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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670 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 ...
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64 views

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

I want to use ED25519 signature scheme in my application which requires frequent sharing of secret data between two entities in public domain. I know that Schnorr signature scheme has a key ...
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82 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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63 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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152 views

Certificate == signed public key

For primes p and q used to create a keypair, I understand that the following operation is used to create a signature: $M^d (\bmod\ N)$ where d and N have their usual meanings and M is the message. ...
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46 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 ...
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3answers
74 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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60 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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222 views

EC Public Key length in ASN.1 DER

I have two X.509 certificates in DER format. A: ...
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263 views

I've got my private key compromised. How does CRL work?

How does certificate revocation list (CRL) work? How can I send a request to the CA to add my current private key to the CRL, so no one except me can add my certificate to the CRL? Related: - How can ...
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434 views

Can you explain partial private key extract algorithm in certificateless Public key cryptography?

Related to the algorithms of certificate-less Signature approach of Al-Riyami and Paterson… Why is there a need for a "partial private key extract algorithm"? Why should it be needed when ...
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67 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 ...
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134 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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90 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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814 views

How can we get CA's public key?

To get a public key of some organization or someone we want to send an encrypted message to, we need to make a request to CA asking that organization's public key. CA then returns X509 certificate. It ...
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329 views

How do I sign data that's been encrypted using public key? (RSA)

I've received a public key to encrypt my data for the other end to decrypt using their private key. Now, they want us to sign the data as well to ensure non-repudiation. I thought that I should only ...
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36 views

How to set attributes to private key on PKCS#12 (key usage)

I make a certificate X509 with library Bouncy Castle on Java. I need set a Key Attribute to private key. ...
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15 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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36 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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28 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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61 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 ...
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181 views

Meaning of Signature hash algorithm field in certificate

I'd like to understand what is the meaning of this field, especially considering that when calling a crypto library to sign data the digest method is specified by the caller. For example, this simple ...
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288 views

x509 Certificate Signature

I've got a question about the signature of a CA. As I understand, the CA takes the public key of the client and signs it with his own private key by using "md5WithRSAEncryption" (like explained here: ...
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103 views

Unique assignment of X.509 certificate to each client

I'm trying to implement a short scale electronic voting application in a domain comprised of no more than 100 clients. System administrator is able to create new election instances and each client is ...
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334 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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94 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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2answers
48 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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1answer
24 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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166 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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68 views

Workaround to implementing Forward Secrecy

In the case where I am self-signing my digital certificates, if I just change my certificate (generate a new one) every week or month, will this have (sort of similar to) the same effect as ...
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12 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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15 views

Self-signed certificate becomes invalid after some time [migrated]

I have a web site hosted on IIS webserver. I've created a self-signed certificate for the web site and installed on a client machine. When I install the certificate to a client machine, I can ...
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39 views

How common are non-RSA digital certificates?

Is there a statistic available that shows just how common are DSA or ECC certificates amongst webservers? I know that RSA-based certificates are the most common, however I'd like to know, if there is ...
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19 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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23 views

Advantages of the general digraph trust model over the strict hierarchical model

Are there any advantages of using reverse certificates and the general digraph trust model over the strict hierarchical trust model as described here: In the digraph model each CA can generate ...
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282 views

RSA - Why should we sign hash rather than raw content? [duplicate]

Apart from obvious performance considerations, is there any mathematical or crypto reasons that imply that we sign a hash rather than a raw content ? I read that it was because the hash must fit in ...
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286 views

RSA and ECDSA Certificate Sizes

Is there a table (or a whitepaper from official sources) that compares the size of X509 certificates generated with RSA (starting from 1024 bits) and ECDSA (starting from 160 bits) ? Thanks for the ...
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518 views

What are the advantages of Certificate Authority and Key Distribution Center over each other?

I want know difference among them. What are advantages/disadvantage of one on other?