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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ValueError: Unable to compute factors p and q from exponent d [migrated]
I created a script that helps me decrypt RSA key but apparently it doesn't work for all public RSA certificates.
Here is the code:
...
62
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11answers
12k 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
19 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
39 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
44 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
37 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 ...
0
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1answer
58 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 ...
-2
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1answer
72 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
195 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
49 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
54 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
58 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
45 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
57 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
29 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
186 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
49 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
81 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
237 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
41 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 ...
1
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1answer
63 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 ...
0
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1answer
74 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
64 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 ...
2
votes
1answer
76 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
148 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
votes
1answer
440 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
votes
1answer
300 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 ...
0
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0answers
59 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
votes
1answer
284 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
43 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 ...
0
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1answer
39 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
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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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2answers
2k 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:
...
0
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1answer
132 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
134 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
74 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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1answer
190 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
129 views
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1answer
58 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
710 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 ...
34
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3answers
4k 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
571 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 ...
1
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1answer
50 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 ...
0
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2answers
86 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 ...
2
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1answer
841 views
How can Bob validate Alice’s certificate?
Suppose that Alice has a certificate CA1 << Alice >> issued by the certification authority CA1, and Bob has a ...
2
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1answer
59 views
Secure scheme to share symmetric key using asymmetric keys and certificates with N parties
I need to distribute symmetric AES key into number of end points which will use it to decrypt data. The AES key will be the same on all end points, it is not possible to generate unique on every end ...
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1answer
196 views
Secure Design and CRL?
I was at my College Security Lesson, the professor said that Certificate Revocation Lists (CRLs) violate some of the Secure Design principles.
Secure Design Principles:
Fail-Safe Defaults
Economy of ...
