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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28
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5answers
13k 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 ...
0
votes
0answers
6 views

Where partially homomorphic encryption schemes like BGN are used?

Schemes like Boneh, Goh, and Nissim are interesting, because of support of polynomially many additions and one multiplication. The algorithms are indeed simple https://eprint.iacr.org/2010/182.pdf ...
0
votes
1answer
18 views

Firefox refuses to use X509 certificate, complaining “Cound not verify this certificate for unknown reasons”

I stumbled upon this question and answer. I have the same problem as the OP, and am sorry to report that the proposed answer does not resolve it. Certificate in question has been verified by OpenSSL-1....
0
votes
1answer
331 views

How to get “Policy: X509v3 Any Policy” in a certificate generated with 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: ...
1
vote
1answer
20 views

does openssh support authentication using public key fingerprints?

Cisco have two ways of enabling public key authentication: using the public key and using the public key hash. ip ssh pubkey-chain username <user> key-string <public key> OR ...
0
votes
1answer
45 views

Are there any risks in wrapping asymmetric encryption in symmetric?

The web app I am developing should be end-to-end-encrypted, but for slightly better user experience, I do not want the user to enter private keys into the client. Instead I am planning to store the ...
1
vote
0answers
38 views

Certificate based Access Control for Pub Sub messaging

I'm extending an existing p2p/master Pub Sub framework to support additional security measures, via over the wire encryption and topic based access control. I'd like to use the x.509 certificates that ...
2
votes
2answers
43 views

CA Certificate Lifecycle

I'm planning to implement a new PKI with 2 tiers of CAs. I'll have end entity certificates with a lifetime of up to 5 years. This means my Issuing CA should be valid for 10 years, in order to be able ...
1
vote
1answer
80 views

What's the minimal way of sharing your public PGP key in email signature?

What's the minimal (not the entire public key) and secure enough way of sharing your PGP key in an email signature?
9
votes
1answer
110 views

What LDAP schema is recommended for PKI?

In my research, I found some RFCs that have not been updated in over a decade, e.g draft-ietf-pkix-ldap-crl-schema-01. I also explored several public directories used in PKI (e.g. x500.bund.de) and ...
8
votes
1answer
4k views

SSL certificates and cipher suites correspondence

I have been learning about the SSL/TLS protocol (from https://tools.ietf.org/html/rfc5246) and have a few conceptual questions about the protocol. The client and server exchange "hello" messages ...
0
votes
1answer
47 views

X509 / SSL certificates in practise

After learning the theory behind cryptography I'm having quite some problems understanding how SSL or X509 certificates works in practise and I simply cannot find useful information in the internet. ...
1
vote
1answer
94 views

Can Passpoint X.509 certificates be used to MITM SSL connections on Passpoint networks?

Passpoint/Hotspot 2.0 public networks like LinkNYC require users to install X.509 certificates, for EAP authentication. Can these certificates be used by the provider to execute man-in-the middle ...
0
votes
1answer
43 views

How to configure SSH public key per user?

I have an OpenSSH server running and different users can log into it with different privileges. I know you can enable public key authentication and place all the allowed public keys in the ...
8
votes
1answer
319 views

How can WhatsApp recover messages sent to a damaged phone?

My mom has an Android phone that fell in the water for a couple of seconds, around 16:30. She managed to disassemble the phone and turn it off. We both share a group that is end-to-end encrypted (all ...
6
votes
1answer
83 views

Is there a way to know if a server is using ssh public key or password?

I am wondering is there a way for an attacker through finger printing to find out whether a server is using public-key versus password authentication method for establishing an SSH connection?
6
votes
1answer
117 views

Manually walking through the signature validation of a certificate

Since I am not too familiar with the Web of Trust and Public Key-Infrastructure I decided to learn about it by following the signing chain of a X.509 certificate issued to CN=*wikipedia.org (Serial ...
3
votes
1answer
45 views

Verifying SSH fingerprint of a public server

I have read somewhere that servers which have SSH access for users in the public can have their public key posted publicly (e.g., on a website), so that people who access such a server using SSH can ...
2
votes
1answer
1k views

OAuth and public keys

I get the basic OAuth and PKI flow and the different actors involved but I'm still unsure how public/private keys play a role. When a client identifies itself upon registration with a certified ...
9
votes
2answers
528 views

Why SSL uses a third party (certificate authority) yet SSH does not [duplicate]

SSL operations require the use of a trusted third party -- the certificate authority to verify a public key presented by a server to a client. SSH on the other hand relies on the client having the ...
1
vote
1answer
117 views

PKI management with easy-rsa

I recently setup an OpenVPN server with easy-rsa and have questions about certificate revocation: In the event that someone's private key gets compromised and I have to revoke the certificate with ...
0
votes
1answer
49 views

Whatsapp encryption: are the public keys requested from the server every new message or only at session setup?

