ssf2/ssf_md_alg is a SAP Parameter attribute which is used to control Message Digest Algorithm for 2nd SSF toolkit information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
Name of message digest algorithm (that is, the hash procedure) that is
used as the standard value for the security product specified with
ssf2/ssfapi_lib.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.