About password_to_key algorithm.

Hi all,

I came across a document/RFC long ago, that if the password is given 
repeatedly, then the key generated from it is the same.
For example, the key generated for the passwords "test", "testtest", 
"testtesttest" are all the same.

Can anyone of you, please point me to that concreate evidence.

Thanks for your time and effort.

Regards,
R.Parasuraman.