Questions tagged [certificates]

A piece of data used in public key cryptography (specifically public key infrastructures) that contains identifying information (i.e. email address or web address), a hash of a public key, and a digital signature that authenticates the data in the certificate. For questions specifically about [x509], [certificate-authority], or [public-key-infrastructure], please use those tags.

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Is distributing software with KeyStores as resource secure?

I'm working on a client / server application. I want to encrypt the communication between the two. This GitHub project served as a starting point for me. It uses SSLEngine to establish a secure ...
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What ciphers should I use in my web server after I configure my SSL certificate?

There are many great questions that ask what is the best certificate to use for a website; but once the certificate is purchased, there is also the possibility to choose or edit the Cipher list. ...
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What are MITM proxies used for in enterprises?

My company (like many others I assume), uses a "man in the middle" proxy with a personal root CA. Disclaimer : I'm not a security expert so perhaps I do not correctly understand what this network ...
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Why is 'avast! Web/Mail Shield Root' listed as CA for google.com?

I just noticed something weird in my browser: the certificate for www.google.com has been issued by avast! Web/Mail Shield Root. Should I be worried? I am using avast! Antivirus so it's probably a ...
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What is a reasonable default_crl_days value for OpenVPN CLR? Why?

I am having trouble finding a definitive answer (with a rationale) on what a reasonable default value for default_crl_days (in openssl.cnf) for use with OpenVPN. The current default is 30 days. But ...
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How to obtain a private client certificate

We have a fairly weird integration scenario where we need to connect the following two systems: 1) Partner's API Portal - the server, which uses MASSL authentication with a requirement that the ...
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1answer
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what is the maximum life-time for Let's Encrypt certificates

Let's Encrypt is one of the most popular TLS Certificate Authorities. I have conflicting information about its certificates life-time. In this link it says 90-days. In one research paper I read 1 ...
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2answers
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Four ECDSA P256 CSPs are available in Windows. Which one should I use?

According to Azure support case #116120515025419, the public datacenter only supports the following TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384_P256 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256_P256 ...
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2answers
172 views

Maximum number of certificates generated by a CA

What is the maximum number of certificates that can be generated from a CA? The use case is a VPN using certificate authentication and I would like to know what is the theoretical number of unique ...
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What are the risks of installing a root certificate from Facebook on your phone?

I read a TechCrunch article today describing a program Facebook has been running since 2016 where they pay users $20 in exchange for installing a root certificate run by Facebook. This immediately ...
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More clarity on Certificate, public key, hash

I'm new to this certificate and public keys. So I've a certificate. I exported as .pem. I opened it in textEdit and it looks like the below. I've used below command to see what this certificate ...
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2answers
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4096 bit RSA encryption keys vs 2048

Where do 4096 bit RSA keys for SSL certs currently stand in terms of things like CA support, browser support, etc? In the overall scheme of things is the increased security worth the risk of 4096 bit ...
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1answer
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Certificate not trusted in Root CA Store - does it still enable secure connection? [duplicate]

I'm a bit new with certificates and have been unable to find an answer on this. We need to place controls around an application that is accessed via URL, we have moved the URL to citrix, but the ...
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Using client certificate from a file and a key pair from a hardware token

The question is about TLS client authentication using a browser. I have been using a smart card to authenticate to certain web sites. However, the card is a bit old and for whatever reason importing ...
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1answer
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Is it possible to mitigate risks of using a wifi connection that uses a self-signed security certificate?

I don't really know anything about security certificates, and I tried reading about this, but couldn't find the answer. Edit: The hotel I'm staying in uses a login page for the wifi connection that ...
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2answers
207 views

How to approach 2 tier PKI RSA Root CA with subordinates that should support ECDSA

I have a situation for which I am not sure how to approach it. Basicialy I need to find out if it is possible how to issue ECDSA Certificates with a RSA Root Certificate. Is this possible? and how ...
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1answer
107 views

What is the benefit of signing an executable that is not a driver on windows?

