Questions tagged [public-key-infrastructure]

A public-key infrastructure (PKI) is a set of hardware, software, people, policies, and procedures needed to create, manage, distribute, use, store, and revoke digital certificates. In cryptography, a PKI is an arrangement that binds public keys with respective user identities by means of a certificate authority (CA). There are three main categories of PKI: Web / SSL certs, corporate networks, and Government ID / ePassport.

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PKI: How does CA certificate revocation affect leaf certificates?

I'm struggling to find relevant section in RFCs, and I hope someone here can help me. How does - per specification - subCA revocation affect leaf certificates issued from this CA prior to revocation? ...
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Wrong size for EC key pair

I'm using OpenSSL to generate EC key pairs. I notice that the length of the keys as displayed by OpenSSL are exactly one byte longer than expected for both private and public Key. The 00 (first Byte ...
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Does the CA create the public key or is it created by the requesting server and sent to the CA?

This link says that the requesting server creates the public-private key pair and sends the public key to the CA inside the CSR. However, DigiCert says: The CSR is submitted to a Certificate ...
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Mnemonic Seed Phrase Generation For Private Key Truncation

The below code block is capable of generating a mnemonic seed phrase. If I want to generate a mnemonic seed for a private key, is it then correctly understood that I should input the private key as ...
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Public key stored in server is different from what is shown in OpenSSL

I obtained an SSL certificate from LetsEncrypt for my web application using Apache web server. LetsEncrypt generated these 4 files: cert.pem chain.pem fullchain.pem privkey.pem As I understand, ...
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why CA use private key to sign a digital certificate? What is the logic behind sign a digital certificate with CA private key?

In general(PKI), encryption happens with public key and decryption happens with private key. But, how Certificate Authority sign a digital certificate with private key? How this can be validated using ...
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Where can I find a list of all government agencies with CAs in PKI root stores?

Is there a source that monitors popular root stores for CAs controlled by government agencies? There are several "root stores" that maintain a list of trusted root CAs. These root stores are ...
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How is the digital certificate sent alongside digital signatures?

Most tutorials on the net only mention sending the digital signature attached to the document, but without the digital signature certificate, it'll be impossible for receivers to verify the signature. ...
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1answer
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Does a password-derived public key authentication improve security over pure password-based authentication?

Despite best efforts it is pretty clear that most users reuse their credentials, especially for what they consider non-critical sites such as forums. While TFA does mitigate the potential damage of ...
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Why is it said that we can obtain a digital signature from a CA when all we obtain from the CA is a certificate?

Several sites, like this states that You can obtain a digital signature from a reputable certificate authority such as Sectigo But digital signature is something you create using a piece of text and ...
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What are the recommended mechanism to securely distribute private keys to thousands of servers?

I am asking this question because in this article https://engineering.fb.com/security/delegated-credentials/ there is a sentence stating "We securely distribute private keys to the servers". ...
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IEEE 1363 is inactive-reserved, having been withdrawn on 2019-11-07 : what does this mean?

IEEE 1363-2000 - IEEE Standard Specifications for Public-Key Cryptography - has been withdrawn on 7th November 2019 and is now in inactive-reserved status. What does this mean? Why was it withdrawn? ...
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Can I restrict a Certification Authority to signing certain domains only?

Is it possible to create a CA certificate (even unsigned), which is only allowed to sign certificates for specific limited domain(s), so that it can't be misused for other domains?
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How do I constrain Windows Smartcards for AD Authentication so that “anyExtendedKeyUsage” is not implied?

This document describes how there are 3 ways to constrain a SmartCard certificate The Enhanced Key Usage field defines one or more purposes for which the public key may be used. RFC 5280 states “...
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Why does generating a self-signed X509 certificate not require my public key?

Let's say I have an RSA (2048) keypair that I generated private.key public.key For testing purposes I'd like to generate a self-signed X509 certificate. My understanding of a certificate is that it ...
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1answer
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Is macOS installing known bad Certificate Authorities by default?

