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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Is Spoofing a CA signed certificate possible?

I had never thought about this situation before, I may be completely wrong but I am going to have to clarify it anyway. When a communication starts with a server, during the client handshake, the ...
1
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3answers
2k views

RSA encryption : How to create “.arm” certificate file for Public key?

I am required to store a certificate as ".arm" file only for a public key that is intended for use in RSA Encryption. I am currently able to generate the public key as ".key" file. P.S I am new to ...
21
votes
4answers
7k views

Are there technical disadvantages in using free ssl certificates?

Note this question is related, except this one is about free SSL certs. There are providers who are offering totally free entry-level SSL certs (like StartSSL). I was wondering if they are ...
2
votes
1answer
141 views

Curious about best start for autoresponding Certificate Authority (CA)

I am just getting started trying to implement some internal PKI ideas, where my app would need a cert to 'sign' messages. Since this is all completly internal, we have some degree of trust, and I ...
2
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3answers
430 views

Transfer Client Certificate

What, if anything, could or would be embedded into a client-side certificate that would prevent it from "working" when transferred to a new client machine on a new network? Being unfamiliar with the ...
0
votes
1answer
282 views

Can I export my digital certificate to this emtec usb

It is said here http://www.emtec-international.com/sites/default/files/s530_aes_en_0.pdf 2048 bit RSA module: ready for PKI application SHA256 data hashing: ready for digital signature Does it ...
5
votes
1answer
1k views

Any reason not to use same key for multiple SSL domains on one server?

Assume I've generated a server key for use by Apache for SSL. The server will be handling several different domains that use SSL via unique IPs (no SNI). I want to generate a CSR for each domain from ...
13
votes
4answers
14k views

How are Chrome and Firefox validating SSL Certificates?

How are Chrome and Firefox validating SSL Certificates? Are they requesting data from an SSL certification website, like GeoTrust, to validate the certificate received from the web server?
2
votes
3answers
699 views

Please recommend best-practices documents for sharing encrypted data with non-technical end-users

Is there one, or several, "best practices" documents which cover in clear simple language how to share data among a non-technical support staff and non-technical end-users at various organizations? ...
6
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4answers
3k views

Can an intermediate CA be trusted like a self-signed root CA?

Is it possible within the limits of the X.509 specification to mark an intermediate CA as trusted for a specific purpose, e.g. to verify a VPN, HTTPS etc. server key, just like it would work with a ...
2
votes
2answers
98 views

Does it make sense that OCSP returns state for the signer CA itself

I have seen an implementation that in signature verification time searches for OCSP responses signed by the CA validating the status of the CA itself, so my question is if somewhere (maybe RFC2560) ...
7
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4answers
1k views

Alternative to “web of trust”

Let's say I have an SMIME platform where I want to easily establish trust across the entire world for a particular purpose, for example for sharing valid financial information. I think that a ...
7
votes
2answers
10k views

How to get public key of a secure webpage?

How can I get the public key of a webpage like verisign , etc. using HTTPS protocol?
3
votes
2answers
170 views

In practice, does crypto software accept a *.com or or even a *. certificate?

Assuming this will be done with your own PKI, and not a public trusted CA. Considering that *.sub.domain.com is valid, and so is *.domain.com is valid, is it technically possible to issue *.com and ...
3
votes
2answers
492 views

Mitigations for Windows clients that don't support OCSP Nonces

Windows 7 clients (and older) don't support NONCES, a key feature used in securing the revocation check. Without a NONCE a MITM could replay a previously signed response and alter the validation of ...
3
votes
1answer
511 views

Is the Netscape SMIME extension still required in a certificate?

Every Windows 7 host has a Trusted Root certificate from Entrust that has the "Netscape Cert Type" extension (see image) I'm comparing inter-operable S/MIME extensions and see a pretty diverse set ...
1
vote
2answers
188 views

S/MIME and Dual-use certificates

My assumption is that S/MIME almost always utilizes certificates as follows: My certificate can be used to allow people to encrypt messages and send them to me. My certificate (the same ...
8
votes
1answer
2k views

How does adding a random serial number improve a certificates' security?

