Improve wording for salt explanation

Author: mao-sz

nodeJS/authentication/session_based_authentication.md

@@ -341,7 +341,7 @@ The most secure way to store passwords? Don't. Offloading that responsibility to
 
 By far the worst way we can store passwords is to just store them in plaintext like we've done in our example app earlier. Even if we encrypted the passwords, all an attacker would need is the key to decrypt all the passwords. Let's face it, if someone managed to gain access to your database, it probably wouldn't be very hard for them to get the encryption key (assuming they don't already have it).
 
-Remember [hash functions](https://www.theodinproject.com/lessons/javascript-hashmap-data-structure#what-is-a-hash-code) from the Hashmap lesson? We want to hash our passwords, then store the hash since hashes are one-way functions. We also want to [salt](https://en.wikipedia.org/wiki/Salt_(cryptography)) the password when hashing to prevent identical passwords from being stored with identical hashes. On top of all that, we also want the hash function to be purposely slow - not so slow that a normal user will be waiting ages just to log in but certainly slow enough to minimize the number of attempts an attacker might be able to make in a given amount of time.
+Remember [hash functions](https://www.theodinproject.com/lessons/javascript-hashmap-data-structure#what-is-a-hash-code) from the Hashmap lesson? We want to hash our passwords, then store the hash since hashes are one-way functions. We also want to [salt](https://en.wikipedia.org/wiki/Salt_(cryptography)) the password when hashing so that the identical passwords will produce a different hash each time, preventing attackers from comparing hashes against precomputed hashes of common passwords (often referred to as "rainbow tables"). On top of all that, we also want the hash function to be purposely slow - not so slow that a normal user will be waiting ages just to log in but certainly slow enough to minimize the number of attempts an attacker might be able to make in a given amount of time.
 
 #### Argon2