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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1answer
43 views

Enforce weak RSA in TLS

I'm going to give a small talk on the mathematical background of RSA. My audience will consist mostly of software engineers and to make the mathematical stuff tangible, I wanted to demonstrate how to ...
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1answer
140 views

PKCS12 password of container and private key

As I understand pkcs12 defines a container structure that can hold both a certificate and one or more private keys. ...
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0answers
28 views

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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1answer
42 views

How is a digital certificate generated?

I understand that the role of a Certificate Authority is to SIGN (not encrypt) a certificate. The signed certificate will theoretically contain: Plain text of data, including the server's public key ...
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12answers
14k views

Who verifies the trust of certificate authorities?

Background I am a novice in the field of cryptography and cyber-security, and while studying asymmetric-key encryption, I learned about the potential of a man-in-the-middle attack. To mitigate this ...
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0answers
23 views

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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0answers
49 views

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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1answer
85 views

Create self signed certificate from modulus, private and public exponents of RSA

I have the values of RSA public exponent $e$, the secret exponent $d$ and the modulus $n$. How can I create (for example using openssl) a self-signed certificate using the RSA key $(n,d), (n,e)$? Is ...
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0answers
68 views

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 ...
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1answer
61 views

Observing cipher suites and certificate algorithms without man-in-the-middle

I manage a proxy server. Is it technically possible to observe and determine which cipher suite is selected between end points (client and server) without changing their SSL certificate, without ...
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1answer
81 views

Why do we need HMAC?

AFAIK, HMAC solves the collision problem of hash algorithms by mixing in a pre shared secret. Can't we just use the pre shared secret to symmetrically encrypt data and leave out the hashing?
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1answer
694 views

How android apk file signing works?

There are a number of pages on web to tell how to sign apk file for Android. But none I've found telling how it works under-the-...
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1answer
52 views

Is this pairing scheme for establishing trust between two devices with self-signed TLS certs secure from MITM?

Assume two devices (A and B) with self-signed TLS certificates (this part can't change). We want these devices to trust each other. One way to do this is to simply copy A's cert over to B's allowed ...
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0answers
34 views

what is the difference between self issued and an intermediate certificate

Hashicorp vault has an API they call Sign Self-Issued. The use case is for rotating root CAs. A user creates a new root self signed CA and then passes it to this API and what is returned is roughly ...
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1answer
92 views

What does (06) in “CRL Signing (06)” mean?

In "Certificate details -> key usage -> CRL Signing (06)", what does "(06)" in "CRL Signing (06)" mean?
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0answers
65 views

Do people sign my subkey?

So, I've generated my GPG key pair. Created a subkey for signing and a subkey for encryption. Exported the whole thing, removed my master key pair to a secure place, re-imported only the subkeys. Now, ...
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1answer
47 views

How are certificate status obtained on browsers?

There are two ways of checking the status of a digital certificate:- Offline Authentication (CRL) Online Authentication (OCSP, SCVP) Several browsers (like Mozilla Firefox) have given up the use of ...
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2answers
94 views

How are CRL implemented?

The source from where I learn states:- CRL (Certificate Revocation List) is the primary means of checking status of certificates offline. But I can't seem to understand how is it possible for a ...
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0answers
32 views

Pitfalls of wildcard certificates with unique key pairs?

I am having difficulty finding information regarding using wildcard certificates with unique key pairs. I understand if you duplicate key pairs across multiple servers and one becomes compromised, an ...
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2answers
323 views

What is cryptographic sealing?

While revising my CAdES library I encountered some "sealing issue" in digital signatures. The Win SDK signtool.exe has a /seal ...
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1answer
226 views

How is Cross-Certification implemented?

I am currently learning about Certificates in Public Key Infrastructure. Cross-Certification exists as an alternative because the concept of a single monolithic CA certifying every possible user in ...
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1answer
129 views

CSR signature using elliptic curve [closed]

We've been asked to generate a certificate signing request using elliptic curve and we can't use any third-party library as it's an embedded application with very limited resources). We are used to ...
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0answers
54 views

What security is provided by a certificate? [closed]

I've been working on the topic of certificates for a little while, and here is what I understand: A certificate is basically a public key + some data about the owner of the certificate + a signature ...
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1answer
453 views

Windows certreq full response file [closed]

I'm using the Windows certreq command line tool to submit a CSR for signing to a Windows Server CA. ...
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0answers
53 views

Include TSA Certificate in Timestamp Request

Im currently working on Timestamping and stumbled upon a parameter fRequestCerts/requestSignerCertificates/certReq that according to the documentations tells a TSA to include the certificate that was ...
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1answer
65 views

How are public keys securely and reliably obtained across the internet?

