Starting with Security in SAP, you may consider the following list of main SAP Security Transaction Codes including Security management in SAP for People and Process.
SAP Audit tcodes regroups the main/ important SAP Transactions code for SAP ERP Management Audit.
SAP CRM Authorizations: this is a PDF Guide for SAP CRM Authorization management. It helps understanding the keys points for Authorization within SAP Customer Relationship Management.
Certificate X509 specifies, amongst other things, standard formats for public key certificates, certificate revocation lists, attribute certificates, and a certification path validation algorithm.In cryptography, X.509 is an ITU-T standard for a public key infrastructure (PKI) and Privilege Management Infrastructure (PMI). *