What is the security benefit of signing an executable that is not a driver? How is the signature verified by the windows?
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1answer
386 views

Extract issuer public key from certificate pem file

I know that a certificate that's been signed by a CA contains identifiers for both the subject and the issuer's public keys: $ openssl x509 -in cert.pem -text X509v3 Subject Key Identifier: ...
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5answers
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How can I export my private key from a Java Keytool keystore?

I would like to export my private key from a Java Keytool keystore, so I can use it with openssl. How can I do that?
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2answers
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Is the root certificate issued from one Certificate Authority is same for all the requesting organisation?

Let me please explain the question a bit more through an example: There are lots of companies who have their certificates signed by Verisign (or any CA). I understand that Verisign signs these certs ...
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1answer
53k views

Is using “SHA-256 with RSA-2048 Encryption” a secure certificate hashing algorithm?

Is using "SHA-256 with RSA-2048 Encryption" a secure certificate hashing algorithm? I don't think it is. Two examples: nsa.gov [careers site] give.wfp.org
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Renewing self signed SSL cert without updating client

I have a server and a single client. I have full control of both, the client is not a distributed application used by the public. For various reasons, I'm having the client use HTTPS to communicate ...
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189 views

In what important ways can a digital signature be invalid?

I am trying to write some code to verify that a digitally signed file came from my company. I was horrified to stumble across this deeply buried answer on Stack Overflow, an out-of-left-field ...
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2answers
1k views

Creating root CA to issue certificates programmatically

I have to generate a self signed root CA and use it to issue to certificates programmatically. I am new to security and certificates and I think I am missing some pieces required to make the whole ...
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1answer
75 views

DNS entry defined only in HOSTS file - will browsers mark the SSL cert as valid?

I have a webserver hosting an application that is accessible to the Internet but only has DNS records on my corporate DNS server. We have a few contractors accessing this site from outside the ...
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2answers
135 views

How to check Google SSL certificate?

I encountered this error on Google Chrome on my Windows 10. I solved it by installing the certificate and now it is working fine. I wonder, how do I know the certificate I have is legit? That is, ...
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114 views

Proxying an Android application with Burp Suite

I'd like to proxy an Android application with Burp Suite. The application uses certificate pinning via OkHttp3. I solved this by modifying the source code, now the application accepts the certificates ...
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1answer
95 views

Sub-domains TLS certificates and wildcard certificate [duplicate]

1) Is it a good security practice to have a separate TLS certificate for each sub-domain? 2) Is wildcard certificate (i.e. one certificate for many/every sub-domains) a bad practice?
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1answer
544 views

can MiTM read server certificate in TLS1.2?

We have a client and server that works via TLS 1.2 connection. Client connects to server, client checks server's certificate, connection established. Question - can anyone who read all data packets (...
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1answer
3k views

How to generate a unique and uncopyable VPN certificate/key for a specific client hardware device?

The problem is : Nothing prevents the user to copy the certficate/key on a different hardware device and use it from a different hardware device... Is it possible to generate a really unique ...
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Using build time generated, self-signed certs for inter application authentication

I need to be able to authenticate requests between different applications I am responsible for. My company does have CA signed certs, but there are two problem with using it for this purpose. ...
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1answer
2k views

When can I commit an OpenSSL Certificate (.pem) to source control?

That is to say, in what cases does it make sense to commit .cer files, or a stack of .cer files in a .pem, to internal source control like SVN or Git? If it's just a list of signed public keys, I ...
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2answers
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Does Digital Certificate affect privacy of the user?

As I know the user use the digital certificate to identify himself for the others. Can a Digital Certificate to be use as unique identifier for the user to trace and profile user activities?
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OpenSSL generate different types of self signed certificate

Does anyone know how to use OpenSSL to generate certificates for the following public key types: DSA - For DHE_DSS key exchange. Diffie-Hellman - For DH_DSS and DH_RSA key exchange. ECDH - For ...
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1answer
48 views

Is the CN field on an SSL cert a secure form of authentication?

