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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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68 views

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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156 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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259 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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142 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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232 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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180 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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37 views

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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225 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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451 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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277 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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178 views

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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2k views

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: $A \leftarrow B: h(r), B, P_A(r,B)$ $...
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105 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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136 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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368 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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1answer
761 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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701 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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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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68 views

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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139 views

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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1answer
116 views

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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107 views

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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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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91 views

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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90 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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117 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 ...
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51 views

standard way of authentication via token

I'm relatively new to authentication and I'm using JWT.io in following manner. Server Side Once user logs in, I generate a token with userid embedded inside and ...
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366 views

Authentication on top of Bluetooth JUSTWORKS encrypted channel

I have an embedded device with which I need to establish a secure Bluetooth LE connection. Unfortunately, the device does not have a display. However, the device will have a private key whose ...
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138 views

Dangers of using AES CTR without authentication - can you recover the plain text?

I understand that if a system uses AES in CTR mode (or other modes) without authentication that an attacker can flip bits to try to get the system to do something it wasn't intended to do (or wasn't ...
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116 views

Authentication of short message based on 6-digit alphanumeric compare-and-confirm

I have two parties that want to communicate with each other based on a shared password. The protocol is using PBKDF2 (with HMAC-SHA256) to create a shared key on both sides (due to restrictions on the ...
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107 views

Key Distribution Center Key Protocol Analysis

As shown in the image, why is Circle 1 to be B and Circle 2 to be A? Why is not the opposite, that is, Circle 1 to be A and Circle 2 to be B? like this picture From my understanding, Notation B in ...
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Keys and key-stretching when authenticating requests?

I'm making a REST application and still a bit confused about this issue. basically, to authenticate incoming requests, I give out userId, issued timestamp, expiry timestamp (normally 3 months after ...
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54 views

cumulative secrets

Imagine a server with an authentication scheme that utilizes an element of randomness in new sessions (i.e. one that uses the secure remote password protocol). At the end of a successful ...
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118 views

Designing an AES-based protocol for controlling and acessing ioT boards via RF

I'm designing an open ioT protocol to be used on ioT boards based on Texas Instruments RF-based MCUs. These MCUs have an AES module to easily encrypt and decrypt AES content, so that's why I choose a ...
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My attempt of combining socialist millionaire and Diffie-Hellman. Is it any good?

I've come up with an algorithm to solve the socialist millionaire problem, but I'm not sure if the algorithm is secure. I wasn't able to find any flaw in it, but it seems too simple to be secure, so I'...
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172 views

EC based password authenticated key exchange protocol

I would like to know: What is the currently best (efficiency and security wise) known EC based password authenticated key exchange protocol? (i.e. is there any EC based protocol may be similar to DH ...
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802 views

Mutual authentication with Public Key and session Key

I am trying to understand two protocols for mutual authentication and if they are secure or not. $K$ is the session key, and it's calculated $k=H(TimeStamp)$. Are the following both cases secure? ...
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Performance analysis of roaming authentication protocol using pbc library

Recently, I have surveyed a few research papers related to roaming authentication protocol for wireless networks. For example: “Efficient Privacy-Preserving Authentication in Wireless Mobile Networks” ...
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68 views

Smart card Strong authentication / Verification ( fingerprints)

I'm trying to make a strong authentication software and embedded software in a java card. I have found many papers and publications about the subject… too much information to process and I'm working ...
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192 views

Challenge–response authentication which can be done in head?

Say we have door where you have to say a password to pass. If theres someone standing nearby he would hear the password and could also use it. So therefore the doorman gives you a different number ...