Questions tagged [two-factor]

2-factor-authentification is a hybrid scheme where you know already one half of the password (which keeps constant / static) and then you get the other half by sms or any other means; that 2nd half is a one-time-password.

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4 votes
2 answers
225 views

How can multifactor authentication be used when there needs to be two people with access?

For a business account at a Bitcoin exchange, either of two people need to be able to send bitcoins or withdraw. This account will be configured with two-factor authentication. How can two of the ...
1 vote
0 answers
115 views

Trying to figure out the two-part authentication process. Can anyone give direct instructions?

I'm using btc-e.com verification, in the Finances section. It supplies two key codes and has a square bar code to scan. I've set up my google account for two-part verification, and google is ALSO ...
13 votes
3 answers
4k views

Which Two-factor authentication methods are available at which exchanges?

I see that Mt. Gox now supports the Google Authenticator app (on Android, iOS - iPhone, iPad, iPod Touch, and on Blackberry) for 2-factor authentication (in addition to support for Yubikey, of course)....
6 votes
3 answers
3k views

Which exchanges support U2F authentication? [closed]

I got myself a nice security key (Yubico Fido) today, which utilises the U2F protocol. But to my surprise not a single Bitcoin exchange seems to support this yet, only Google itself. So which ...
0 votes
1 answer
495 views

Disabling GreenAddress 2FA ∵ Google Authenticator doesn't generate the correct OTPs for it

According to the section "I lost my two-factor/mobile/etc (email/OTP|Authenticator/etc), what can I do?" of the GreenAddress FAQ page, You should always have at least two two-factor options enabled....
0 votes
1 answer
348 views

How do I reset my TFA token in Coinbase?

I would like to move my Coinbase Two-factor authentication token from one device to another. I cannot find a location on their website to disable TFA once it has been set up, or to move the token to ...
0 votes
1 answer
77 views

Is my 2FA not working, or do I not understand it?

I have one wallet on Coinbase. They say that I enabled 2FA on it and that if an attacker somehow accessed my account, they would not be able to spend because they would not be able to enter the code ...
0 votes
1 answer
558 views

Are two factor authentication enabled wallets at mtgox or blockchain.info safe even with weak passwords?

Are two factor authentication (2FA) enabled wallets at mtgox/blockchain.info safe even with weak passwords? What are the risks here, except losing one's mobile phone? A Google authenticator is used ...
1 vote
2 answers
12k views

How to use two-factor authentication at btc-e?

btc-e has a very confusing process of enabling 2-factor. How should I use it? Should I generate a one time password with a Yubikey? Should I backup the private key / base32 ? What does this auth ...
2 votes
2 answers
2k views

Is Google Authenticator really useful on blockchain.info?

blockchain.info hosts encrypted wallets, and all decryption is done locally, so having a Google Authenticator bound to a wallet only prevents an attacker from downloading that encrypted wallet. Now, ...
7 votes
3 answers
5k views

Why does Mt Gox disallow YubiKeys purchased direct from Yubikey.com?

I have several Yubikeys and would like to use one or more with MtGox.... however it seems that I can only use keys purchased from Mt Gox on their site. Why did Mt Gox choose to implement security ...
2 votes
0 answers
268 views

Is anyone working on / has implemented a "two-factor paper wallet"?

I just created this wiki page. I'm coining the term here, I think ... not sure what was it called when discussed on Bitcointalk. My question is: Has anyone implemented this "2 factor paper wallet"? ...