This article says: "Finding collisions is a tricky process, since it requires you to muck with the bits of the public key embedded in the certificate (see this paper for more details). Also, ...
5
votes
1answer
12k views

What is updated with “Update Root Certificates” enabled? What is the equivalent in Windows 2008R2?

What root certificates are/are not updated when the following checkbox is checked? Additional questions If I manually remove a root certificate, will this service replace that very certificate? ...
0
votes
1answer
591 views

How do I constrain Windows Smartcards for AD Authentication so that “anyExtendedKeyUsage” is not implied?

This document describes how there are 3 ways to constrain a SmartCard certificate The Enhanced Key Usage field defines one or more purposes for which the public key may be used. RFC 5280 states ...
2
votes
1answer
4k views

Clearing IE temp files don't erase CRL history. How can this be purged?

Even after I purge all my Internet temporary files, I still see information when I type certutil -urlcache How do I purge this information?
2
votes
3answers
1k views

What is the most secure way to do OCSP signing without creating validation loops?

I'd like to enable the most secure OCSP validation that Windows 2008 SP1 and newer support. Based on the following information, am I required to implement id-pkix-ocsp-nocheck on my OCSP ...
2
votes
1answer
1k views

What are attribute certificates? Why would someone partition a certificate by reason codes?

In "How Certificate Revocation Works" a brief mention of Attribute Certificate and Reason Code partition is made: If validated by a client that supports partitioned and indirect CRLs, the IDP ...
5
votes
1answer
1k views

Can a certificate have multiple chains and multiple self-signed roots?

The following MSFT document has this paragraph: All possible certificate chains are built using locally cached certificates. If none of the certificate chains ends in a self-signed ...
1
vote
1answer
4k views

What are the OIDs (KU and EKU) necessary for Smart Card Authentication in Windows?

MSFT smart card authentication is listed in PKINIT RFC 4556 however I don't see any OIDs listed. Based on this and this KB article the EKU section of the certificate should contain "Client ...
17
votes
4answers
11k views

Checklist on building an Offline Root & Intermediate Certificate Authority (CA)

Microsoft allows a CA to use Cryptography Next Generation (CNG) and advises of incompatibility issues for clients that do not support this suite. Here is an image of the default cryptography settings ...
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vote
2answers
147 views

Does Convergence solve the problem of hacked CAs?

My question is about the Firefox AddOn Convergence. So my question is if it is possible for convergence to observe that a phishing-site which is verified by fake Certificate because a hacker of a CA ...
2
votes
1answer
1k views

openSSL Not Displaying all attributes

Here's a background of what I've done so far: I've been able to add a CRL to a self signed certificate using OpenSSL (see attached). But I'm not sure how to create an X.509 certificate issued by ...
4
votes
2answers
4k views

Is your PGP passphrase used to decrypt an encrypted private key, or needed in conjunction with the private key to decrypt the message?

If the former, then if the private key can be used to digitally sign messages, why doesn't your client offer to encrypt this highly sensitive piece of data? If the latter, then if someone had access ...
3
votes
1answer
1k views

how do extended validation X.509 certs work?

https://www.forumatic.com/ uses an extended validation cert. wikipedia.org's entry on extended validation certs says that a cert is known to be an extended validation cert if the OID in the ...
0
votes
1answer
966 views

URIs in the subjAltName X.509 extension

The subjAltTag extension for X.509 certificates can take in domain names, email addresses, URIs, etc. I was playing around with an X.509 whose subjAltTag had just a URI in it doesn't seem to work. ...
2
votes
3answers
829 views

why does the first certificate have a RSA public key in x.509?

Example from http://en.wikipedia.org/wiki/X.509#Extensions_informing_a_specific_usage_of_a_certificate 1st certficate - freesoft 2nd - CA thawte Don't we use the RSA public key from the 2nd ...
11
votes
3answers
2k views

Difference between Certificate Authorities

I've been wondering for a long time about is. There are many certificate authorities having different types of certificates. But even certificates of the same security level cost a lot more with one ...
3
votes
2answers
1k views

What encryption schemes require two or 3 private keys to read a message?

