Questions tagged [authentication]

Authentication is successfully validating that an entity you are communicating with is actually who they claim to be. The entity typically demonstrates who they are by showing they possess a secret that only they could know.

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How exactly does ASKE (Alpha Secure Key Establishment) in Zigbee work?

I am working on Zigbee security. For key establishment, some approaches are given in Zigbee. Some of them are: ASKE (Alpha Secure Key Establishment), ASAC (Alpha Secure Access Control), and SKKE (...
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Can “OPAQUE-over-TLS” authentication be optimized?

So while discussing the issues of password-hashing off-loading in our chat I noticed that it's easy to extend OPAQUE (CFRG draft) to essentially be a better standard password based authentication when ...
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What is the difference between mutual authentication and unilateral authentication both ways?

I am currently reading Engineering Security by Peter Gutmann, on page 7 he states: proper mutual authentication is quite different from unilateral authentication in both directions He references ...
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Is MITM possible after key exchange phase done successfully in RSA?

Is MITM attack theoretically possible after public/private key pair exchange is done successfully. Say Alice and Bob have genuine public keys of each other. Is MITM possible further during ...
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135 views

Difference Between an Authentication Token and an OTP (One Time Password)

I would like to better understand why some people use the term One Time Password and other Authentication Token. I have noticed that in academic circles, there is a differentiation between ...
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Password Derived Signature Authentication

I'd like to avoid sending user passwords over the wire. Would the following challenge response protocol be secure (served over TLS)? I know this is similar to SRP. Sign-up Client takes password and ...
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165 views

Is the “Pico” alternative to passwords vulnerable to man-in-the-middle?

Maybe someone has already heard about "Pico" by Frank Stajano. In short: It is a model for an alternative for using passwords for authentication and seems to be very interesting. Regarding the paper, ...
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266 views

Shared-secret authentication with implicit session keys?

Consider a system with producers (P), consumers (C) and a server (S) with two TCP ports open where a consumer connects on one port and a producer on the other. The server is just a TCP relay which ...
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37 views

Authenticate a session initialisation request

Consider a system where two devices are connected via a wireless encrypted channel. The channel requires manual pairing and the data passed over the channel is also encrypted using an ephemeral ...
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162 views

David Chaum's anonymous credential

I am a newbie in cryptography (I know the basic RSA, AES stuffs) and am interested in anonymous authentication systems. Looks like David Chaum is the godly figure in the field. I see lots of people ...
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Unknown authenticated encryption mode

I'm running through a protocol specification (LoRaWAN, pdf), and I'm puzzled by the crypto. The data is encrypted and authenticated in the following way: a unique 128-bit key is used; the plaintext ...
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241 views

Integer factorization based password authentication

After looking at this security issue at DjangoProject, I started to think in a password-based authentication that places the burden of PBKDF2 (or whatever is the hashing function) on the client. So I ...
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215 views

Authentication over the phone?

Are there any known good methods of performing authentication over the phone in a way that's not susceptible to replay attacks? The specific scenario that comes to mind is having an automated call ...
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60 views

How to look for implementations of universal hashing?

Being a physicist, I know very little about cryptography. In fact, the main two practical aspects I've learned so far are: Unless you're an expert, 1. Don't try to invent new cryptosystems and 2. Don'...
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“letter and key” security?

I'm sure there's a proper name for this, but I have no idea what it is. When my family fled Europe, one of the remaining items are a letter and a key from a bank. The general idea was that whomever ...
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152 views

Why is this authenticated Diffie–Hellman key exchange insecure?

I was searching for the information on authenticated Diffie–Hellman key exchange and found these slides. The author says, “Remember $$A\to B: (A, g^x, \operatorname{SIG}_a((g^x, B)))$$ $$B\to A: (B, g^...
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Can we say that password authentication contains registration phase, authentication phase and authenticated key exchange phase?

Authentication aims to validate the legitimate identity. The authenticated key exchange aims to establish a secure common session key. But can we say that password authentication scheme contains the ...
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Is the first Nonce exchange between Alice and Bob in Needham-Schroder key exchange protocol redundant?

For the Needham-Schroder protocol, assuming Alice and Bob are both able to guarantee each other's public keys (e.g. through a Certificate authority), the protocol is 1) A sends to B: $E_{publicB} [...
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Is timing attack practical in a web developer's perspective?

Let's say my server has a non-constant-time compare function for checking if the visitor has a valid session id. The time it takes for the comparator to run would be very insignificant, usually within ...
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258 views

AES-CTR and AES-CMAC using the same temporary key

Is it a severe security issue using a short-lived dynamic key for both AES-CTR and AES-CMAC? CMAC is generated on the cleartext and 32 bit of it are attached to the message (MAC-and-Encrypt) The key ...
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471 views

StoredKey in Salted Challenge Response Mechanism (SCRAM)

In SCRAM (RFC5802, page 8) the client generates ClientKey to server, which is a derivation of the original password. This is communicated to the server in a secure ...
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293 views

Proposed unidirectional authentication scheme

I've been looking around for a way to authenticate a client to the server and deliver a message, but in a unidirectional fashion - that is, the client sends messages to the server, but the server ...
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Does the initial exchange of random tokens in SKID3 authentication assure against replay attacks?

As the question suggests, I wanted to get a sanity-check on this issue... is it the case that the use of a random token exchange during SKID3 authentication itself constitute a prevention of a replay ...
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Challenge-response based on public-key decryption, why send public key

Quoting the handbook of applied cryptography, chapter 10.3.3 (i): Identification based on PK decryption and witness. Consider the following protocol: $A \leftarrow B: h(r), B, P_A(r,B)$ $A \...
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110 views

Reliability of a single-pass deniable authentication protocol?

