLOC of test software.

Increased our design verification suite to over 66,000 lines of test code for all IP blocks.

Expanded documentation to over 35,000 lines of Markdown.

Accepted contributions from 52 new unique contributors, bringing our total to 100.

Increased community presence as shown by an aggregate of over 1,200 Github stars between OpenTitan and Ibex.

One year of OpenTitan and Ibex growth on GitHub: the total number of commits grew from 2,500 to over 6,100.

OpenTitan’s core principlesstyle guidesauto-generated documentationdesign verificationstages

One year of growth in Design Verification: from 30,000 to over 65,000 lines of testing source code. Each color represents design verification for an individual IP block.

Innovating for Open Silicon Development
Besides writing code, we have made significant advances in developing processes and security framework for high quality, secure open source silicon development. Design success is not just measured by the hardware, highly functional software and a firm contract between the two, with well-defined interfaces and well-understood behavior, play an important role.
OpenTitan’s hardware-software contract is realized by our DIF methodology, yet another way in which we ensure hardware IP quality. DIFs are a form of hardware-software co-design and the basis of our chip-level design verification testing infrastructure. Each OpenTitan IP block requires a style guide-compliant DIF, and this year we implemented 14 DIFs for a total 15 KLOC of C11 source code and 8 KLOC of tests.
We also reached a major milestone by publishing an open Security Model for a silicon root of trust, an industry first. This comprehensive guidance demonstrates how OpenTitan provides the core security properties required of a secure root of trust. It covers provisioning, secure boot, device identity, and attestation, and our ownership transfer mechanism, among other topics.
Expanding the OpenTitan Ecosystem
Besides engineering effort and methodology development, the OpenTitan coalition added two new Steering Committee members in support of lowRISC as an open source not-for-profit organization. Seagate, a leader in storage technology, and Giesecke and Devrient Mobile Security, a major producer of certified secure systems. We also chartered our Technical Committee to steer technical development of the project. Technical Committee members are drawn from across our organizational and individual contributors, approving 9 technical RFCs and adding 11 new project committers this past year.
On the strength of the OpenTitan open source project’s engineering progress, we are excited to announce today that Nuvoton and Google are collaborating on the first discrete OpenTitan silicon product. Much like the Linux kernel is itself not a complete operating system, OpenTitan’s open source design must be instantiated in a larger, complete piece of silicon. We look forward to sharing more on the industry’s first open source root of trust silicon tapeout in the coming months.
Onward to 2021
OpenTitan’s future is bright, and as a project it fully demonstrates the potential for open source design to enable collaboration across disparate, geographically far flung teams and organizations, to enhance security through transparency, and enable innovation in the open. We could not do this without our committed project partners and supporters, to whom we owe all this progress: Giesecke and Devrient Mobile Security, Western Digital, Seagate, the lowRISC CIC, Nuvoton, ETH Zürich, and many independent contributors.
Interested in contributing to the industry's first open source silicon root of trust? Contact us here.