A public-key infrastructure (PKI) is a set of hardware, software, people, policies, and procedures needed to create, manage, distribute, use, store, and revoke digital certificates. In cryptography, a PKI is an arrangement that binds public keys with respective user identities by means of a ...

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Using a Public-Key-Encryption browser side to avoid PCI compliance

We're developing a web application in which certain not logged users (clients) need to send their credit card details to other users (merchants) - which, we'll assume, are PCI compliant. We are ...
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45 views

Is there a secret-sharing public-key-encryption-based service? [on hold]

I need to share some sensitive information with someone else who can only communicate via E-mail. I don't love the idea of sharing this information freely over email in plain text, so I was ...
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19 views

Export non-extractable private key from Keychain on OS X

I have a PKI certificate in Keychain Access.app on OS X 10.9, together with the private key. The manual page for /usr/bin/security indicates that there is a -x option for security import to specify ...
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40 views

Is it possible to distinguish between a SHA256 hash and an ecc256 key?

If an attacker were just given 256 bits, and they were either a SHA256 hash or a 256 bit elliptic curve key, would they be able to tell which one it is? Just out of curiosity, would they be able to ...
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269 views

How can we revoke all ssl certificates issued for our domain?

After having the hostmaster@domain.com email compromised, we found that someone issued a Domain Validated SSL certificate for our domain. Now we want to have all such certificates revoked. Is there ...
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51 views

How can I generate some public and private keys on both sides with low overhead?

We have an Authority Center (CA) generating some public and private keys for each client (more than one pair for each client). One method for sending keys to client is sharing a secret key between CA ...
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23 views

Secure access of web application on a newly created AWS instance using the associated keypair

I create an AWS instance using a private AMI (Linux) with an embedded web application (Jetty) which is activated on instance start. As soon as the instance is launched first time, I want the ...
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69 views

Encryption mechanism

I want to send data over the Internet securely. For that, I am using an public key of the receiver to encrypt the data. In this case, if an intruder in the network modifies the data, like placing the ...
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1answer
35 views

How to safely renew user and CA certificates in a PKI

I am currently developing my own PKI where x.509-client-certificates are issued by a public server. At the moment, the CA-public key is distributed with the binary and there are no routines for ...
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38 views

What's stopping DANE? [closed]

As I understand it, DANE (RFC 6698) is a promising candidate for addressing issues with current TLS Trust Anchors (i.e. Trust Anchors). My attempt at explaining the issue: Currently, CAs are ...
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2answers
54 views

What's the mitigation strategy for when a CA's private key is stolen?

I'm new to SSL/TSL and was wondering if you could walk me through the following scenario. Scenario Let's say I am one of a thousand websites that has a certificate signed by some certificate ...
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1answer
54 views

Is there any mechanism to audit which signed certificates are unrevoked?

We are currently using EasyRSA and OpenSSL to manage our user VPN certificates for OpenVPN. The process we have in place currently is: User generates a CSR on their laptop and sends it to us to sign ...
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56 views

Client Authentication Certificate Not Expiring, but “parent” cert IS

So I have a client-authencation cert installed on client PCs, which doesn't expire for 5 more years. Unfortunately, the cert on our gateway which is used to validate the client cert, expires this ...
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3answers
81 views

Trusting SSL and the Trust Chain

As we all know, when an SSL Certificate is assigned, there is a trust chain that is created for verify everyone from the Certificate Authority to the actual website's SSL Certificate. Thanks to a ...
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2answers
139 views

How to prove flyer was (not) authored by specific person?

Let's say we create a flyer in some desktop publishing software (e.g., InDesign, Illustrator), physically print it and post it somewhere. We don't want inauthentic claims of authorship. Is there a ...
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1answer
62 views

What should a client verify after getting a client certificate?