I look for one-pass deniable authentication protocol with a short message payload for my project and find a solution: ...
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138 views

Is this a valid real-time authentication scheme?

The scenario in Alice/Bob/Cindy terms: Alice approaches someone she doesn't know, but thinks is Bob, and asks for some secret information. Bob doesn't know and doesn't trust Alice, but Alice says she ...
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395 views

Is TOTP or a timestamp encryption a better timestamp-based authentication token system?

Are there advantages to using TOTP over encrypting a timestamp with a shared secret, in cases where the readability or ease of typing the token are not important?
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880 views

Is it safer to use timestamp in REST authentication?

I am working on a personal project to build a REST authentication system which authenticate clients via three parameters: ...
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990 views

Can ECDH be used for authentication?

Is it safe to use ECDH for challenge-response authentication, with server key being ephemeral? The goal is that server does not store sensitive data (hashes) and allow clients to use additional ...
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What is the main difference between anonymous authentication and using an anonymous credential?

What is the main difference between anonymous authentication and the use of an anonymous credential? And when we should use them?
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53 views

HKDF Bit Security

I've always understood the bit security of hash functions to be related to their output size (eg. collision resistance). However, I recently came across a table from a Wickr blog post that lists HKDF-...
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Is there an implemented Id-based key exchange protocol?

I need to use some kind of authentication of the client during my key exchange process. During my research, in this article I learned about identity-based key exchange and authentication, and I was ...
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Is fingerprint authentication meaningless if the server/client is closed source?

I'm talking about when two chat users want to verify their identities via public key fingerprints. If the Client app is closed source, and we cannot see what it is doing, isn't the Server able to play ...
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OAuth(2) and friends

I've worked on low-level security (side-channel attacks etc.) for years and have a PhD in crypto. Web security is something I've never needed to touch beyond knowing how the TLS handshake works with ...
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Integrity for mixture of encrypted/unencrypted database fields

I have multiple blobs each (symmetrically) encrypted with its own randomly generated key. Now I want to encrypt these blob keys with user keys and store them in a database. A table could have the ...
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35 views

Very simple way of verification

In an application we need some way for a user to authenticate, but have the challenges of very restricted functions to use. Each user has got a 16bit-number he can't change. We want to calculate some ...
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57 views

Noise NK1 pattern identity hiding

In the official documentation for the Noise Framework there is a section with an overview of the identity hiding for each pattern. The numbering of properties there, obviously, from weaker properties ...
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21 views

How does AWS service verify the identity of the sender?

My question is regarding to : How does AWS Secret key and access key work The point 5: AWS service verifies the identity of the sender and integrity of the message by recomputing the HMAC code....
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TLS client authentication from static client image

I'm trying to implement mutual authentication for a TLS connection between a server (ONOS OpenFlow controller) and multiple clients (OpenFlow switches). I'm restricted in that I must create a single ...
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CHAP vs EAP-MD5

I started studying EAP authentication framework and I don't understand why was the EAP-MD5 developed. Why not just use the CHAP protocol ? To me they seem the same. Can you explain to me ?
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Why does 3-way authentication need the 3rd nonce to be stored?

In the following 3-way authentication protocol: A -> B: $N_a$ || B || Signature_KprivA B -> A: $N_a+1$ || $N_b$ || A || Signature_KprivB A -> B: $N_b+1$ || Signature_KprivA ($N_a$ and $N_b$ are ...
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How does the offline authentication work?

In these slides, offline and online PUF-based authentication protocols are explained in minute 16:30 and 17:30, respectively. I understand the way the online protocol works. Basically, the server ...
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Could you design something like a ring signature that uses website accounts instead of keys?

Ring signatures allow one to prove that you own a private key corresponding to a public key from a set of keys, without revealing which private key you control. This is useful if you are part of some ...
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Security of three-pass mutual authentication under ISO/IEC 9798-2

Based on 5.2.2 of the international standard ISO/IEC 9798-2 (http://bcc.portal.gov.bd/sites/default/files/files/bcc.portal.gov.bd/page/adeaf3e5_cc55_4222_8767_f26bcaec3f70/ISO_IEC_9798-2.pdf) Why ...
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Authentication protocol for communication with Arduino Uno

I am using an ECDH key exchange to establish a shared secret between an Arduino Uno and an Android device. For this purpose I am using this library and more specifically Curve25519. This is the ...
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Drawbacks of Schnorr Authentication that require Fiat-Shamir and Random Oracles?

I've been going through G. Maxwell's paper on the Borromean Ring Signature, and I don't fully understand this part on Schnorr Signature. If some could explain it more intuitively thank you. "...
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73 views

Cost of asymmetric signature checks vs password hashing

This is a question about standard every day web authentication. I have the following assumptions: one of the reasons public key user authentication is not used as bread and butter on the web is that ...
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PKI Challenge Response: why is $h(r) = x$ enough to protect against chosen text attacks?

I think the question was asked somewhere else but not answered very precisely. Quoting from the "Handbook of applied cryptography": Identification based on PK decryption and witness. Consider ...
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127 views

How does the authd protocol work?

So far, I have been able to research on what it is: authentication; authorization; using resource authd. I still have not come across a definitive answer or ...
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146 views

Possibility to combine keys for asymmetric signature creation

There is an asymmetric algorithm which signs with a private key and verifies with a public key. Private and public keys are created in pairs. Assume we have 2 pairs of private and public keys. Is ...