I'm using TLS client authentication for a machine-to-machine connection. In addition to ensuring the client has a valid cert, I'd like to have access control to ensure the request is originating from ...
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7answers
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Why would a school need to install certificates on student laptops?

This question indicates parents are to buy laptops for a school to install software and certificates. I am seeking to understand reasons for site certificates installation: Why would site ...
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1answer
99 views

Can cURL block a rogue CA?

I know which Certificate Authority (CA) my server uses for its TLS certs. My client system also knows who the CA is. When I use cURL, I can specify --cacert to specify a custom CA file to use, but ...
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1answer
30 views

What are the security differences between a service-signed client certificate and an out-of-band shared secret?

TLS allows for client certificate validation. Client certificates can be signed by the client, the service provider, or a trusted third-party CA. I'm talking about the middle option. At a glance, it ...
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1answer
779 views

How do certificates work in terms of encryption, hashing, and signing?

I think I might understand this stuff, but I want to be sure I've got the details correct. There is a lot of information out there on the high-level implementation of certificates, as well as the ...
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How to read Security Technical Details for Connection Encrypted [duplicate]

I'm doing some research on encryptions websites and could use some help. How do you read/interpret this connection detail: Connection Encrypted (TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256_256 BIT ...
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2answers
937 views

How to eavesdrop and decrypt the HTTPs communication of an IoT device?

I am trying to setup a MitM scenario between an IoT device and WAN. It is possible and quite easy to achieve same thing for the application run on a mobile device by setting my proxy server(Fiddler)'s ...
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1answer
337 views

Multiple Intermediate Certificates on openssl

I need to create multiple intermediate certificates so the chain would be like this root >> int 1 >> int 2 >> user cert. Till yet, I have created a root and an intermediate certificate (signed by ...
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0answers
85 views

X.509 Certitificate Authentication between Client / Server (REST Implementation Model)

Can you please list of advantages /disadvantages on X509 Certificate based authentication instead of traditional username/password model ? Architecture Scenario : Lets suppose i have Client ...
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5answers
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Are there technical disadvantages in using free ssl certificates?

Note this question is related, except this one is about free SSL certs. There are providers who are offering totally free entry-level SSL certs (like StartSSL). I was wondering if they are ...
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2answers
48 views

Can certificate signing requests be stored at the server to prolong existing certificates?

I want to build a PKI (public key infrastructure) to host certificates for users. My use case is, that I want to use the certificates for e2e encryption between the users. Users must be able to ...
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2answers
1k views

Why is it fine for certificates above the end-entity certificate to be SHA-1 based?

I have heard about the phasing out of SHA-1 based certificates for end entity use, and the steps that are outlined for Google Chrome to display progressively more aggressive warnings for SHA-1 ...
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1answer
1k views

OpenSSL - how to renew certificates in production?

Have a number of private network services deployed on different nodes outside of optionally encrypted mesh systems, like Docker or Consul. The services have high value and should communicate via TLS ...
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2answers
112 views

Is it okay to have your SSL cert showing when server is reached by IP?

I've been doing some research into SSL for a paper for school, so please forgive my ignorance and lack of experience in this subject. While doing my research I have noticed that some websites when you ...
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2answers
230 views

What is being verified in OpenSSL's SSL_get_verify_result

In OpenSSL the following function is used to verify certs. SSL_get_verify_result I looked at the manual here. But it does not detail what is being verified. Can you clarify to me what does this ...
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1answer
134 views

OCSP, CRLs, crlset - Revocation Delivery and Attacks

OCSP responses have a 'nextUpdate' field, which is the expected time for the new revocation update and that the current revocation can be considered valid. The revocations can be cached by the ...