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 ...

learn more… | top users | synonyms (1)

12
votes
5answers
635 views
+500

Creating my own CA for an intranet

I need to create my own CA for an intranet and unfortunately it seems there's no good answer about this on Security.SE. There are many resources online about this, but all of them are different and ...
0
votes
2answers
42 views

Generic term for certificates and keys

Is there a generic term to designate both public and private keys, certificates and maybe even passwords?
3
votes
2answers
73 views

Can the intended recipient be derived from a public-key encrypted ciphertext?

Assuming you have a list of possible recipients' public keys, and a ciphertext encrypted with one of those public keys, would it be possible to determine which public key?
2
votes
0answers
13 views

CMS/PKCS#7: specifying signatureAlgorithm with digest?

I'm confused about algorithm selection for Cryptographic Message Syntax (a.k.a. CMS, PKCS#7) signed objects (RFC5652 Section 5.1). The SignerInfo structure (RFC5652 Section 5.3) has two separate ...
0
votes
2answers
195 views

P12 - Extract public part (certificate) without knowing the p12 password

I would like to extract the public part of a revoked P12 which doesn't belong to me. I can't open it with KeyStore Explorer because I am prompted for the password, is it possible with OpenSSL ? The ...
15
votes
9answers
546 views

How does SSL/TLS PKI work?

We have lots of questions that address portions of SSL/TLS as it relates to PKI, but none of them seem to bring everything together. A canonical answer that we can point people to I think would be ...
1
vote
1answer
209 views

Chat encryption system avoiding protocol sniffing and then key+decryption replay?

I'm working on a chat system and I want to add it some kind of security (not just HTTPS with SSL since I've read it can be sniffed and decrypted with a few tools). Now, my knowledge in cryptography is ...
1
vote
2answers
491 views

How do I verify, parse and process the results of the HTML5 keygen tag?

I'm investigating the HTML5 attribute Keygen and discovered that it sends this data on a Form POST to the server. Here is an example POST: ...
7
votes
2answers
126 views

Can symmetric key cryptography provide identification?

I understand that PKI uses digital certificates to link a public key to an entity, but is there anything similar for symmetric cryptography. If, theoretically, PKI didn't exist, how do you know you ...
3
votes
1answer
135 views

HSM maintenance

I have a HSM that is an asset within a information security management system and the help desk team tells me that the device is displaying a critical failure alert. So my questions are: Must I ...
1
vote
3answers
36 views

What type of hashing method is used for the private key to encrypt for signing messages?

To use RSA for signing, Alice takes a hash of the message, encrypts the hash using her own private key, and appends the result (this is the signature) to the message. Eve can of course still ...
27
votes
3answers
2k 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 ...
0
votes
1answer
121 views

Is it dangerous to use the same key (RSA) for both encryption (PGP) and authentication (SSH)?

Alice wants to send an encrypted message to Bob, but she also wants to connect to Carol's server. Are there any dangers associated with using the same RSA key for both PGP and SSH (other than a lack ...
-1
votes
0answers
32 views

InvalidKeyException using ECPublicKey [migrated]

I'm getting the following exception when i try to encrypt a byte array with a EC public key : java.security.InvalidKeyException: No installed provider supports this key: ...
1
vote
1answer
2k views

Generating ECDSA certificate and private key in one step

Similar to how it can be easily done for RSA: openssl req -x509 -nodes -newkey rsa:2048 -rand /dev/urandom -keyout example.key -out example.crt -days 365 I'd like to generate a ECDSA cert/key in ...
0
votes
2answers
30 views

Hierarchical PKI trust model

Suppose we have the hierarchical trust model as seen below. Alice will trust Doris' public key iff there is a Certifcation Path from her to Doris. Alice thus pocesses a valid certificate of A. ...
1
vote
1answer
32 views

Determine private key size using public certificate [duplicate]

I have a public certificate in a PEM (.pem) file -----BEGIN CERTIFICATE----- MIICsjCCAZqgAwIBAgIJAMA1YIQ2JLXDMA0GCSqGSIb3DQEBBQUAMBExDzANBgNV ... 29V/R9RZOoSBHDzGPL84wm4qojMuwQ== ...
21
votes
4answers
8k 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 ...
41
votes
8answers
7k views

Why can't you work backwards with public key to decrypt a message?

As the title suggests, I am curious to know why you can't work backwards using a message, public key and encrypted message to work out how to decrypt the message! I don't understand how a message can ...
2
votes
1answer
62 views

Can I place a private key on a sim card?

After google searching about this idea and yielding very little in results I've come to resort to stack exchange: Is it possible to place a private key on a sim card? Is it possible for a smart ...
6
votes
1answer
204 views

Should I install my subordinate Certificate Authority on the domain controller? Why?

I must install a PKI in my organization. I work in a windows environment. I already set an offline CA. I must now install a subordinate CA. I have the choice between installing the subordinate CA on a ...
3
votes
4answers
381 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, ...
0
votes
1answer
25 views

Asymmetric Encryption Digital Signatures

Here is the paragraph I can't quite get my head around. Alice sends a message to Bob and wants him to be sure the message has come from her. • She publishes her public key. • She computes ...
4
votes
4answers
159 views

If the public key can't be used for decrypting something encrypted by the private key, then how do digital signatures work?

