I need a function that will go through and encrypt all the strings

Apparently it's not as simple as I thought. My first instinct was

update yourtable set password = '#hash(password)#'

but that will crash

This is inefficient, but you only have to do it once.

query1
select id, password thepassword
from yourtable

cfloop query="query1"

update yourtable
set password = '#hash(thepassword)#'
where id = #id#

Can you give me the update query that will hash the column please?

For the first question, it depends on the encryption algorithm you want to use. If it was cold fusion hash, a simple update query will do.

For the 2nd question, once again it's simple sql. Hash the test password sting so you are comparing one hashed value to another.