Send password over TCP connection

[Peter Hansen]

dcrespo wrote:
> then, what you proppose?

I'll assume that question was for me, in response to my comment that one 
should never store passwords in the clear.

Do you know how any other system manages to do this?  Linux, for example 
(assuming a properly configured system)?  The passwords aren't stored: 
hashes of the passwords are stored (with additional things thrown in to 
prevent certain kinds of attacks even if someone nabs the password 
(/etc/shadow) file).  If you store the password or even encrypt it (i.e. 
something that can be reversed if someone knows the key), it's a risk.

If you don't know about this stuff yet, I strongly suggest lots of 
additional research and reading prior to implementing a serious system. 
  There are _many_ web pages to be found which discuss this sort of 
thing, probably including lots of tutorials for people starting on the 
ground floor.

I bet Paul R or others more experienced in this area can point us to 
some excellent ones, but a little googling with "passwords store clear 
text" or "encrypted passwords" would get you started.  I expect that 
would quickly lead to the term "hashing", since you really don't want to 
just encrypt the password: that can easily be reversed if anyone has the 
key, and certainly an administrator could access the key used by some 
random application that encrypts its passwords.  The first few hits for 
that last search seem to include pages that introduce the concept of 
"salt", one of the "additional things" I mentioned above.

I'm not going to try to give a tutorial: I'm not nearly expert enough to 
be trusted for that. :-)  I just wanted to warn against one of the most 
basic and easily avoidable problems.

-Peter