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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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2answers
3k views

Certificate Authority RSA key expiration?

My understanding about SSL/TLS for HTTPS is that servers send their certificates to browsers and browser attempt to decrypt them using trusted CA public keys that are already presented in their store. ...
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1answer
680 views

What are the information signed by a Certification Authority?

What data does a CA sign? I know that in a certificate there is plenty of information like the serial number of the certificate itself, the X.509 version number, the user Public Key, the asymmetric ...
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0answers
53 views

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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1answer
100 views

Certificate revocation

When someone claims that the private key corresponding to the public key has been stolen, and sends to the CA a statement of this fact signed with respect to public key pk. Why doesn't the CA need ...
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1answer
137 views

Where x509 signature validation is concerned, what does the error “x509 certificate chain incomplete of leaf TP not found” mean? [closed]

I'm validating the x509 signature of an XML document and I encounter the following error: "x509 certificate chain incomplete of leaf TP not found" Any thoughts on what the impact is for a TLS ...
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1answer
1k views

How is the PKCS #10 signature generated?

I'm generating certificate signing request in iOS, which does not provide proper ready-made API for CSR generation. Now the library I have used for CSR generation produces the different signature for ...
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2answers
112 views

Are there example certificates available for test purposes?

Are there example certificates (PEM format) for testing available somewhere ? For test purposes I would need a certificate signed with SHAS256/ECDSA P-256, together with a complete chain to test ...
3
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1answer
45 views

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 ...
2
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1answer
107 views

Any case that can require to encrypt a certificate revocation list before distribution

As far as we know certificate revocation lists (CRLs) include public information so they do not have to be encrypted before distribution. Is there a case that can require to encrypt it before ...
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2answers
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Why is a CSR signed and which key is used for signing?

I know that a CSR includes a public key from which a signed certificate shall be generated. But why is the CSR istself signed and which key is typically used? For signing I need a private key, so the ...
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2answers
1k views

Parsing of X.509 certificates

I'm working on a firmware for a platform with limited resources with C as programming language. There are a set of cryptographic primitives to be implemented, including AES, GCM/GMAC, ECDSA, ECDH. ...
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1answer
68 views

Method to verify a signed archive's X.509 CoT

I am trying to understand the key high level details behind verifying trust when downloading an archive. This is my understanding of how it could be done: On the Software Developer side: Obtain a ...
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1answer
101 views

Is there a way to inercept encrypted https connections by mimicking a cert authority?

In this video, it is shown how encryption can be theoretically intercepted without the client noticing it. In short something in between the connection could make a handshake with the requested ...
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1answer
62 views

Same certificate for server authentication and authorizatoin in other system

I have a program which acts as a node in a larger system. Those nodes can be connected to form a tree. TLS with mutual authentication is required, which means that each node has it's own certificate. ...
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1answer
133 views

Can I discard a specific X509 signature from file?

I'm writing a program to sign files using X.509 certificates and .NET framework classes. My users can sign the same file more than once without any problem (like a revision process). So, a file may ...
3
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1answer
3k views

Extra attributes in a certificate signing request

When creating a certificate signing request, there is a part where openssl says "Please enter the following extra attributes to be sent with your certificate request". One of these is a challenge ...
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3answers
87 views

Is there a method/protocol to validate a self-signed certificate by comparing a shortened hash?

I'm working on a solution where an iPad should connect to a server software running on a laptop using TLS with a self-signed certificate that was automatically generated on the laptop during the ...
8
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1answer
32k views

Is PKCS7 a signature format or a certificate format?

I always though PKCS7 was a signature format. However, on the net I find several references to PKCS7 being a certificate format - for example, this talks about PKCS7 certificate: Extract raw ...
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0answers
46 views

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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1answer
186 views

X509 Cert exploit CA check

Assumptions Let's theoretically assume that a browser skips the check that a certificate it receives belongs to the stated CA (that's an exercise). How could I exploit this in order to impersonate ...
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3answers
2k views

X509 certificate

I am studying the X509 certificate structure and here is an OpenSSL configuration file for generating the certificate. ("sth" just mean the actual string is removed) ...
2
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1answer
357 views

Can (EC)DH keys be used as the signed content in X.509 certificates?

From Wikipedia's article on ECDH: The public keys are either static (and trusted, say via a certificate)… Also see this question on this very site. These indicate to me that a certificate (maybe ...
2
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1answer
458 views

Why does Apple create a certificate for my push notification key [closed]

Brief rundown of how Apple Push Notifications (APN) work: Generate a keypair, generate a CSR for it Upload the latter to your Apple Developer account and associate it with your mobile app In the ...
2
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1answer
234 views

CRL number generation sequence: can I use a time stamp?

RFC 5280 states that the CRL number should monotonically increase. I have seen this common practice of incrementing the CRL number by 1, every time a new CRL is generated. But can I use a Unix (epoch ...
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0answers
85 views

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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1answer
26 views

What will browser show when a user access website and website present certificate of some other domain with same top level domain [closed]

For example, User tries to access a.example.com and server presents abc.example.com with a.example.com not in SANs list. Will it be just a warning or an error?
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1answer
89 views

How is the root certificate transmitted to pc?

i understand that the purpose of root certificates and CA's is to ensure that the communication parties are who they say they are. But how is the root certificate acquired? Is it not possible that ...
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1answer
155 views

Would SHA-1 be safe for certificates with short validity?