Today I was checking out macOS security and privacy guide, and when I looked at my keychain, I was surprised to find Startcom CA and Symantec CA trusted by default. Isn't this supposed to be ...
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Why do we need to sign the self-signed certificate?

When we add a self-signed certificate to a device's list of trusted root certificates, we're already trusting it. So, why should it be signed with the server's private key? Signatures only ensure ...
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While importing certificates in keystore, do we treat these like CA root certificates?

When we need to call an internal domain via HTTPS, Java doesn't allow it because it doesn't recognize the certificate that those domain web servers are sending (probably because those certificates are ...
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1answer
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Best Practices Setting Up an Enterprise PKI [closed]

I am interested in learning about setting up an (internal) enterprise PKI the right way. What's mostly clear to me is the technical part. Our PKI will implement an hierarchical trust model based on X....
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How do i produce keypairs for my users while implementing json web token

I want to check the integrity of my user information; that the information which my website server receives was indeed sent by them. From what I understand, json web tokens (jwt) is the way to go. I ...
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Man-in-the-middle attack in SSH when attacker copies the public key

If an attacker is able to gain access to the public key on a host server, they can setup a different machine between the client and the server, and place the key there. When clients connect via SSH, ...
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TLS- Concept of channel binding

TLS-Handshake is based on public-key cryptography for symmetric key exchange, pki for server-authentication and assume the user authentication is realized trough username and password in the ...
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Is CA the only way to securely share public key?

Is CA the only way to securely share public key - are there other mechanisms that are viable in practice? I guess if you had a trusted software deployment system that securely transmitted contents ...
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How can we exchange public keys between two servers in a secure way?

I have two servers with a pair of RSA public and private keys. We do not use a CA for the internal communication yet and therefore we need to exchange keys without CA. I need to establish a trust ...
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how to send prime and generator of diffie hell-men to client over network node js?

I am using crypto module of node js for exchanging key using diffie-hellman algorithm. server.js const crypto = require("crypto"); const alice = crypto.createDiffieHellman(512); const aliceKey = ...
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Is an identity certificate the same as a public key?

I'm new to public key infrastructure but I think I understand how public key encryption works, conceptually. So a public key is, by definition, public and not a secret. Recently when I came across ...
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What if an attacker gets access to public key through an insecure media in digital signature?

If A encrpyts the message and creates signature using his private key and sends through the network then only B with the public key of A can decrypt that message. But what if the attacker gets access ...
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How to generate a CSR (certificate signing request) for creating a limited CA (Certificate Authority) using LibreSSL?

Related to this (too broad) question: How to implement my PKI? I have a self-signed CA (ca0) I would like to create a CA (ca1) with limited power derived from that first CA. ca1 should only be able ...
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2answers
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What is a link certificate?

I read an article and there was a link certificate short introduced (about a half sentence). Now I want to know what exactly a link certificate is? Assumption: A link certificate is used, when an old ...
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Can I find a private key for a known encrypted file?

Let's say I create a 100KB file only containing 1234567890, that is, a known value. This file would be sitting on several folders as bait. Once a Rasomware hits the folder and encrypts this file (...
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Are AWS KMS and Google Cloud KMS's HSMs valid as Certified Qualified Signature Creation Devices?

I'm looking into digitally signing documents and planning to use AWS KMS or Google Cloud KMS service to create and manage the private/public keys. Underneath they use Hardware Security Modules (HSMs) ...
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1answer
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How long does it take for a gpg key revoke certificate to propagate to all public key servers?

I recently created a new gpg key just for the sake of learning the basics of public key encryption. Now, I'd like to revoke that test key so that I can go on using a more "permanent" key that is ...
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keyUsage Extensions on a Certificate Authority

I have a question about what key usage should I choose when creating a private CA (root or subordinate). I have inspected some root and issuing web certificate authorities and they tend to use ...
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Certificates and keys validity [duplicate]

I'm connecting to a server via TLS. My device has installed server cert, device cert, private key and public key. I read here validity SSL/TLS that TLS cert will last max 2 years. This means that ...
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7answers
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Extracting the PGP keyid from the public key file

Is there a way via an CLI tool or some kind of API to extract the PGP key ID from the PGP public key block? I found the hexa value of the key in the binary file, but I guess the position is based on ...
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2answers
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How can I create a new root CA and sign existing intermediate CAs without their private keys?

