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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7
votes
2answers
114 views

Verifying cryptographically signed files when the key has been revoked

This is mostly a question out of idle curiousity. If I use my private key to sign a file today, forming a signature, and distribute that signature with the document to someone they can then use my ...
4
votes
1answer
1k views

Encrypting/decrypting our license key

We need to provide a license key to customers for our application. The actual license is XML but we need to encrypt it and then in our program decrypt it. I think it is the following, but am asking to ...
0
votes
1answer
51 views

Authenticating a user by verifying a signature

Background I'm setting up an API which will be used primarily over HTTPS (only calls not needing any security what so ever is available over HTTP). Some aspects of it need to be accessed only by ...
59
votes
3answers
5k views

Why aren't IMSI catchers rendered ineffective by standard MITM defenses?

There's been a lot of reporting in the past few years about law enforcement agencies using IMSI catchers (also known as Stingrays after a popular brand of them) to intercept cellular communications. ...
3
votes
4answers
6k views

When should I use symmetric encryption instead of RSA?

I'm currently using GPG RSA keys to encrypt binary files. Many people recommend using symmetric keys to encrypt large files, and then encrypt the symmetric key with a public key. At what file size ...
6
votes
5answers
814 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, ...
3
votes
1answer
87 views

How can I enforce that an SSH private key has a passphrase?

My company is serious about security and willing to move to SSH key-pairs. Users can generate their SSH key pairs independently and I worry if they set a pass-phrase. Can I enforce this? Does signing ...
3
votes
2answers
148 views

Can a CN-only certificate bypass a name constraint if the CA goes rogue?

I am trying to cross-certify an internal issuer certificate, adding a name constraint for our domain. However, it seems that an attacker could bypass this protection by putting the desired host name ...
22
votes
7answers
3k views

Is there such a thing as public key steganography

One of the drawbacks of traditional steganography is that both parties need to exchange a secret key. Encryption had this problem too but circumvented this with public key cryptography. Are there ...
11
votes
3answers
466 views

How will SHA1 deprecation affect internal CA's?

I am hearing that the SHA1 Deprecation notices from MS/CHROME only apply to certs that are a part of a public trusted root program. This makes one believe that IE will have new logic built in to allow ...
7
votes
2answers
10k views

Certificate Chain checking

I have a very specific question. A client verifies a server by taking the certificate and checking specific values and that the digital signature of the intermediate CA is correct (according to the ...
1
vote
1answer
83 views

ECDSA implicit certificate using OpenSSL

I am trying to generate implicit ECDSA certificate only for signing and verification using OpenSSL. I tried google but I am getting many research papers. I understood that A messages need to be signed ...
0
votes
1answer
155 views

CSR with only public key with openssl

So I have been doing my research and haven't found anything specific enough to my problem. As the question title states, I want to make a CSR with only the public key. What I have been able to do is ...
0
votes
2answers
134 views

How In-House Certificate Authority works (e.g. EJBCA)

I have a simple (dumb?) question with respect to EJBCA. I have been exploring how In-house CAs work and issue certificates. However, I am not able to understand who will be trusted on the top level in ...
5
votes
2answers
155 views

Why is weakness of SHA-1 considered a threat to TLS security

If I understand correctly the role that a hashing algorithm (e.g. SHA-1) plays in TLS certificates is as follows: The hashing function is applied to a subject's public key. The CA then uses their ...
1
vote
2answers
58 views

Client verification with PKCS#7

When a client sends you a pkcs#7 file to communicate with you, Is this because the file has their public key(certificate) and their chain and to avoid the confusion on your side what needs to be there ...
3
votes
1answer
162 views

Understanding how does certificate validation work

I'm using Wireshark for better understanding how is a SSL connection established. I captured the traffic of visiting three pages: reddit, facebook and this one. All HTTPS of course. Reddit: after the ...
2
votes
0answers
29 views

Finding the EMSA-PKCS1-v1_5 DigestAlgorithm field in the x509 certificate

From the RFC - https://www.ietf.org/rfc/rfc3447.txt A.2.4 RSASSA-PKCS1-v1_5 For each OID, the parameters field associated with this OID in a value of type AlgorithmIdentifier shall have a value ...
21
votes
1answer
16k views

4096 bit RSA encryption keys vs 2048

Where do 4096 bit RSA keys for SSL certs currently stand in terms of things like CA support, browser support, etc? In the overall scheme of things is the increased security worth the risk of 4096 bit ...
2
votes
2answers
138 views

Self-signed cert - how it works

I am new to SSL / digital certificates / signatures. What I know is that a digital signature must be verified/decrypted using the public key. So a cert that is signed by a CA must be verified/...
16
votes
4answers
30k views

Recommendations for a Certificate Management tool for Linux [closed]

A client is looking to roll out OpenVPN to all its mobile employees and will use certificates on both the server and all clients. This creates a new challenge to manage all these certificates and ...
4
votes
1answer
115 views

SSL/TLS: Policy Constraints vs. Basic Constraints

Could someone please explain the difference between Policy Constraints and Basic Constraints? It appears to me that they are either redundant, or two names for the same thing. I would love some ...
0
votes
1answer
25 views

SSL key exchange [duplicate]

As I understand, when I log on to a website via HTTPS, the public keys are shared in the beginning of the conversation. I have read around the internet is that if a MITM manages to read the entire ...
5
votes
3answers
845 views

