Are there any downsides?
One-time passwords do a great job to help avoid many of the common issues with real passwords such as:
- Weak passwords
- Reusing passwords across multiple sites
- Writing passwords down
- No warning when someone else has access to your password/account
There is some room for vulnerability in the current system.
Encryption – Emailing a link that can provide unlimited account access, should of course be done in an encrypted fashion. However, this isn’t always possible and transmitting it in plain-text over email or SMS could be a major security vulnerability.
Degrades security – A potential downfall for one-time passwords, especially with Mediums implementation, is that any one-time password account is only as secure as your authentication email account.
For example, it would be useless to manage every one of your online accounts with a one-time password, but only secure your email with a weak password (as many people do). Remember, your email password should be the strongest of all your passwords as it can hold the key to the rest of them. One-time passwords make this even more pertinent.
Forwarding – Obviously it is unlikely, but with the current implementations, anyone with the link would be able to access the account. If you forwarded an email by mistake or pasted the link in the wrong place, then this could leave you vulnerable.
Some verification that the link is being clicked within the correct email account would be an added bonus so that the link would be a big bonus.
Alternatives
So while it is up to you whether or not you want to secure your online accounts with one-time passwords, if you are looking to improve the security of your online accounts I can recommend deploying Two-Factor Authentication.
Two-Factor Authentication is perhaps the simplest way to prevent unauthorised access to your online accounts and is very low risk. For more information on Two-Factor Authentication, check out the video below: