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 ...
173
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3answers
45k views
How does SSL work?
How does SSL work? I just realised we don't actually have a definitive answer here, and it's something worth covering.
I'd like to see details in terms of:
A high level description of the protocol.
...
117
votes
7answers
6k views
How do certification authorities store their private root keys?
Knowledge of a CA private key would allow MitM attackers to transparently supplant any certificates signed by that private key. It would also allow cyber criminals to start forging their own trusted ...
41
votes
10answers
2k views
Why do we not trust an SSL certificate that expired recently?
Every SSL certificate has an expiration date. Now suppose some site's certificate expired an hour ago or a day ago. All the software by default will either just refuse to connect to the site or issue ...
28
votes
4answers
14k views
What is the difference between an x.509 “client certificate” and a normal SSL certificate?
I am setting up a web service through which my company will talk to a number of business customers' services. We will be exchanging information using SOAP. I would like to handle authentication with ...
24
votes
3answers
813 views
A Different Approach to PKI
After yet another failure of the public key infrastructure, I was thinking about how broken the whole thing is. This business of undeniably associating an identity with a public key, and all the work ...
21
votes
3answers
624 views
What is an SSL certificate intended to prove, and how does it do it?
If I get an SSL certificate from a well-known provider, what does that prove about my site and how?
Here's what I know:
Assume Alice and Bob both have public and private keys
If Alice encrypts ...
19
votes
11answers
2k views
How feasible is it for a CA to be hacked? Which default trusted root certificates should I remove?
This question has been revised & clarified significantly since the original version.
If we look at each trusted certificate in my Trusted Root store, how much should I trust them?
What factors ...
16
votes
3answers
1k views
What happens when an Intermediate CA is revoked?
Currently I'm working on a certificate manager that allows our product to securely connect to remote webservices (over TLS/SSL).
For security, we use Certificate Revocation List checking (or ...
16
votes
4answers
4k views
How does PGP differ from S/MIME?
Is S/MIME an abstracted system for general MIME type encryption, whereas PGP is more for email? Why would I want to choose one over the other, or can I use both at the same time?
12
votes
4answers
3k views
how digital signature verification process works
I am not able to understand that how the digital signature is verified. I know that digital signature will be attached to the message and sent by sender to receiver. then receiver uses the public key ...
12
votes
2answers
357 views
Encryption and the “security time decay” of prior encrypted data
This question is on the assumption that any data once encrypted, may (eventually) be decrypted through
Brute force (compute power/time)
Exploits in the cryptography used
Theft of private keys
...
11
votes
2answers
2k views
How does RSA encryption compare to PGP?
On this answer ck says
RSA and PGP are different.
What you are essentially asking is how
do I run my petrol car on diesel? The
answer is you can't.
I would be interested in a more ...
11
votes
2answers
471 views
Which SSH security is stronger? 2 Factor or Public key
For SSH authentication, which is more secure?
2 Factor Authentication using a USB token/Google Authenticator(time based)
OR
Public/private key with password
Or could they be both used at the same ...
11
votes
3answers
9k views
Expired SSL Certificate Implications
What are the security implications of an expired SSL certificate? For example if an SSL certificate from a trusted CA has expired will the communication channel continue to remain secure?
11
votes
4answers
403 views
What alternatives are there to the existing Certificate Authority system for SSL?
Whilst the current CA system works very well for a lot of people, it does put a lot of power into individual CAs' hands, and makes a CA hack potentially devastating for customers and business. What ...
11
votes
4answers
2k views
What is certificate pinning?
I'm superficially familiar with SSL and what certs do. Recently I saw some discussion on cert pinning but there wasn't a definition. A DDG search didn't turn up anything useful. What is certificate ...
11
votes
1answer
670 views
How would I implement “Broadcast Encryption”?
I have a stream that I want to encrypt for broadcast to 10,000 subscribers. I know I should encrypt this data using a symmetric key; and also intend that this symmetric key will be rotated every 30 ...
10
votes
4answers
651 views
Why isn't OCSP required by default in browsers?
According to the following screenshot, taken from firefox-3.6.17-1.fc14.i686, Firefox has an option to fail closed when unable to connect to OCSP servers.
Can someone please explain why this isn't ...
10
votes
7answers
785 views
Can a HTTPS connection be compromised because of a rogue DNS server
If I'm visiting (just a desktop pc, client side) a site that has a valid HTTPS cert/connection, that can it be compromised if I'm using [not with free will, so e.g.: I'm "attacked"] a rouge DNS ...
10
votes
4answers
1k 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 ...
10
votes
3answers
1k views
Computationally simple, lightweight replacement for SSL/TLS
Target hardware is a rather low-powered MCU (ARM Cortex-M3 @72MHz, with just about 64KB SRAM and 256KB flash), so walking the thin line here. My board does have ethernet, and I will eventually get ...
10
votes
3answers
738 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 ...
10
votes
2answers
649 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 ...
10
votes
2answers
168 views
What does having an internal two-tier PKI protect against?
There are a lot of Best Practice documents that recommend having an offline Root CA and an Enterprise Subordinate CA that is signed by the root, for an internal Microsoft AD Certificate Services ...