Certificate Transparency

From what I read here, if the intermediate CA has been compromised, a fake cert can be issued and the privacy of the end-users could be compromised as well. In order to remediate this situation, ...
-5
votes
1answer
106 views

Mobile number tracking

Is there any way we can track our mobile when it is lost? I have done a google search on the same and found that we have websites which give us the details of where the SIM was purchased & ...
1
vote
2answers
1k views

Encrypt files on FTP server

I have a practical situation here, my company is a FTP server provider for some clients. The clients are sharing their files on our FTP server and have had no problem with access management and ...
2
votes
1answer
81 views

How do “certificates” hold “keys”? [duplicate]

I am new to the realm of security and keep hearing about "certificates" containing "keys". But no one has been able to actually explain to me what is actually meant by this. I assume that the ...
0
votes
1answer
33 views

What's the actual danger of public key spoofing?

I am reading an excellent beginner's cryptography tutorial, and on this page there is the following blurb: Public-key cryptosystems have one significant challenge − the user needs to trust that ...
0
votes
0answers
54 views
0
votes
0answers
62 views

DSS digital signing approach

Under the DSS approach to digital signing, what is the advantage of using two pairs of keys for each signature?
0
votes
3answers
153 views

Difficulty of breaking private key password

I was recently reading up on the practices of keybase.io and came across this blog post. In it, the author says: ...decrypting the above [encrypted private key] is arguably as difficult as ...
4
votes
1answer
113 views

Should my company change the internal Root CA hash method from SHA-1 to SHA-2?

My company have a Root Certificate Authority which is installed on a Windows Server 2003 and uses SHA-1 as hash method. We will migrate to Windows Server 2012. Checking the root certificates of my ...
1
vote
1answer
60 views

Why is it not recommend to use permanent validity of certificate for public key [duplicate]

As we know it is not recommended to provide permanent validity of certificate for public key. I don't know why. Could you give me some reasons ?
2
votes
3answers
2k views

Key Exchange using PKI

I'm new to the field of cryptography and trying out a sample program to understand PKI key exchange mechanism. I tried creating a self signed certificate using openssl openssl req -x509 -nodes -...
-5
votes
1answer
84 views

What happens if two parties have the same public key? [closed]

What would happen if I get a public key that someone else already has? Isn't the security very weak in that case?
11
votes
2answers
6k 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 ...
0
votes
1answer
219 views

BLS signature java implementation needed (if possible, along with some example code)

I need to sign a string with the shortest digest possible using regular certificate like X.509. As far as I understand, I will have to transform the string to the sequence of bytes, then sign. After ...
26
votes
4answers
39k 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 ...
1
vote
2answers
569 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, ...
10
votes
4answers
8k views

Managing and storing lots of SSH keys in the cloud

I have a pool of cloud servers (~50) that need to talk to many other remote cloud servers (~4000) using SSH. Each remote server has its own SSH key, so we need a place to store all of these remote ...
0
votes
2answers
46 views

How to avoid writing .pem while signing a csr?

I am using following command to sign a certificate, openssl ca \ -in client.csr \ -keyfile server.key \ -cert server.crt \ -outdir ./some_dir \ ...
8
votes
1answer
2k views

Has the leaked D-Link windows signing key been revoked?

Recently news broke as to D-Link mistakenly publishing a private code-signing key as part of an open source framework. The D-Link key was leaked in late February, and expired on September 3, it ...
0
votes
2answers
140 views

SSL digital certificate process - high level

I am a project manager and is touching on an IT project consisting of the usual 3 tier - web/client - middleware - database. In this case, I have an web server and needs to implement SSL ...
3
votes
2answers
64 views

Comparing allegedly identical OpenPGP keys published through different channels

tldr version: When I try to compare public keys that are supposed to be for the same entity the versions I get through different channels are NOT the same and the ones that I download as a file like ...
4
votes
1answer
53 views

Can I get SSL certificates for my OpenPGP key?

How can I use letsencrypt to get a signed public key for use with OpenPGP? So I can prove in court the key is mine etc., and not have to rely on the OpenPGP web of trust.
3
votes
2answers
128 views

A potential possibility of improvement of PKI for personal communications

In countries like Germany each citizen has an identity card that is issued by the registration authority. Since the identity of a citizen is, in a sense, created by that authority via assigning him ...
6
votes
2answers
330 views

Custom data in SSL certificate

I am looking for a way to add extra, custom data in a SSL server certificate issued by a standard CA. Is this possible? I want to get a SSL server certificate issued by a standard CA, so that it'll ...
4
votes
2answers
54 views

Extend hierarchical PKI

The figure below shows four simple hierarchical PKIs. A, R, H and N are trust anchors of their PKI. I am supposed to add exactly one certificate so that T trusts G, but not D. Furthermore R must ...
3
votes
1answer
76 views

Best practice to verify data against a CA

Let's say that I have signed my public key with a trusted CA and the CA provided my with a signed certificate, and I want any client applications to verify against this certificate. The general ...
1
vote
2answers
231 views

What if the Local Windows Cert Store is Compromised?

The diagram below illustrates chaining digital certificates up to a publicly trusted Root Certificate: I have been researching how trusted root authorities (such as GlobalSign or Verisign) are used ...