There are articles floating around the topic of SHA-1 deprecation. The gist of it is that in (mostly) developing countries, people are still using mobile/computing devices that are 5 years old (or ...
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1answer
677 views

How to verify CA certificate from Yubico with openssl?

I'm going to verify the CA certificate from Yubico. I copied the whole certificate from -----BEGIN CERTIFICATE----- to ...
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3answers
743 views

How does the certificate trust model work in detail?

How does the whole achitecture between the certificate authority (e.g VeriSign) and its clients (e.g foo.com) work. How does my browser know that foo.com hasn't created its own certificate, wrote "...
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1answer
128 views

How are all necessary parameters shared between signer and verifier in the ED25519 signature scheme?

I want to use the ED25519 signature scheme in my application which requires frequent sharing of secret data between two entities in the public domain. I know that the Schnorr signature scheme has a ...
1
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1answer
630 views

Rogue CA Certificate MD5 Collision Control

Papers from Marc Stevens et al show that X509 certificates that rely on MD5 signatures can break the assumed security model, that is, it allows for a forged certificate to have the same signature as a ...
3
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1answer
128 views

X509 certificates: Two Algorithm Identifiers?

I'm wondering why there are two Algorithm Identifiers in a X509 certificate. One is in the "to be signed" part and the other one is at the end right before the actual signature. Are they used for the ...
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2answers
126 views

Certificate Path Verification of X509 Certificate

I have the trusted root certificate which I am validating using the self signed key. I also have the intermediate certificate, which i am validating using the root certificate. Now when i am ...
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2answers
297 views

Must root certificates be self signed?

Root certificates are normally self-signed. What is the reason behind that convention? I mean, one must trust the root certificate in a non cryptographic way anyhow.
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2answers
256 views

Authenticating code securely and generating a certificate

I'm working on a product with strong security. Essentially there is an App, downloaded from the iTunes App Store. When the App starts up, it generates a strong RSA keypair and stores it in the ...
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1answer
1k views

How is OID 2a 86 48 86 f7 0d parsed as 1.2.840.113549?

I saw that an RSA key, created by OpenSSL, contains the following HEX string: 2a 86 48 86 f7 0d 01 01 01 that HEX string gets interpreted as Object ID: 1.2.840.113549.1.1.1 It is obvious 01 01 ...
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2answers
249 views

Is the warning given by chrome warranted?

I went to a payment page on a site recently, and chrome was warning me that the page is possibly not secure, I have a very basic understanding of crypto but not enough to fully understand why this ...
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2answers
2k views

Where is Signaturevalue in Certificate?

Where is the Digital Signature value in my certificate? I can find Signature Algorithm and Signature Hash algorithm. Also why there are two fields specifying the Signature's Hash? With Signature ...
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2answers
1k views

TLS Handshake : Server authentication or only Server ‘s Certificate authentication?

I have some difficulty understanding the way in which the Server is really authenticated by Client in TLS handshake (in case of using RSA key exchange). When Client receives Server ‘s Certificate and ...
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1answer
877 views

SSL pinning - how to safely hide the certificate?

We are doing an iPhone app and read multiple forums which says SSL pinning makes it possible to avoid man in the middle as we trust our web services server through the certificate which will be pre ...
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1answer
112 views

Signature Verification: High level

I'm trying to understand how certificate signing and verification works conceptually. I know the classic example with asymmetric cryptography- the sender encrypts data with public key of receiver, ...
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1answer
188 views

Certificate for the public key

I am new to Network Security and learning about various security features like Diffie-Helmann and others. I understand that the Public key send by the server to the client needs to certified that it ...
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0answers
62 views

Compromised Issuing CA [closed]

I'm configuring a PKI infrastructure with an offline root CA and several issuing CAs. Among other topics, I'm struggling to decide how the revokation of an Issuing CA certificate works. My Root CA ...
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1answer
5k views

Trying to understand the use of ECC in TLS certificates

I was looking the certificate of this website: https://www.cloudflare.com that has an ECC based certification. I'm just curious to know if is possible to understand which elliptic curve is used and ...
1
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1answer
122 views

What should I think about these unique certificate serial numbers [closed]

I was looking at the serial numbers of the certificates for www.google.com and wordpress.com. Wordpress was listed by openssl as: 04:0B:D4:F8:25:88:C5 This serial is listed as the serial for both ...
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1answer
6k views

where should private and public keys be stored? [closed]

I am kind of confused whether should a newly generated key pair be stored in a keystore or in just a normal plain text file? From what I read from online source, there are serveral explainations ...
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1answer
152 views

How are messages from server secured when using SSL certificate

In case of using SSL the certificate server has a primary key and a public key that is published to all clients - as far as I understood. So in this case when message is encrypted by public key (on ...
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2answers
7k views

How does a certificate authority issue a digital certificate?

I am new to cryptography and I want to know the details of how a Certificate Authority issues a digital certificate. From what I know (please correct me if I'm wrong at any parts of my explanation): ...
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1answer
139 views

Why rogued certificate from hash collision is harmful

I cannot understand why rogued certificate is thought harmful though It can be used to impersonate some website. The attacker can craft a rogued certificate with different identities and public key ...