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0 pointstheamk6y ago0 comments

I disagree, I believe TOTP belongs firmly in the "something you have" category. You cannot memorize TOTP password, nor you can store in your password manager. You also cannot pass that knowledge to another person. So this is more like a public key than a password.

Ultimately, everything is "permanent, unchangeable secret", including private key and biometric data. Where the data is stored and how is it accessed makes all the difference.

I could not find the original definition of "something you have", but modern standards like PCI actually give OTP auth as an example of "something you have" (p. 4 of [1])

(I am not looking at the degenerate case of running TOTP app on the same device / same security domain -- it does not describe most cases, and there are some fairly straightforward technical measures to defeat this)

[1] https://www.pcisecuritystandards.org/pdfs/Multi-Factor-Authe...

0 comments

thaumasiotes6y ago

> You cannot memorize TOTP password, nor you can store in your password manager. You also cannot pass that knowledge to another person.

But none of these things are true. For example, my most recent job involved sharing a 2FA-protected online account. We all had the code.

theamkOP6y ago

Sorry, "none of these things are true" in your environment. They are certainly true for other people, in fact, I bet they are true for majority of them.

I think analogy to physical house keys is very helpful. What did your work do?

Did you show the enrollment QR code, and multiple people scanned it --> this is like duplicating house key.

Did you put the key into password manager -> this is like that combination lockbox that releases house key if you enter the right combination.

People do all sorts of unusual things, this does not change the properties of intended usage.

thaumasiotes6y ago

> They are certainly true for other people, in fact, I bet they are true for majority of them.

Well, no. Everyone who uses TOTP, without exception, has their secret stored in a password manager. That's what the TOTP app or device is.

1 more reply

michaelmior6y ago

> nor you can store in your password manager

Some 2FA apps also allow you to back up your codes to a cloud service.

theamkOP6y ago

Yes, but I put it into category of "unsafe things that defeat the point of mechanism"

For example, you can put your spare house key under doormat. This effectively makes a lock on your house door require "something you know" (you need to know where the key is stored).

However, that does not mean that we can say that all keys are "something you know". The fact that many people decided to compromise their security does not reflect on other intended use of locks and keys.

michaelmior6y ago

Agreed. But I think it goes to show how blurry the line is between "know" and "have."

j / k navigate · click thread line to collapse

0 pointstheamk6y ago0 comments

Ultimately, everything is "permanent, unchangeable secret", including private key and biometric data. Where the data is stored and how is it accessed makes all the difference.

I could not find the original definition of "something you have", but modern standards like PCI actually give OTP auth as an example of "something you have" (p. 4 of [1])

[1] https://www.pcisecuritystandards.org/pdfs/Multi-Factor-Authe...

0 comments

thaumasiotes6y ago

> You cannot memorize TOTP password, nor you can store in your password manager. You also cannot pass that knowledge to another person.

But none of these things are true. For example, my most recent job involved sharing a 2FA-protected online account. We all had the code.

theamkOP6y ago

Sorry, "none of these things are true" in your environment. They are certainly true for other people, in fact, I bet they are true for majority of them.

I think analogy to physical house keys is very helpful. What did your work do?

Did you show the enrollment QR code, and multiple people scanned it --> this is like duplicating house key.

Did you put the key into password manager -> this is like that combination lockbox that releases house key if you enter the right combination.

People do all sorts of unusual things, this does not change the properties of intended usage.

thaumasiotes6y ago

> They are certainly true for other people, in fact, I bet they are true for majority of them.

Well, no. Everyone who uses TOTP, without exception, has their secret stored in a password manager. That's what the TOTP app or device is.

1 more reply

michaelmior6y ago

> nor you can store in your password manager

Some 2FA apps also allow you to back up your codes to a cloud service.

theamkOP6y ago

Yes, but I put it into category of "unsafe things that defeat the point of mechanism"

For example, you can put your spare house key under doormat. This effectively makes a lock on your house door require "something you know" (you need to know where the key is stored).

michaelmior6y ago

Agreed. But I think it goes to show how blurry the line is between "know" and "have."

j / k navigate · click thread line to collapse