One-time password (OTP) protocols and implementations (software and hardware)

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3
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0answers
75 views

Generate secure one-time codes containing information

I need to create a system that allows a user to enter codes to charge an allowance. Embedded in this code should be the amount to charge the allowance. The user would pay for a code which would then ...
0
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0answers
23 views

Password vault - Technical Details [closed]

I have some questions about password vault (ex: Cyber Ark) implementations, with focus on Central Password Manager. How is the password vault protected ? Is encryption part of the scheme, or simply ...
12
votes
1answer
601 views

Why is the truncate function for HMAC one time passwords so complicated?

I've been reading through RFC4226 as part of some research and I was wondering why the function to truncate the HMAC was so complicated. As far as I understand it, the last 4 bits of the HMAC define ...
2
votes
2answers
68 views

One Time Password via Text Message: Possible exploits?

Is there a credible scenario in which the OTP (One Time Password) for online credit card transactions ( specifically for Verified by Visa) can be bypassed? Context: A guy I know was cheated via the ...
1
vote
1answer
91 views

OTP for syncing mobile device

Scenario: a web app with two-factor authentication using username/password and hardware OTP. Once logged into the app, one of the app modules should be used in a tablet or any mobile device without a ...
66
votes
3answers
21k views

How does Google Authenticator work?

Google Authenticator is an alternative to SMS for 2Step verification, installing an app on Android where the codes will be sent. It works without any connectivity; it even works on plane mode. This ...
1
vote
0answers
55 views

Store 2-legged one-time password's key securely

I have a system with a OTP authentication and I need a method to encrypt the main "secret algorithm". In my system each OTP has a pair named "solution" and it is also changing like the OTP. I need to ...
0
votes
1answer
88 views

find out the algorithm based on some examples?

I have an OTP generator that receive two numbers less than 99 as input and return an 8 digit number as its output. I know it has a simple algorithm. because its processor is just an ATMEGA8 micro ...
1
vote
1answer
35 views

Implement GPG Verification (Bitcoin-OTC)

I'm looking to implement a "Verify with Bitcoin-OTC" feature for my web app. The general idea is the user would prove he owns a particular account on the external site Bitcoin-OTC and my app would ...
1
vote
1answer
75 views

Secure copy-paste from phone to computer

Some computers on my university block the keepass application which I use as a password manager. I'm thinking of building a small web application + Android app which lets me securely copy a string ...
1
vote
0answers
85 views

How secure is a password app that stores both the password and two factor secret in one place?

Take for example 1Password, that now can store your password and one time password secret in a single place (your 1Password vault). I know it isn't truly two-factor anymore, but how much better is it ...
0
votes
1answer
21 views

When, during authentication, should I ask for an OTP token?

I was working on implementing an OTP strategy in our login process of a web application when I was asking myself: Should I ask for the OTP token before or after asking for the username/password? What ...
0
votes
2answers
37 views

Usability of a found OTP Token for my own system [closed]

I found a one-time-password token and am unable to find out who it belongs to or where it has been used. It seems to be manufactured by a company called "ActivIdentity" (now "HID") and called the ...
0
votes
3answers
57 views

How to integrate AAA and otp

We have AAA services enabled in our organization (about 1000 clients). We want also to add otp (one time password) service. What are the main security concerns about integrating them. Is there any ...
-1
votes
1answer
26 views

Double step verification system for homepage

I want to share some of my work with some double step verification system. PGP is not enough, since some of my clients cannot use it. First, you need a password to login but you also need the code ...
2
votes
1answer
100 views

Should LastPass use the YubiKey public identifier as a secret key?

I've just picked up a YubiKey. However, the demo Yubico redirect you to is served over plain HTTP, over which each OTP you generate during the demo is POSTed, enabling you to verify that your key is ...
0
votes
2answers
173 views

Where is the TOTP secret key stored on client applications?