I have a client that generates a csr, sends it to a server, the server then sign it and return the certificate as a String. the String is then decoded to a x509Certificate (using Bouncycastle's ...
3
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1answer
50 views

What crypto prevents & detects “invisible” CAs? (e.g. in X509v4)

For this question, I'm calling an "invisible CA" one that Is signed by a root ca and exists as a 2nd or 3rd tier Is valid, not expired or revoked Has a different Public key than one that is ...
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2answers
30 views

determine X.509 certificate class

I am very familiar with OpenPGP but don't even use X.509 / S/MIME. I know that there are several classes for certificates (from email check to personal ID check). I would like to know how you ...
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1answer
35 views

MITM protection, key distribution

I want to make sure each of my apps users only get their own data, and that nobody tampers with it or sniffs it in a MITM fashion. Encryption of everything should be the solution, right? But how do I ...
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1answer
30 views

How to encode a username in PKIX certificate?

I was reading through RFC 5280, PKIX Certificate and CRL Profile, Section 4.2.1.6, Subject Alternative Name: The subject alternative name extension allows identities to be bound to the subject ...
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1answer
39 views

Are “Certificate Templates” used only as a “Template” or do they validate a certificate request?

I'm trying to learn how Microsoft Certificate Templates interact with a certificate request, and can only guess that they take on one of the two/three forms: They simply help the client create a ...
2
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1answer
90 views

Bastion host that allows jailed users to SSH but protects private key

Basically, I'm trying to let the user use a private key without having read access to it. Use case: Employee needs to SSH to a server in the data center. There is 1 private key for all servers, ...
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2answers
51 views

Data anonymization/ encryption requirement

I did check out the previous postings and didnt find what I was looking for- apologies if this is a repetition. I am working on an analytics engagement for a customer and he needs to share access to ...
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1answer
27 views

Temporarily suspending a Certificate Authority's Certiticate

The PKI RFC talks about revoking or suspending certificates. It also talks about revoking CA certs. However, I could not find anything about whether a CA or a Sub CA's certificates can be revoked or ...
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1answer
79 views

How do I get a third-party-signed ssl client certificate?

I've been given a requirement of providing a client certificate to authenticate between two application's web services. The other application (that I don't host) is requiring an SSL client certificate ...
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64 views

Should I use more than 2048 bits in my SSH-2 RAS Key?

I've been asked to generate a public key with PuTTY Key Generator. The default is 2048 bits, Should I add additional bits to the generated key? Or is it unnecessary?
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143 views

From a trust perspective, is renewing a CA certificate the same as trusting a sub-CA?

I'm trying to understand the validation logic that would occur in the following hypothetical scenario An unpatched XP user who trusts a list of root CAs. Those CAs in particular have been renewed ...
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47 views

Public key encryption vs Digital signatures

For same chunk of data, which one is faster? Public key encryption or digital signature? Confidentiality is not important. I am trying to achieve non-repudiation for the communication. Thanks!
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23 views

OpenTSA and PKCS11

We are planning to implement the time-stamping service(RFC 3161) using OpenTSA wanted to know If OpenTSA supports PKCS-11 (Cryptoki) to talk to HSMs? BTW: I did not find documentation or much ...
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1answer
100 views

x509 serial number - hex or decimal

When I run the openssl command openssl x509 -noout -text -in certname on different certs, on some I get a serial number which looks like this. Serial Number: 256 (0x100) On others, I get one ...
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1.3.6.1.5.5.7.1.12 Logotype extension - how can it be generated from openssl command line

If you look at this subCA Certificate from Verisign http://www.tbs-certificats.com/FAQ/en/495.html?p=en/495.html It has the following field 1.3.6.1.5.5.7.1.12: ...
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32 views

Openssl command line: How to get “Policy: X509v3 Any Policy” in a certificate I am generating through openssl

I am trying to generate a certificate through openssl which has the following line X509v3 Certificate Policies: Policy: X509v3 Any Policy But I end up getting X509v3 Certificate Policies: ...
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1answer
155 views

adding certificate that resides on smartcard to the microsoft store with private key ownership

how can we solve CryptAcquireCertificatePrivateKey fails with 0x8009200B when adding certificate from smartcard to local user store? in an enrollment system where users generate smartcard certificate ...
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1answer
52 views

what harm can a malicious ca do?

