Live data from Hacker News

How to Set Up Two-Factor Authentication for Login and Sudo

linux.com

1–10 of 41 posts

Re: How to Set Up Two-Factor Authentication for Login and Sudo

#4
post #2

Wouldn't this add a hard dependency to an internet connection? This sounds like a major drawback in the event of an outage, and would take away a major feature of most computers.

The solution is based on Google Authenticator, which is based on TOTP:

https://en.wikipedia.org/wiki/Time-based_One-time_Password_A...

The only requirements of TOTP are an accurate time source and keying data for an HMAC. No internet connectivity explicitly required.

Re: How to Set Up Two-Factor Authentication for Login and Sudo

#5
post #4
post #2

Wouldn't this add a hard dependency to an internet connection? This sounds like a major drawback in the event of an outage, and would take away a major feature of most computers.

The solution is based on Google Authenticator, which is based on TOTP: https://en.wikipedia.org/wiki/Time-based_One-time_Password_A... The only requirements of TOTP are an accurate time source and keying data for an HMAC. No internet connectivity explicitly required.

Until you need sudo access to fix ntp

Re: How to Set Up Two-Factor Authentication for Login and Sudo

#6
post #5
post #4

Earlier quoted context omitted.

The solution is based on Google Authenticator, which is based on TOTP: https://en.wikipedia.org/wiki/Time-based_One-time_Password_A... The only requirements of TOTP are an accurate time source and keying data for an HMAC. No internet connectivity explicitly required.

Until you need sudo access to fix ntp

You could change the phone's time settings to match the computer's. TOTP doesn't require precise sync anyway, it usually works as long as the two clocks are within 30s of each other.

Re: How to Set Up Two-Factor Authentication for Login and Sudo

#8
post #5

Earlier quoted context omitted.

Until you need sudo access to fix ntp

You could change the phone's time settings to match the computer's. TOTP doesn't require precise sync anyway, it usually works as long as the two clocks are within 30s of each other.

If your virtual machine can't sync with an NTP time server for an extended period of time (outbound security group), it will drift beyond 30s from actual time (just saw this in AWS about a year go).
Post reply on HN