The CILogon Certification Authorities provide X.509 certificates for access to cyberinfrastructure. Each CILogon CA operates at a defined level of assurance.
Self-signed certificates and other configuration files for the CILogon CAs are available from the International Grid Trust Federation CA Distribution and from CILogon GitHub.
CILogon is beginning to retire our X.509 certificate services. See CILogon X.509 Certificate Retirement Plan for details.