I've just decided to start learning all about PKIs, and I have come across what seems like a paradox. When fetching a public key from either a server or a CA, how can we be sure that the public key ...
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1answer
112 views

Understanding hybrid cryptography's concepts: signing and CA

After learning about symmetric encryption, public-key encryption, one-way hash, digital signature and digital certificate, I was tasked to think of an imaginary hybrid cryptosystem. I was thinking ...
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1answer
85 views

What is the RFC order of peer certificate verification, trust chain or expiry first?

If a certificate received from a peer: Is expired, has a valid signature, but from an untrusted root CA What error should be thrown? Untrusted certificate or expired certificate? I can't seem to ...
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1answer
87 views

What key is used to encrypt the certificate and certificate verify message in TLS1.3?

Which key is used to encrypt certificate and certificate verify message in TLS1.3? I could not figure out which one it is reading section 4.4.2 of RFC 8846 and I only saw a vague mention on page 11.
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1answer
204 views

How can I verify certificate signature algorithm in TLS 1.3 using PSS?

I've read this post but I'm still unable to understand some things. I'm trying to verify that the signature algorithm used in the certificate matches the proposed list from the client. (As it's ...
2
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1answer
570 views

How to identify RSASSA-PSS from rsaEncryption OID?

Following the RFC 8446 it states that: RSASSA-PSS RSAE algorithms: Indicates a signature algorithm using RSASSA-PSS [RFC8017] with mask generation function 1. The digest used in ...
2
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1answer
474 views

Find hash and signature algorithms used in an X.509 certificate signed with RSASSA-PSS

I'm trying to understand the new PSS scheme, but having trouble figuring out how to parse it properly. When receiving a certificate with OID of RSASSA-PSS, how can I know which hash and signing ...
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0answers
62 views

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 ...
2
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1answer
523 views

How to generate a certificate/PEM from specific plain text keys?

Is there a way to generate a certificate with a pre-stablished public/private plaint text keys? Explaning: I generated some keys on a web site for development propurses, but now one of the parties ...
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1answer
44 views

Why CA does not have to be online?

I'm learning publick key infrastructure and certificate authority. But I cannot understand below conecepts. Unlike KDC or public key authority, CA does not have to be online to provide keys to ...
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1answer
42 views

When a program using openssl library is using a certificate, does the server check if the issuer(s) are still valid

If I have a program acting as TLS server with a certificate signed by a CA, if one of the issuers in the chain becomes invalidated or the date expires, then how does the program using the certificate ...
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0answers
19 views

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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2answers
3k views

Why does curl need both root and intermediate certificates in order to securely connect to an HTTP server?

I have created a root certificate, an intermediate certificate, and a server certificate: ...
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1answer
255 views

Is the only use for the private key of a root certificate signing certificates issued by it?

A root certificate can be used to issue intermediate certificates. The private key of the root certificate is needed in order to sign any intermediate certificates. However, after that, we only need ...
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0answers
146 views

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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1answer
89 views

How does a receiver treat X.509 self-certificate with unknown the Signature Algorithm ID?

As I know X.509 self-certificate is a mechanism that the host generates public and private keys, the public key will insert to a certification and the private key will be used to sign the ...
2
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0answers
242 views

Revoke a GPG key using previously generated revoke certificate after renewd (change expiration date)

I have few sub-questions Do secret keys get expired, or just the public key gets expired? Do I have to back up the master sec key each time I renew it? For an ...
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1answer
169 views

Understanding certificates for public keys with subkey

I have a openpgp key with 3 subkeys: ...
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1answer
63 views

I am new to digital certificate 509V3 concept. can some one please clarify the below points [closed]

I am using RSA 2048 with SHA 256 primitive in certificate: How to verify the user certificate n + 1 with Root certificate n? why it is required to perform Certificate chain verification? How to ...
0
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1answer
954 views

Which algorithm should be used to replace SHA512withRSA? [closed]

We are working on the web application that is basically generating a self-signed certificate during the installation. It's a Java based app and for generation of the certificate we are using ...
36
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3answers
7k views

Does “Shattered” actually show SHA-1-signed certificates are “unsafe”?

Note: I am not advocating anyone continues using SHA1-signed certificates: they are dead as far as security is concerned and should no longer be used. I'm just trying to clarify my understanding of ...
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2answers
766 views

What exactly is the contents of the LDAP userSMIMECertificate attribute?

I'm trying to setup an LDAP with user certificates. I have already learned that certificates can be stored in either the userCertificate attribute in DER format, or ...
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0answers
48 views

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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1answer
53 views

Key derivation with implicit certificates

The big advantage of implicit certificate is their small size and fast processing. This article presents a way how to compute implicit certificates. In the end Alice is able to derive both her ...
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2answers
112 views

Self signed certificate for mobile app and backend from same company

My company's product is Android and iOS mobile app which connects to our own backend. All interactions of the mobile app are with backend developed by our own company. In such a situation, can the ...

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