link to wikipedia description of cryptographic salt

Doc/library/hashlib.rst

@@ -182,7 +182,7 @@ Key Derivation Function
 Key derivation and key stretching algorithms are designed for secure password
 hashing. Naive algorithms such as ``sha1(password)`` are not resistant against
 brute-force attacks. A good password hashing function must be tunable, slow, and
-include a salt.
+include a `salt <https://en.wikipedia.org/wiki/Salt_%28cryptography%29>`_.
 
 
 .. function:: pbkdf2_hmac(name, password, salt, rounds, dklen=None)