1. Basic password security requirement. https://www.tripwire.com/state-of-security/latest-security-news/nearly-half-popular-consumer-websites-lack-basic-password-security-requirements/
2. Keepass. https://keepass.info/
3. The password meter. http://www.passwordmeter.com
4. Phishing activity trends report, second quarter (2016). http://www.antiphishing.org/
5. Poor password requirements of popular consumer websites. https://betanews.com/2017/08/09/consumer-websites-poor-passwords/