Passwords are used for everything now, so they need to be safe. Here is the basis behind password theory:
Each plaintext Character entered increases the permutations by a factor of the plaintext possibilities.
For example, pin numbers, which use only 0-9:
a three digit password would have 10x10x10= 1000 permutations
a four digit would have 10x10x10x10= 10,000 permutations
so the more digits, the hard the password is to crack via brute force (checking all the possibilities systematically)
Normally, modern passwords are case sensitive and allow a variety of characters, Case sensitivity allows for much more permutations, and should be used.
take this example password:
chicken
7 letters with 26 possibilities= 26^7
versus a strong password of the same vein:
Ch1cken
7 letters still, but with a Capital letter and number to increase possibilities:
0-9 =10 possibilities + lower case alphabet (26) + uppercase alphabet (26)= 26+26+10 =62 possibilities
OR 62^7 possibilities
62^7 vs 27^7
the "Ch1cken" password would take 438.45839 times longer to brute force crack than "chicken" would.
Linux systems and many modern websites allow special charaters too. {{%$#@!^&*(), etc.
this can increase the permutions greatly, moving the base options for characters to 112. If you can use a password with extra charaters, it is the most safe.
