Tink is a multi-language, cross-platform, open source library that provides cryptographic APIs that are secure, easy to use correctly, and hard(er) to misuse.

A configuration as code language with rich validation and tooling.

Java client for ACME (Let's Encrypt)

XiPKI: Compact open source PKI (CA, OCSP responder, certificate protocols ACME, CMP, EST, SCEP).

The Dogtag Certificate System is an enterprise-class Certificate Authority (CA) which supports all aspects of certificate lifecycle management, including key archival, OCSP and smartcard management.