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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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Where shall we use authenticated encryption mode?

I learn from wiki that authenticated encryption mode includes OCB, CCM, EAX, GCM and so on. Does it mean that when we want to authenticated encrypt then we shall use these modes? But these modes don't ...
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Digital Signature Password verification

I currently have this TOFU protocol: First connection: Client generates salt and inputs a password Client saves salt Client hashes password with argon2 and salt Client generates Ed25519 keys Client ...
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How can users be authenticated without revealing their identity on a massive scale?

I want to create a system where a user can be authenticated without revealing who they are. I assume I have a list of public keys for all users (E.g. government issued). Ring signature could be used ...
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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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101 views

What is the security concept in printer cartridge?

Based on this datasheet or this patent, one of the usage of PUF is printer cartridge identification and authentication. I was wondering why printer cartridge needs identification and authentication. ...
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43 views

How can I get select messages ciphers for salsa20poly1305 for unit tests?

In order to avoid memory errors, I always write safe C++ wrappers with strong type-safety for any C encryption library I use. To test my wrapper of ...
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38 views

How can I follow the validation and verification recommendations of the NaCl (sodium) secretbox library?

I was advised to use crypto_secretbox_xsalsa20poly1305 due to its simplicity and because it's safe against timing attacks. I'm reading the secretbox tutorial, and ...
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How to implement correctly a “secure” authentication protocol? [closed]

Due to my lack of knowledge in this matter I am facing some problems to identify which features are sign of a bad implementation of a symmetric authorization application. As I am concerned the system ...
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76 views

Why CBC-MAC encrypts at each step

Considering CBC-MAC as: $\qquad H_0 = IV = 0$ $\qquad H_i = E_k(P_i \oplus H_{i-1})$ $\qquad MAC = H_n$ What are the properties that makes this "safer" (less ...
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68 views

How simple hash provide message authentication?

This structure provides message authentication. My question is if someone finds the key he can simply change the message and compute new hash according new message and send it to the receiver. If so, ...
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59 views

Timestamps, sequence numbers, and nonces for replay attack

What are the best practices or standardized methods to prevent replay attacks in a simple server client setup (preferably where the server is stateless) ? When should timestamps, sequence numbers, ...
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1answer
41 views

AES, CMAC and “3 pass authentication protocol” Explained

I am struggling a bit to understand how authentication systems are properly used in NFC tag environments so I'm posting this thread to clarify some concepts.(In advance, this is not my field, so ...
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1answer
62 views

How do i approach file encryption using encrypt-then-mac? [duplicate]

I'm programming a cryptographic application that encrypts files, locked with the password the user supplies. It's not intended to be used in production. It's a project for me to learn more about ...
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1answer
71 views

I don't want to store passwords, can I use them as an encryption key for another field?

I'm not a 'cryptographic' anything, so if this is a super-dumb question please let me know (politely). So here's the deal, say I don't want to store passwords because that opens me up to all sorts of ...
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How can a node establish pairwise shared key with other nodes using its own polynomial share together with other's public values?

A server has a symmetric bivariate polynomial $ F(x, y) = \sum_{{i,j}=0}^{t-1}a_{i,j}x^iy^j$ $\in GF(p)[X, Y] $ of degree $t-1$. For simpliciy, $ F(x, y) = a_{0,0}+a_{1,0} x+a_{0,1}y+ a_{1,1}xy$ mod ...
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Does the AES-KW (Key Wrap Algorithm) perform authenticated encryption?

The RFC for AES-KW doesn't actually mention authentication, only integrity, where the unwrapping/decryption process should produce an identical IV of ...
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Are key files good authentication?

Let's say $p$ is the pool of files in a folder. And $k$ is the files in the pool that are "key files" for authenticating in a service. Note: The order of the key files matter. Then we have $c$ which ...
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Difference between double unilateral authentication and bilateral authentication?

What is the difference between applying bilateral authentication once and applying unilateral authentication twice?
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Two-party symmetric key establishment protocol

I need a symmetric key protocol that will mutually authenticate and establish a new short-living session key between two parties that have a pre-shared key. Unfortunately, I have not found any ...
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How to encrypt numeric data on a ticket

I have a customer with an existing ticketing system that generates tickets for events like theaters, movies, football and so on. The information in each ticket is encoded in a 16 decimal digit ...
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1answer
96 views

What is the difference between static and dynamic tokens?

First, what is the difference between hardware and software tokens? Tokens are "what you have" for example a car key or a chipcard. This would be (I think) hardware tokens? But what are software ...
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Privacy Preserving Authentication Protocol

I am learning this new concept. I found different algorithms (similar bases) in different papers. example1 (Fig. 1) example2 (Fig. 5) I was wondering if some one can explain it in simple words. ...
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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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2answers
78 views

Authentication without decrypting the password?

To my knowledge it works like this: The server receives the username-password values over a secure & encrypted channel. The username-password values are decrypted in the server and are present as ...
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Most energy-efficient authentication protocol?

