login/disable_password_logon is a SAP Parameter attribute which is used to control login/disable_password_logon 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 .
There are several types of user authentication:
Using password (conventional logon)
Using an external security product (SNC)
Using an X.509 browser certificate (intranet/Internet)
Using a Workplace Single Sign-On (SSO) ticket
The default logon method is password user authentication. When using
other types of authentication methods (see above), you may want to
deactivate the password-based logon option
(login/disable_password_logon).
Caution
Only deactivate password-based logon, when you are sure that all users
can log on using another method (using SNC, X.509, or SSO ticket).
See SAP Parameter Documentation for full SAP documentation for this profile parameter.