The Internet Security Research Group (ISRG) announced several key updates in May 2026, including the optional availability of 45-day Let's Encrypt certificates and significant performance achievements for Rustls. These changes are part of an industry-wide shift towards shorter certificate lifetimes, with a full transition planned for 2028.
Since May 13, users can opt for 45-day certificates via the tlsserver profile, allowing for testing and early adoption of the upcoming standard. ISRG also highlighted that these shorter certificate durations will not impact existing rate limits for subscribers.
In other news, Prossimo's Rustls, a memory-safe TLS library, demonstrated superior performance in Q1 2026 benchmarks, outperforming OpenSSL and BoringSSL in 14 out of 16 tests. The team is also developing a "split mode" feature for the upcoming Rustls 0.24 release, which aims to nearly double throughput for single connections by enabling simultaneous sending and receiving.
ISRG welcomed Porkbun as a new Silver Sponsor, with Andrew Merriam, COO of Porkbun.com, saying, "Porkbun pioneered free Let's Encrypt SSL on every domain. That customer-first approach made us the top-recommended registrar and an ISRG sponsor." Additionally, ISRG board member Jennifer Granick was recognized by Dark Reading for her contributions to cybersecurity and Internet privacy law. ISRG engineers Tim Geoghegan and J.C. Jones are scheduled to present on Divvi Up, their privacy-preserving telemetry system, at USENIX PEPR on June 2.