I am looking for a cryptographic protocol that is as energy-efficient as possible. I am talking about battery drain. Alice wants to do a mutual authentication with Bob. Maybe symmetric is good, maybe ...
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Is my method of identifying remote ZMQ clients secure?

ZMQ provides a CURVE based authorization / encryption system based on certs/keys. After endpoints are authenticated to the server, they can send an "identity" with each request. Unfortunately they ...
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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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1answer
243 views

Fiat-Shamir zero knowledge protocol

In Fiat-Shamir protocol, the final calculation is $$y^2=x\,v^c$$ Where $c$ is the random $\{1,0\}$, $x$ is the witness and $v$ is the public key $s^2 \bmod n$. My questions are: What stops the ...
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Rolling Code via Encrypted Index vs Pre-Generated Keys

I am planning on designing a system that needs a password to be operated, using a rolling key. Now I am facing two options, as far as I am concerned: Having an index saved, which will be incremented ...
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295 views

Message authentication vs entity authentication

Does message authentication authenticate the entity? If the answer is "No", because message authentications like MAC work with the shared symmetric key, then my second question is: Does a message ...
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1answer
89 views

Definition of Short Authentication String

I am studying for my cryptography final and I passed by the following term: short authentication string. Please, can anyone explain it to me, thank you very much.
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499 views

What is the use of SCRAM-SHA-256 (over SCRAM-SHA-1)?

The Salted Challenge Response Authentication Mechanism (SCRAM) specified in RFC 5802 can use arbitrary hash functions to operate. The base version from RFC 5802 uses SHA-1. From my understanding, ...
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1answer
52 views

Two-way secret sharing for authentication?

Secret sharing, using methods such as Shamir's Secret Sharing allows for t out of n shares to recreate a secret. For authentication, the secret can be a user ID. A client with a logged-in user can ...
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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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Disadvantage of the using a counter within plain text for encrypting with AES256 and authentication?

What if we use a counter within the plain text and then encrypt the plain text with aes 256 to encrypt & authenticate? For example: encryptAES(32bit_counter+plain_text_of_96bit); or encryptAES(...
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90 views

Is this device authentication method (using AES-256) secure?

Let's say we have: client_id_ran: 256 bit random text (chosen only once for whole system) used to generate client_id by ...
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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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1answer
162 views

Are SSH key-pairs an example of a zero knowledge proof?

Quoting from source, authentication using SSH key pairs goes something like this: 1) The client begins by sending an ID for the key pair it would like to authenticate with to the server. 2) ...
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1answer
216 views

How does the user get the private/public key with HMAC based request signing?

I need to implement a HMAC signing of requests and I have read this article which explains the basics of what it is and how to achieve on theory. https://blog.andrewhoang.me/how-api-request-signing-...
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1answer
177 views

What would happen if the last message in a three-pass authentication protocol was undelivered?

I did read some articles about the protocol but couldn't figure out what would happen. Would the two parties be unable to verify each other? Or would it be something else? based on the international ...
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1answer
76 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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1answer
46 views

Can a Message Authenticaty Code recover original data from corrupted data?

I am new to cryptography and have been studying for Dan Boneh's Stanford Course on Coursera, after going through encrytpion and decryption I've started the integrity portion of the Course. Sir ...
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2answers
111 views

Cryptography scheme to prove you really are the author for something

Say I'm a researcher like Satoshi Nakamoto that wants to stay anonymous. I want to publish documents and sign them somehow. A few years, I want to reveal my identity and prove it was me who was ...
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4answers
346 views

JWT Login Security

I am new to security and I am wondering if JWT is secure enough. From what I have read online the flow goes like this: Clients log in by sending their credentials to the identity provider. The ...
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Asymmetrical encryption with multiple sufficient key-pairs [duplicate]

I have the following requirement: There are N public/private RSA key pairs. The encrypted data must be decryptable by any of the private keys alone, but not by any other key. For encryption, the ...
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2answers
60 views

How to calculate a multiple-character checksum for authentication using a tabula recta?

I am not sure if this is possible to do using a tabula recta, but I would like to know how to calculate a multiple-character checksum of a text. For a single-character checksum, it's easy. You just ...
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1answer
114 views

Login security and plaintext of a password stored in Argon2i to derive a key via halite safe?

I'm using Symfony 4. I have set parameters on all my Argon2 stuff below so that it takes 1s per iteration. This website is supposed to encrypt HIPAA information. Basically I have a table like this <...
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1answer
125 views

How is ZKPP better than signing nonces?

I am trying to understand the use case for zero knowledge password proofs. Clearly, it is not ideal for a remote server to store a password hash. Then I need to upload the password to the server for ...
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1answer
443 views

How to generate tokens from a secret key?

The problem is simple: I want to be able to spit out 256-bit "tokens" that only I could've produced because I know my secret key $s$, and given any number of these tokens, no one can figure what $s$ ...
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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. "...