Stellar's Protocol 21 upgrade activated on June 18, 2024, introducing five Core Advancement Proposals (CAPs) that enable passkey support for smart contracts, improve state archival, and reduce transaction costs through VM optimization and module caching.
Stellar validators approved Protocol 21, which activates CAP-0051 through CAP-0056. The most significant addition is native secp256r1 verification support (CAP-0051), enabling passkey authentication for smart contract transactions—eliminating the need for seed phrases and secret keys. This leverages WebAuthn standards available on browsers, phones, and hardware tokens. The upgrade also includes four efficiency-focused CAPs: CAP-0053 separates TTL extension for contract instances and code; CAP-0054 refines VM instantiation cost models; CAP-0055 reduces host function linking overhead; and CAP-0056 implements intra-transaction module caching. Together, these changes lower transaction costs, improve network throughput, and enhance scalability. The article highlights community implementations including Soroban by Example, Super Peach, Passkey Kit, and Launchtube.
