Why is a password with both numbers and letters stronger than one with only letters? Attackers will include numbers in their brute force attempts anyway, so how does it make a difference?

Question

Why is a password with both numbers and letters stronger than one with only letters? Attackers will include numbers in their brute force attempts anyway, so how does it make a difference?

In: Technology

Answer 1

Simply put, using numbers and letters increase the amount of characters that need to be included when attempting to guess a password.

With 12 characters,
if using numbers only: 10 characters (14 hours to crack)
if using lower case letters only: 26 characters
if using upper case and lower case letters: 52 characters
If using numbers, upper case, lower case, and special characters: 83 characters (205 million years)

Making your password 13 characters long would increase the crack time to 20 billion years.

Thus, if you have a 13 character password where someone has to try 83 different character variations for each bit in your password you dramatically increase the amount of time required to crack a password.