step-ca vs XiPKI

step-ca is an online Certificate Authority for automating X.509 and SSH certificate management. It issues X.509 certificates for TLS, mutual TLS, document signing and authentication, as well as SSH certificates for users and hosts. Provisioners can authorize issuance through ACME challenges, OIDC tokens, cloud instance identity documents and short-lived JWK tokens. Automated issuance and renewal are supported for clients, servers and Kubernetes workloads, alongside passive revocation. Templates can customize SANs or OIDs, restrict domains or key sizes, and create longer certificate chains. For CA signing-key protection, step-ca integrates with Google Cloud KMS, AWS KMS, Azure Key Vault, PKCS#11 HSMs, TPM 2.0 and YubiKey PIV. Its intended PKI design uses an offline root CA and a configured intermediate CA that issues end-entity certificates. Installation options include macOS, Windows, Linux, Kubernetes and Docker, and database choices include Badger, BoltDB, MySQL and PostgreSQL. The open-source plan costs nothing. Community help is available through Discord, with dedicated support contracts from Smallstep.

XiPKI is an open-source public key infrastructure system for certification authority, registration authority, and OCSP responder functions, aimed at critical infrastructure. It supports multiple CAs in one instance, database clusters, and active instances for the same CA, with management through embedded OSGi commands and an API. Its CA gateway supports EST, SCEP, CMP, ACME, and its RESTful API. The OCSP responder handles RFC 2560, RFC 6960, and RFC 5019, along with signed and unsigned requests, health checks, and multiple certificate status sources. HSM connections use PKCS#11; listed devices include AWS CloudHSM, Nitrokey, nCipher, Sansec, SoftHSM, TASS, Thales, and Utimaco. The project describes native support for ML-DSA, ML-KEM, and composite post-quantum algorithms. XiPKI is free under Apache License 2.0. It supports Linux and macOS and requires Java 11 or later and Tomcat 10 or 11. Listed databases include DB2, MariaDB, MySQL, Oracle, PostgreSQL, H2, and HSQLDB.