Compact credentials
From GridSiteWiki
Compact Credentials are a way of representing GridSite's internal GRSTcred structures as strings. They are used in the GRST_CRED_n environment variables exported by mod_gridsite to CGI, SHMTL, PHP etc.
It always starts with the type of credential (X.509, GSI PROXY, VOMS Attribute), the next two numbers are the times that the credential are valid between (as seconds since 00:00:00 1970-01-01 UTC), the 4th value is the level of delegation (for that particular credential) and the final value is the DN or the VOMS FQAN.