9
votes
3answers
405 views
Multiple CAs signing a single Cert/CSR?
Just saw this suggested on Slashdot
So I've seen quite a few people wanting a switch to self-signed certs (who IMO mostly don't understand what making that secure actually involves), and an idea ...
8
votes
2answers
605 views
Are there really functioning quantum computers?
I saw this video on youtube on quantum computing. It says that a company called dwavesys has already made commercially available quantum computer. I checked on the website and it exists. I thought ...
8
votes
3answers
2k views
What are the risks of self signing a certificate for SSL
Let's say I sign a SSL certificate for myself, and I'm not using a certified CA. What are the risks and/or threats of doing it?
8
votes
3answers
323 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 ...
8
votes
2answers
2k views
SSL Certificate revocation check
In the SSL protocol I don't see where the certificate is checked for revocation status.
https://developer.mozilla.org/en/Introduction_to_SSL
Is the Certificate Revocation and Status Checking not ...
8
votes
2answers
3k 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 ...
8
votes
2answers
279 views
Is it okay to widely share the RSA key fingerprint for a host?
When you ssh into a remote box for the first time or if the remote host's key fingerprint has changed (from what's stored in your known_hosts file) you get a warning and you are shown the fingerprint ...
8
votes
3answers
561 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 ...
8
votes
3answers
483 views
Does the SSL encryption strength of a website really matter?
When looking to get an SSL certificate one is presented with a lot of options. For example lets take Network Solutions since they have a nice comparison chart.
Immediately there seems to be 4 major ...
7
votes
3answers
1k views
Certificate authorities for a PKI
Some people think the certificate authorities for a PKI should be the government, but others think certificate authorities should be private entities, such as banks, corporations, or schools. What are ...
7
votes
1answer
237 views
Why is there no Domain CA?
I was asked to deliver a signed SSL certificate for an IIS server for a client.
I have previously done this for the same client/domain before, so it start to seem like
an unnecessary expense to hold ...
7
votes
2answers
282 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 ...
7
votes
1answer
150 views
distributing files to VPN partners
suppose i've created VPN certificates for a certain VPN-RoadWarrior-Client, expressed in the files VPN-RoadWarrior-Client.key and VPN-RoadWarrior-Client.crt*, however VPN-RoadWarrior-Client is ...
7
votes
1answer
960 views
Renewing Microsoft Certificate Services Root Certificate
We currently have Microsoft Enterprise Certificate Server installed on a domain member machine which issues 1 year certificates to users for authenticating to VPN.
We'd like to start issuing web ...
7
votes
1answer
542 views
Moving from a one tier to a two tier Microsoft Certificate Authority hierachy
Right now we have a single Microsoft Enterprise Root CA which issues certificates to our VPN users for two factor authentication. We're planning to extend use of the CA to issue certificates for RDP ...
6
votes
4answers
688 views
What kinds of SSL certificates are usable for encryption?
I know that Verizon SSL certificates cost close to $600.
There are couple of cheap alternatives, but I never really understood why Verizon does not offer such certificates. Look for RapidSSL at ...
6
votes
3answers
188 views
Renew digital certificate
If I have deployed a digital certificate on a webserver and if it needs to be renewed then what steps do I need to follow? Will I need to generate a new longer public key private key pair? Why do ...
6
votes
2answers
397 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 ...
6
votes
3answers
148 views
Guarding against rogue certificates
There has been a lot of news recently about certificates being falsely issued (due to the issuing authority having poor system security!). Apparently the targeted users were mostly Iranians, but it's ...
6
votes
2answers
224 views
Geographic equivilent of RFC 3161 (X.509 PKI Time-stamp Protocol)
First time poster here, hope to be around more often.
I'm in need of a cryptographically secure 'stamping' system that allows not only time but also location to be attached to data, while still ...
6
votes
2answers
205 views
Is ECDSA breakable by quantum computers?
Is ECDSA secure from quantum computers? Will quantum computers be able to calculate it's private keys from the knowledge of the public key once there are working quantum computers?
6
votes
3answers
315 views
Why are CA's signing keys available on the internet
I am not very knowledgeable about CA certificates, but I thought these things mainly said
"The public key for bank X is Y, and this is verified by CA Z".
Once you've bought this certificate, there is ...
6
votes
2answers
372 views
security of PKI, Certificates, certificate authorities, forward secrecy
I want to understand how certificates add to the security of information exchange.
Suppose i have a encrypted bidirectional connection between Alice and Bob, using a public key/private key pair. As ...
6
votes
3answers
923 views
Certificate chain
For my computer to verify the identity of a certain certificate should it have all the certificates up to the root certificate?
6
votes
3answers
671 views
Safe implementation of sharing encryption secrets (username, password) in the cloud
I'm building a multi-tenant (cloud) environment that needs to push out (or make available for download) configuration files for agents (background services) that receive this information. One of the ...
6
votes
3answers
175 views
What risks would exist in transmitting an encrypted PKCS12 via Https
I have a scenario in which I would like to automate the deployment of client certificates generated by an issuer I control. The approach I am considering is given below, and I would appreciate ...
