ICSF is the interface to hardware cryptographic devices. SSH Tectia Server for IBM z/OS benefits from the higher security and performance that these devices provide for keys and certificates managed by SAF.
SSH Tectia Server for IBM z/OS also supports SAF keys that do not use hardware crypto devices, the so-called NON-ICSF keys. For these keys, the cryptographic operations are performed in software.
The interface to SAF in SSH Tectia Server for IBM z/OS 5.3 is implemented with an SSH Tectia External Key Provider. The External Key Providers are configured with specification strings in a configuration file or on a command line.
SSH Tectia Server for IBM z/OS validates public keys by matching them against trusted keys stored in the file system.
SAF does a limited form of certificate checking that only determines which SAF user is the owner of the certificate. SAF does not check the contents of the certificate, such as the validity period, or check for certificate revocation. Instead of revoking a certificate the site can reduce the user's access rights in SAF.
A trusted key provider must be configured if SAF certificate checking is to be used.
To enable SAF checking of remote Secure Shell servers, their certificates can be entered into SAF as SITE keys and placed on a key ring for the trusted key provider.