Authlogic question on update of very old site

I have an internally used rails 2.3.8 system that I have updated to rails 5.2. The test database works fine, but when I bring the legacy data over, none of the passwords work for the existing users. I can see that in my test database and legacy database, the same user name with the same password entered results in a different encrypted password.

I see there is a secret_key_base value in 5.2. Is that what Authlogic uses to convert the entered password to compare with the crypted password? If so, any idea where I find the same thing in 2.3.8?