I'm new to concept of TOTP, but as I understand, 16-character base32-encoded shared secret is stored in the client application(for example Authy, FreeOTP)? This means that if I remove the application, ...
0
votes
0answers
24 views

Negotiate n-bits key with Diffie-Hellman protocol (or other key exchange protocol)

I've got ASCII message. I convert it to binary - then I've got 8*(ASCII message length) bits - let us assume this value will be called n. I have to negotiate key, which length (after conversion to ...
1
vote
1answer
83 views

Best practices for usefully storing two factor authentication backup codes?

For a lot of web services offering two factor authentication, after setting up the system, you are given a short list of backup codes (one-time pads) that are around 7-10 characters long. These are ...
0
votes
1answer
46 views

Algorithms for transaction authentication

It's unclear to me how transaction signing and transaction authentication work. Industrial solutions use both symmetric and asymmetric algorithms to compute the signature. What does RSA add the ...
2
votes
0answers
48 views

HMAC-SHA256 Transaction signing [closed]

Can rfc6238 be used for transaction signing by concatenating the random seed string with transaction details (such as amount and target account number) ? Could a transaction authorization 8-cipher OTP ...
1
vote
1answer
120 views

Algorithm to Transaction Data Signing

Transaction Data Signing I need an idea to develop a very secure algorithm to authenticate online operations using PHP in the server and an Android app in the user's device. What is the idea? The ...
6
votes
1answer
153 views

Google Authenticator Error on Reboot

I have set up an SSH server to accept only login using codes generated by Google Authenticator (I have disabled all other forms of authentication on that port). After having rebooted my remote ...
5
votes
3answers
4k views

Does adding two-factor authentication by OTP really make KeePass more secure

KeePass is an application that keeps all your passwords for you in a database. It is primarily protected by a master password and/or keyfile. If the database is properly encrypted with that password ...
0
votes
1answer
244 views

KeePass OTP plugin circumvents inbuilt protections?

I have read the question on HOTP implementation in KeePass HERE. This question is however on the other newer plugin KeeChallenge. According to the documentation, the a secret is encrypted and can ...
5
votes
1answer
759 views

What are the differences between the U2F and UAF FIDO authentication standards?

Google recently announced support for Universal 2nd Factor (U2F) authentication in Chrome and started allowing that authentication mechanism to be used for 2-factor authentication across their various ...
34
votes
4answers
8k views

How secure are the FIDO U2F tokens

Google and Yubico just announced the availability of cryptographic security tokens following the FIDO U2F specification. Is this just another 2FA option, or is this significantly better than solutions ...
1
vote
1answer
110 views

How to cryptoanalyze a one time pad that uses a plain text document as the pad?

I have read that in order for a one time pad to be truly secure, the pad itself must be random data. Given the practical difficulty of sharing a secure random pad, I was wondering what would be the ...
-1
votes
1answer
42 views

Can OTP 2FA be reversibly determined?

Please note: I'm not necessarily talking about what happens when one shoulder surfs someone inputting a OTP. I'm fairly confident that it's nearly impossible (or extremely impractical) to guess the ...
3
votes
1answer
462 views

How do OTP USB sticks work?

I just discovered the YubiKey NEO which seems like a pretty awesome device for maintaining security for a variety of different things including computer login, SSH private keys, GPG private keys, and ...
2
votes
4answers
324 views

One-Time-Passwords resist against bruteforce attacks? Immune Alternative?

Does a One-Time-Password like Google Authenticator or YubiKey protect against brute force attacks with unlimited computer power? If not, what algorithems are immune to bruteforce attacks against ...
0
votes
1answer
151 views

Storage of the One Time Password Seed

I'm a student and I'm working on an OTP authentication systeme based on OATH using smart phones as tokens for the clients. My problem is the protection the OTP seed at both client and validation ...
1
vote
1answer
59 views

Verification code generation and expiration

I am trying to implement an application that includes registration, In order to register to the system the user shall enter his organization ID number let's say. To verify the user identity, a ...
0
votes
1answer
160 views

Idea for an algorithm to authenticate users with zero-knowledge-proof [need thoughts/review]

I have an idea for an algorithm. I don't know if I made any mistakes and need some extra thoughts/peer review on it. This would work as an (almost)zero knowledge proof for sending passwords that can ...
2
votes
1answer
231 views

What are the typical ways to generate a One Time Password?