If ca's act in the interests of an eavesdropper, what is the worst they cold do? I guess they can decrypt traffic not using perfect forward secrecy and impersonate the server. Is this the case?
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60 views

Public e-mail Encryption Certificate

I'm quite new to this, so don't be too hard on me. I'm currently using the CipherMail MTA to generate e-mail encryption certificates. I created an own CA and public and private keys for our contact ...
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2answers
49 views

Risk in connecting wrong ssh host?

I've a ssh host key login setup in a remote server, for some reason, the DNS of that host is mapped to another server. So assume the mistaken host cannot be trusted, should I change my key?
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3answers
122 views

Is storing the private key and public keys in same directory on server recommended, like OwnCloud does?

Is this recommended or a good/normal practice? I think not. Because I saw that OwnCloud stores all encryption keys in one directory on the server. One directory contains the private key(s) and one all ...
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1answer
53 views

Trust on certificate authorities

If I as layman don't err, there are in banking controls, from both internal and national oversights, of the work done by the employees. These are apparently effective, since the details of ...
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3answers
55 views

Are Extended Validation certificates any more secure than regular ones?

Or are they just an attempt to get you to pay more money to a CA because it tells your browser to show the address bar in green with your organization's name? Also, what are the technical details ...
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1answer
33 views

Is it possible to create a SMIME only PKI that *can't* be used for SSL?

Assume I have a Root CA that I want to share with hostile untrusted 3rd parties. Then constrain this root using specific EKUs at the root. OID=1.3.6.1.5.5.7.3.4 ; Secure Email Next, ...
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3answers
57 views

PGP and S-MIME What is web of trust?

I'm studying network and system security and i came across the phrase Web of Trust! In cryptography, a web of trust is a concept used in PGP, GnuPG, and other OpenPGP-compatible systems to ...
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2answers
62 views

Authentication through digital certificates plus signature

While studying X.509 certificates, I've found that authentication is safer if I associate/combine one or more certificates with each signed message (certificate + signed message). The receiver of ...
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1answer
38 views

Resign root CA as SUB?

Imagine I have a Microsoft root offline ca running since half year, but suddenly I want to include it in my company hierarchy, resigning it with the company official root, But I need both continue ...
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4answers
2k views

Is there any reason someone wouldn't use a longer key?

Larger key sizes are said to be more difficult to bruteforce; is there any reason someone would then decide to instead use a smaller key? Is there any negative effect in using a larger key size, such ...
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1answer
65 views

ECC Public Key length differs from bit representation

A 256 Bit ECC key-pair (256 Bit is supposed to be the length of the public key) generated with OpenSSL using this command from the manual: openssl ecparam -name secp256k1 -genkey -noout -out key.pem ...
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24 views

How digital certificate works? [duplicate]

I am trying to understand the digital certificate concept , but I am confused , Below goes my understanding & question, We are using Digital certificate because if Bob & Alice share their ...
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1answer
53 views

Certificate pinning in a browser

I am trying to understand certificate pinning. Google started adding a whitelist of CA certs that they use for their certificates and if a cert for a google service is issued outside of this list ...
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3answers
78 views

How are public key certificates updated securely?

Let's say I get a new computer that's never been connected to the internet before. The first time I connect it to the internet, is it susceptible to a mitm attack while downloading its public key ...
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2answers
81 views

Certificate authority structure - best practices

I'm working for a company that sells software products to customers some of which do not have the resources and/or know-how to build and maintain their own CA (used for the SSL communication of our ...
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3answers
109 views

Are there commercially available hardware encryption devices over USB? [closed]

I'm designing a system where some combination of hardware and software (lets call it an appliance...) sends asynchronous secure archival to the cloud. By secure, I mean, AES-256 encrypted, with AES ...