Is it possible to create a new root CA (just for myself) and use it to sign a set of existing intermediate CAs which I'd like to trust? If so, which tool can be used to accomplish this? The private ...
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1answer
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Compare fingerprints of gpg --verify for files download with / without TOR

From my understanding, except we meet the creator of an archive in person and verify the primary key fingerprint, we can never be sure, that the archive we download is really created by the person we ...
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I need to make a PKI infrastructure, but i don't now how to segment my CA

I'm currently working on a project where we have to rethink a PKI architecture, but we don't know how to segment the different CA_SUBs, do you have any recommendations?
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How to reset Windows trusted certificates store to its default [closed]

Over time I have installed several additional trusted CA certificates to Windows trust store, sometimes because an app pushed me to do so, other times for reasons of development and testing. Is ...
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How to efficiently deploy SMIME email certificates for entire domain with Google GSuite?

Google Suite Enterprise supports centralized SMIME email signatures. This allows for easy deployment across all devices. But besides an API, there's apparently no central management. And I couldn't ...
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0answers
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Can anyone send any certificate [duplicate]

I seem to be missing one fundamental point regarding Certificates and hoping someone can set me straight. It is constantly described that a certificate can be used for authentication and to ensure the ...
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0answers
43 views

Which CAs is more vulnerable to compromise or misbehave in the trust chain (Root, Intermediate or Issuing CA)?

From the academic and real-world scenarios which CAs are more prone to misbehavior or compromise by attackers (Root, Intermediate or issuing CAs)? What are the consequences after compromise? Are the ...
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1answer
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Does AWS KMS use HSM underneath by default?

Have a doubt about about how AWS KMS handles their asymmetrical/symmetrical keys. Does AWS KMS use Hardware Security Modules (HSMs) underneath by default? (cant find documentation that prove/dissmiss ...
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1answer
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Can I use any ssl certificate to sign and encrypt AS2 message?

I'm absolutely new to this topic of ssl certificates, so please be patient with me. My task is to install an AS2 communication with some business partner. Therefore we need message signing and ...
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3answers
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Threema: Are received messages exposed, when sender's private key gets compromised?

Note: This question is specific to the Threema Messenger, and relates to their implementation of encryption (using the NaCl ECDH implementation as per their docs). I refer specifically to their "note ...
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How to set up OpenSSH to use x509 PKI for authentication?

I do not mean simply putting the public RSA key of a x.509 certificate into ~/.ssh/authorized_keys - I'm looking for a way to set up a ssh such that x.509 certificates signed by a pre-defined CA will ...
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Why is /cacerts request necessary in RFC 7030 Enrollment Over Secure Transport?

In RFC 7030 Enrollment Over Secure Transport (EST) https://tools.ietf.org/html/rfc7030, the /cacerts request (Section 4.1 of RFC 7030) is used by the client to request the current CA certificates. The ...
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1answer
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What is the role of leaf certificate private key In TLS handshake [duplicate]

What is the role of leaf certificate's private key if this certificate is signed by the intermediate certificate's private key and the certificate signature will only be validated using its public ...
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1answer
104 views

ECDH_SHA2_NISTP256 (KEX) Algorithm in SSH - Vulnerabilities?

My organization within my company uses this KEX Algorithm in our SSH Implementation. Another organization within my company won't connect to our servers as long as this algorithm is implemented as ...
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Technical description of a self-signed certificate

I'm having a friendly debate with a co-worker as to the meaning of "self-signed" when it comes to PKI. We have an internal root and subordinate CA in our organization. We import the cert chain on ...

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