A website stores username and password in a session cookie. In the cookie the
password is "encrypted" or modified in some way. Given that the "encrypted"
version is always the same, I do not believe there is a time sensitive factor.
I could create multiple sets of this data, but it's time consuming.
Knowing this how difficult would it be, and what methods
would be used, to determine what the calculation used is?
To phrase it differently, could one determine how to create a new pair for given plain text?
What does it change if I can determine the hexMD5 value of a known concatenation
of this value and two more. This would be such that I the password, a username,
the "encrypted" password, and a hexMD5 of the username + "encrypted" password
+ a known constant "secret" string. Which makes me think the method is symmetric.