I'm learning asymmetric encryption in the use case of ssl/tls protocol. I can understand that the public key (like a padlock) can encrypt (lock) something and only the private key can decrypt ...
14
votes
9answers
3k views

Why is a public key called a key - isn't it a lock? [closed]

I'm totally confused by the public key and private key terms. From my understanding, the "public key" is used for encrypting data, it's more like a lock which can lock something in and only the ...
1
vote
1answer
56 views

PKI/Why does Microsoft require my cert before encrypting an email?

Microsoft doesn't allow sending public-key encrypted messages using Outlook 2003-2012 on Windows 7-8x environments without first creating your own Digital ID or private key for signing. Per ...
7
votes
10answers
4k 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 ...
12
votes
3answers
3k views

Why do PGP master keys only have a single subkey, and tie certification with signing by default?

After learning more about PGP subkeys and how to split apart the roles of (S)igning, (E)ncryption, (A)uthentication and (C)ertification, I discovered that in most cases(?) a default master key has a ...
0
votes
1answer
45 views

Is there any use in an AIA Extension in a Certificate directly issued by a Root CA?

While most documentation I've read states that there is no requirement to have the AIA extension in a self-signed Root certificate (logical enough), I can't find anything that tells me not to do so in ...
1
vote
1answer
41 views

SSH: What's the difference or interplay between /etc/ssh/[host files] and ~/.ssh/[public key]

I'm new to SSH after a decade of dabbling with Ubuntu and other Linux builds. Today I successfully setup SSH, but I had a few hangups and headaches along the way. Although the system is now running ...
0
votes
2answers
85 views

Understanding Certificate Pinning [duplicate]

I am attempting to implement certificate pinning across a suite of mobile apps. I have been reading a lot about the different strategies (pinning to the CA/intermediate, pinning to a leaf cert, ...
3
votes
1answer
41 views

PGP Owner Trust Field & Signature Trust Field Distinction

I'm reading Cryptography and Network Security Principles and Practices (5th ed, p584) and reading about PGP keyrings, I'm a little confused about the differences between the owner trust field and the ...
3
votes
4answers
109 views

Should name constraints be present on a subordinate CA issued to an organization?

I was looking at Google's Internet Authority G2. Its a subordinate CA (critical, CA:TRUE, pathlen:0) certified by GeoTrust. The dump is below. Presumably, GeoTrust certified that CA for Google so ...
2
votes
1answer
106 views

Security Structure of an API

I've been developing a web application and APIs for 8 months. I implemented OAuth 2.0 client credentials for authentication. And now I have to implement TLS to my APIs. I've been dealing with SSL/TLS ...
75
votes
2answers
5k views

How are private keys kept private?

This may sound like a stupid question but seriously how are private keys kept private? If you're someone like Google you have some huge number of servers to which the public can establish secure ...
5
votes
1answer
60 views

Relationship between HTTPS and SSH Public Keys

I can use my private key to generate a public key for use with ssh. I can use the same private key to generate a CSR, to generate a CLIENT certificate for HTTPS. Specifically, my SSH public key is: ...
1
vote
1answer
37 views

What bits of data is revoked in a CRL? Is it the hash(CSR) or hash(CSR + PKI signature)

My understanding is that a CSR contains the public key from the client, and the response is a signed version of that CSR, with certain attributes (EKU, expiration) and other attributes the CA decides ...
7
votes
2answers
6k views

How is an X509 certificate signer verified?

Lets say I create a self-signed X509 certificate A and use it to issue certificate B. I put certificate A in my trusted root authorities so that all certificates signed by it are accepted. My question ...
2
votes
1answer
66 views

Use the server's key to digitally sign the HTML content it delivered?

Is there any way to prove that a HTML page was delivered to my browser, and not modified in any way, after it was delivered over TLS? I need to prove integrity, and authenticity of the sender, ...
0
votes
0answers
22 views

SSL Handshakes and authentication? [duplicate]

I was just wondering if someone could explain the complete process of SSL handshake with certificates, public - private keys and MAC exchange. And in which cases does the Certificate warnings arise ...
0
votes
2answers
73 views

Subordinate Certification Authorities and managed certificates

How many different certificates can a subordinate certification authority manage? Please, supply me also some reference. Thanks
0
votes
2answers
2k views

How to test for OCSP?

I have to test OCSP feature on a SSL server. Since it is a pretty standard feature now, I was looking around for tips on test plans/setting up OCSP responder etc?
473
votes
3answers
230k views

How does SSL/TLS 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 ...
3
votes
1answer
123 views

Asymmetric / end to end encryption for web messaging app

Background I'm trying to design a secure and sustainable web app for messaging. The purpose is to learn how to create secure web application. The application is suppose to be written in Javascript ...
2
votes
0answers
33 views

Mitigating the risk of disabling EPA on ADFS

I'm currently investigating the deployment of an Active Directory Federation Services (ADFS) server for providing Single Sign-on for various services. By default, ADFS enables support for Extended ...
82
votes
5answers
57k 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 ...
0
votes
1answer
131 views

Crypto Ransomware - How decryption is done when user accept to cooperate?

When you have been "hacked" and you accept to pay for decrypting your encrypted files, how the attacker do the job ? I understood that a symmetric key is used, itself encrypted by the attacker public ...
8
votes
1answer
120 views

RSA key generation: gpg vs openssh

When I generate RSA key for ssh (both server-side and client-side): dpkg-reconfigure openssh-server ssh-keygen the key generation is completed instantly. However, when I generate RSA key for gpg, ...
11
votes
5answers
7k views

SSH password vs. key authentication

I've usually been told that public key authentication is strongly preferred over password authentication for SSH. However our previous admin was against public keys and only issued passwords and took ...
29
votes
4answers
21k 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?