I'm looking for the typical ways to generate a One Time Password. I know about the HOTP and TOPT. But, in my case, the problem is that the "server" only has a display as interface and the ...
0
votes
3answers
443 views

Is it possible to use OTPs for WI-FI?

Is it possible to configure an access point to use OTPs for authentication and encryption ?
0
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4answers
169 views

Why must every OTP be unique

All OTP systems that I have observed, send a new OTP every time a user requests for an OTP. (for example whatsapp) Only the latest OTP is valid and an OTP can only be used for X hours. I am wondering ...
0
votes
2answers
98 views

Are there any flaws in my design for a paper-based OTP grid?

I'm trying to implement two-factor authentication on the cheap for a website of mine. My bank uses this sort of grid-based OTP system, so I wanted to emulate it in my application: Cards are ...
10
votes
2answers
1k views

LastPass Grid Authentication vs Google Authenticator which one is more secure?

[Being a LastPass user] recently I moved to Google Authenticator instead of using Grid Authentication as a 2-factor security. For me, finding and filling letters from such a dense matrix is a rather ...
11
votes
3answers
1k views

What is the risk and mitigation of accidentally typing a YubiKey password in an open forum?

I have a YubiKey in my laptop (for testing) and accidentally broadcast my YubiKey password out to the Internet. Since this is only a test key, and has no access to anything of value, here are some ...
0
votes
1answer
79 views

“Reverse” approach to one-time key generation

Suppose we have a master key, and we want to encrypt some file(s). We then generate one-time key for that file, use it to encrypt file contents, and finally encrypt one-time key using master key (with ...
2
votes
1answer
620 views

Is Dual Factor possible during boot with whole disk encryption on Mac FileVault 2

Mac FileVault 2 is the default disk encryption for newer Macs that occurs in the EFI pre-boot phase. The challenge here is that most smartcard drivers are loaded after the OS loads. Is anyone aware ...
1
vote
1answer
57 views

Issues of using HOTP w/ iteration window

I am using HOTP to generate OTP to validate a request, in order to prevent replay attacks. I'm thinking about using a window of 10 (or so) iterations to accommodate a possible mismatch in the counter ...
4
votes
2answers
685 views

Is OATH TOTP and / or Google Authenticator vulnerable if an attacker has (N) previous codes?

I'm not much of a ipsec initiate, so this is a bit over my head ... but I'm always willing to learn more. Are there any known attacks against OATH TOTP (Google Authenticator's / Authy's algorithm) if ...
1
vote
0answers
41 views

Is there a TOTP variant that does not require the user to type in a code? [closed]

We're considering a 2 factor TOTP solution on a mobile phone. However, it would be much easier for the user to somehow send the OTP to the server by pushing a button, rather than manually typing in a ...
4
votes
0answers
800 views

FIDO, U2F Compatibility

I've been following the FIDO standard (a consumer-friendly public-key system similar to SSH key pairs) and it appears that it's close to being complete: both Google and PayPal have been testing it ...
6
votes
1answer
230 views

Why does my bank bother asking basic personal questions to log in to online banking?

To log into my online banking, I have to answer a basic personal question such as "What is your mother's maiden name" or "What is your grandfather's middle name", as well as enter a one-time code from ...
-3
votes
1answer
297 views

Why don't we do dual password instead of forgot password?

You can see a link Forgot Password? nearby almost all login form. As I mentioned in question, Since passwords are completely protected from outside access unless owner reveal, I come up with this ...
1
vote
1answer
218 views

Are there any secure ways to store the secret key used in a TOTP scheme?

I'm writing a little webapp that demonstrates 2 factor authentication. I'm using the TOTP protocol as described in RFC 6238. In our scheme, we are storing, in addition to a b-crypted password hash ...
2
votes
2answers
704 views

Security evaluation of Vasco's Digipass Mobile SDK for OTP?

Has anybody worked with or integrated the Vasco Digipass Mobile SDK OTP generator into a custom mobile app for iOS devices? I am currently performing a full security evaluation of the solution ...