Questions tagged [certificates]

A certificate consists of a public key and information about the owner (e. g. the name of a person or server).

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Creating colliding x509 certificates: Crafting RSA moduli step

I am trying to generate 2 x509 certificates with the same signature but different values in the common name field, based on md5 collisions, as it was specified in this paper (page 7). Now I have ...
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Shortest Path for Certificate Network

I was reading an example from my textbook about verifying a certificate from a client using a certificate network. The example in the book is as follows: A issues a certificate to B. A issues ...
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Software signing with openSSL

The company I work for wants me to implement some C functions to automatically sign their software. After doing some research I've found that openSSL is great for doing so. Before starting the ...
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Detecting revoked keys long after a document is signed

Scenario: A document is signed with a compromised private key, with a long-term time stamp. The normal expiration date of the key pair is D. The rightful owner of the key pair discovers the compromise ...
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X509 Name Constraints in a 3-tier PKI - setting at the intermediate CA?

I have been playing around with implementing a three-tier PKI recently. My PKI structure is as follows: Root CA Intermediate CA 1 (Name constraint: DNS .example.com, Email: .example.com, pathlen 1) ...
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TLS 1.3 key_share capture without certificate exchange

I am working on an investigation on TLS 1.3. I've came across an article of qacafe where they shared a TLS 1.3 handshake sequence. Wireshark capture. In this capture you see that in the Client Hello a ...
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Error to create PQ certificate in C - x509 certificate routines:X509_PUBKEY_set:unsupported algorithm

I'm learning OQS OpenSSL and I'd like to create a certificate with dilithium in C, using liboqs and OQS OpenSSL. This is my code (based on https://stackoverflow.com/questions/256405/programmatically-...
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Comparison Hash, MAC, Signatures, Certificates

I saw a table comparing Hash/Mac/Signatures in this post. I was wondering if I can integrate digital certificates into it like this: Hash MAC Signature Certificate + Signature Integrity Yes Yes Yes ...
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Self-blindable certificates + group signatures

I am searching for a scheme supporting group signatures and at the same time permitting the blinding of the message-signature pair. Let me explain. There is a certification scheme proposed by Verheul: ...
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Generate version 3 x509 certificate from version 1 CA

Please do forgive me for my naivety. I have inherited a legacy system wherein the CA which signs the certificate is of version 1. Is it possible to generate a x509 version 3 certificate which is ...
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is it possible to achieve authenticated key agreement without using PKI or pre-shared secret?

After reading different techniques to achieve authenticated key-agreement (X3DH, HMQV, Asynchronous Ratcheting tree, An efficient protocol for authenticated key agreement, I understood that all these ...
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Review: peer-to-peer encrypted communication

I'd like to ask you to review security of the following communication scheme: network is strictly P2P, based on DHT (peer discovery) root user can create a virtual private network (network private ...
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Sorted merkle tree versus rsa accumulator

When compared to sorted merkle tree and rsa accumulator, which one is the best? Rsa accumulator has constant proof and it adds/deletes at constant cost. What is the verification cost for rsa ...
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certificate revocation list file size

Crl files are growing linearly. I wonder with 10 revoked certificate, what is the storage size of crl file and so on. For every revoke certificate, how much increase the size of the crl?
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Keeping a backup of asymmetric keys with the help of a certificate authority without losing the privacy

First I'll explain the problem, then I will also give a solution(it might be wrong) I've found for it, you let me know what you think about this solution and whether you have a better one. Assume a ...
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GlobalSign cert in Trusted root for Google Services shows Sha1. Security postures

"GlobalSign" certificate in Trusted Root Certification Authorities for Google Services shows Sha1. Security postures are different than just 2-3 yr ago. At my home, router bought 2016, networked; ...
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TPM 2.0 Reissued EK Cert

Unlike the TPM 1.2 module, the TPM 2.0 specification allows the platform user to create own ...
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Benefits of using SSL certificate over a raw key pair for non-browser use?

