---
title: "passwords"
aliases: 
tags: 
- comp210
---

# Passwords
- not good
- lots of bad advice
- we are lazy
- "safe" passwords are difficult to enter on touch screen devices
- to many accouts

## entropy
- amount of randomness
- measure of the number of guesse an attacker would need to brute foarce
- $E = log_2(A^L)$ 
- A = size of alphabet
- L = length of password
- E = entropy in bits
- 80 bits is "safe"
	- would take decades
- 6 digits passoword - 29 bits (took 4 seconds to brute force)
- + uppercase and numbers - 36 bits