I would like to encrypt some data so that it can only be read if two or three people use a private secret to decrypt the data. What is the best / most modern way to accomplish multi-person ...
1
vote
1answer
112 views

valid intermediate certs not in browser

Say an X.509 cert is signed by an intermediate cert that's not in your browser. Maybe the root certificate is but not the intermediate cert. At that point it seems like a valid certification path ...
7
votes
4answers
3k views

What web browsers support OCSP stapling? Are the privacy and performance features the same?

OCSP stapling decreases the load on a PKI infrastructure's OCSP server by attaching a signed OCSP response to the target in a TLS connection. In addition it creates a more secure/private session ...
8
votes
2answers
804 views

X.509 certificate policies question

I asked another question about certificate policy mappings. This is a different issue. This is about Certificate Policies. To quote from the X.509 RFC: In an end entity certificate, these ...
2
votes
1answer
660 views

X.509 certificate policy mapping question

So I'm a little confused how X.509 certificate policy mappings work. So let's say the following depicts my cert chain: root CA ---> intermediary CA ---> client cert Would the root CA have a ...
7
votes
3answers
2k views

Why does OpenVPN require securely sharing certs with clients?

The ubuntu docs on OpenVPN have this part in the instructions: Copy the following files to the client: /etc/openvpn/ca.crt /etc/openvpn/easy-rsa/keys/hostname.crt ...
8
votes
3answers
1k views

Is it safe to store a single symmetric key encrypted with several different RSA public keys?

For the field-based encryption of a database containing sensitive information, I was thinking of the following design: Every user has a smartcard used for client certificate login. After login the ...
4
votes
3answers
565 views

Public key system confusion

I read the following about PKI: Using a public key system, a user may encrypt a portion of a document using his or her private key. This message will later be decrypted by the recipient using ...
14
votes
2answers
1k views

SSL fingerprint inconsistency: what does it mean?

I apologize if this is not the best place to ask my question on the stackexchange network, I couldn't figure out where to get enough attention and be relevant. Facebook provides a SSL host, it can be ...
1
vote
3answers
2k views

Firefox detected an invalid SSL certificate

February 14, 2012 UTC: Yesterday, I connected to a website of a VPN provider for which Firefox 8.0.1 on Windows 7 Ultimate x86-64 stated that its' SSL certificate is invalid. I saved the received ...
27
votes
4answers
2k views

What's the common pragmatic strategy for managing key pairs?

I have a small number of different workstations (plus client devices like iPhone) that I use for to connecting to numerous servers using SSH. Originally when I learned about PKI, I created a single ...
6
votes
2answers
772 views

Why would the downloaded certificate show a different end-date as compared to the same certificate when viewed online?

This is sort-of a follow-up to my previous question What fields in a suspicious certificate should I look at? Chrome just presented the warning icon against the certificate presented by ...
7
votes
10answers
3k views

How can I share files with other individuals using the cloud in a secure way?

I would like to use a dropbox because it is easy and convenient. But I want to encrypt the files with the public key of the intended recipient, so he will be the only one who can access the data in ...
7
votes
2answers
2k views

OCSP and CRLs: Specified in CA or client certificate?

Here's an example PKI setup: * Root CA (offline) * Issuing CA * Client 1 * Client 2 I'd like to specify a CRL distribution point for CRLs generated by Root CA, and an OCSP URL for Issuing ...
0
votes
1answer
364 views

Enterprise Encryption Considerations

What are the different aspects to consider for Enterprise Encryption policy? So far the resources I have are: https://www.owasp.org/index.php/Cryptographic_Storage_Cheat_Sheet ...
5
votes
4answers
429 views

What fields in a suspicious certificate should I look at?

Looking at a certificate for a web-site (in Windows/Google Chrome) I see it lists the following fields Version Serial number Signature algorithm Issuer Valid from Valid to Subject Public Key Basic ...
6
votes
2answers
914 views

Two certificates on smart card

I have a question regarding Swedish gov eID (but I guess it is a pki/smart card general question); Why is there two certificates/keys on the card? Background: In Sweden you can have a "citizen ...