For applications not involving CA signed certificates – or web browsers for that matter – it would seem to be easier to use a raw key pair if possible, rather than deal with potential formatting ...
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Certificate Master Public Key with Pairing

I am currently working on CipherText Policy Attribute Based Encryption (CP-ABE) scheme. If we see the scheme, we can notice that the Authority may generate a Master Public Key and a Master Private Key(...
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Direct Anonymous Attestation

Could anyone explain me Direct Anonymous Attestation in general terms. I have been trying to read the paper but I really cannot seem to get my head around it. It may seem like a dumb question but I am ...
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IX509Extension XCN encoding?

I understand from reading MSDN that the X509 v3 extensions must be handcrafted. This involves the CRL, AIA, name and policy constraints, policy mapping, private key usage period, and subject ...
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Multi key layered encryption verification

Is it possible to take some value text like “Hello World!” And encrypt it with a random key. Then take the encrypted message and encrypt it again with another random key. And so on… Then can you write ...
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Comparing digital certification and blockchain certification

I am trying to understand the benefits of using blockchain technology in document certifications such as university diplomas. I would like to know the difference between digital certification and ...
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Is it possible to extract a signature from a HTTPS webpage?

Let's say I want to prove to someone that a webpage claims X. I could take a screenshot, but it could easily be doctored. However, the webpage's contents are encrypted by the domain using its private ...
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certificate authority

hi guys, is there a pseudonym in the certificate ? , I read papers that use the certificate authority, and between the components of the certificate, there is a pseudonym.
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What is the difference of having to use a ca.crt to verify a signed file vs the .crt used to sign it?

This seemed like the most appropriate place to ask this question so here it goes: I used to run a process that automatically generated a shim.key and ...
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Best model for client software encryption / decryption

I would like to develop a small solution (in C#) that must secure data exchange with an untrusted server. The model is that this software will run on a Windows client then encrypt data before pushing ...
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Any (proposed) internet standard (RFC) for trusted hosting of signed documents?

There's a problem with digitally signed documents - in particular that any print-out of them will be only a copy, not an original (by print-out I mean the print-out of the human readable form of the ...
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How is the identitiy of a subject in a Public Key Certificate verified by the Certificate Authority (CA)?

A general digital certificate issued by a CA might contain information about the individual/organization to whom the certificate belongs. As an example, consider this sample scenario: This PKC ...
Tabish Mir's user avatar
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What's the meaning of cached certificate revocation list and online certificate revocation list in X509RevocationMode Enum?

In this article, there are cached certificate revocation list and online certificate revocation list terms used. I tried to find ...
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Implementing ESignature and digital certificate

I'm having some issue understanding the mechanism of electronic signature and how implementing it Here what I understood, correct me if I'm wrong: (Client is here an android or ios device. Server ...
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Will CT (Certificate Transparency) override the use of CAA and/or DANE/TLSA records?

I'd want to know if some of these competing technologies has more chance to survive. It seems they are thought to solve a similar problem by different manners and I'd want to stick to the most ...
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How does DHE-RSA work and why is PFS guaranteed?

How does it work and why is forward secrecy guaranteed? I understood that it is not susceptible to a man-in-the-middle attack by using certificates in the beginning.
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How to validate the authenticity and integrity of an XML document?

I am working on a C++ desktop application that reads an XML (also created by my org) from a public server (does not require authentication). I would like to make sure that the downloaded XML has not ...
Vivek Kumar's user avatar
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Understanding TLS certificate

I'm newbie in the word of TLS, and need some verification about my picture. I can use TLS with 3 or 2 participants: 3 participants: Client, server, CA (certification authority). The CA is where the ...
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Derive anonymous dsa key-pair from two certificate authorities

Is it possible to derive a dsa key-pair based on two private keys from different/independent "Certificate Authorities" (ca1 and ca2) to sign s.th. which then verifies only that the signature is a ...
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Should a certificate be validated every time it is used?

In contrast to private keys, public keys don't need to be stored on a secure place. But what if somebody changes a certificate with a public key to just another one? To ensure certificate authenticity,...
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Verification of Certificates in a Chain

The question is not about mathematical cryptography but about the practical usage of certificates and their chained verification. Please let me know, if this is the wrong place to post the question. ...
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