I was reading trough Whatsapp white paper (and all related questions here) and couldn´f find an answer to this question: are the public keys for the recipient requested by the sender from Whatsapp ...
0
votes
1answer
32 views

PKCS #11 with the TPM

I try to understand PKCS #11 Standard. I found this link. There is this picture. So this picture is in the case of the Trusted Platform Module(TPM). We have the SRK which encrypts with the Private ...
4
votes
1answer
124 views

Centralized key management for IOS and Android Code Signing

What is the best way for an enterprise to manage code signing certificates? The default seems to be that Apple and Android keys get stored by each developer on their machines. I see systems like ...
2
votes
1answer
286 views

How CERT.rsa is interrelated with PackageInfo signatures

I am a newbie in security and cryptography, but I am developing Android applications and now wanna to dive deeper into the Android security mechanisms. I am trying to understand how CERT.rsa (as I ...
0
votes
0answers
45 views

TOTP: Storing symmetrical secrets

I'm in the process of researching 2fa methods for a cloud connected physical access control system. There is very little margin for error in this space. Is it just me or does TOTP for two factor auth ...
2
votes
1answer
99 views

Generating shared secret key using existing receivers public key and senders private key

I have the public key of the receiver, and the private key of the sender. I want to generate a new key by using the receivers public key and senders private key (also known as the signing key) to ...
1
vote
2answers
115 views

sharing private key sTunnel

All of the sTunnel guides and implementations at work do the same thing, they say once the private key and the public cert are created on the server, you need to cat them together and then share with ...
0
votes
0answers
35 views

Migrate a key with a TPM

I try to understand how TPM devices handle the migration of a key. So I found this link: shazkhan.files.wordpress.com (page 4-5) I think I have understood how the rewrap scheme functions, and now I ...
0
votes
0answers
20 views

Client blocking based on PKI

I've got following scenario: Own PKI in a private network Some webservers in the private network, accessed by load balancing via proxy from the web Now I'd like to block all clients their ...
0
votes
1answer
168 views

Is this company's claim to have solved MITM attacks true?

The Daily Mail reported in Dec 2014 about a company that claimed to have solved the MITM attack. Can someone explain how this is possible or what the difference is from TLS?
1
vote
1answer
43 views

Private key and wildcard certificates

I'm trying to understand the implications of private key leakage (due to Heartbleed) from a website that uses a wildcard certificate. If an organization has a wildcard certificate (valid for *.domain....
3
votes
3answers
82 views

Why does PKI use a hash function?

I'll preface my question with my understanding of PKI in case I have any misconception. Owner of domain D generates a public-private key pair (d,e), and constructs a certificate c consisting of (d, ...
2
votes
2answers
784 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: ...
5
votes
4answers
9k views

Extracting the PGP keyid from the public key file

Is there a way via an CLI tool or some kind of API to extract the PGP key ID from the PGP public key block? I found the hexa value of the key in the binary file, but I guess the position is based on ...
1
vote
1answer
294 views

How to make sure that the public key has not been tampered with during transit?

I understand how public key infrastructure works. There is a private and public key, and someone may use the public key to encrypt data that can only be decrypted with the private key. However ...
0
votes
0answers
32 views

Use MDC to provide origin authentication for public key encryption?

Why can't we use an manipultation detection code (MDC) to provide origin authentication when using public-key encryption?
2
votes
1answer
47 views

AuthorizedKeysCommand of sshd_config getting called twice

AuthorizedKeysCommand paramter present in the file /etc/ssh/sshd_config. The bash script which i called using this command is getting called twice. The config file is as follows #RSAAuthentication ...
8
votes
2answers
11k views

What damage could be done if a malicious certificate had an identical “Subject Key Identifier”?

I'm looking at the the Subject Key Identifier attribute of a CA certificate and am trying to understand the role it plays in validation and infer how validating client software could get it wrong. ...
1
vote
2answers
103 views

Can I move my private-key to a better token?

I recently purchased a personal signing certificate from GlobalSign - it wasn't cheap either. It arrived yesterday. GlobalSign gave me a "blank" USB security token device - a SafeNet eToken 5100. ...
0
votes
2answers
42 views

Does PKI signature verification require secure distribution of public keys?

I'm looking at a software project where the GPG public keys of the maintainers are found on a website using HTTP. According to the GNU Privacy Handbook, "The signature is verified using the ...
0
votes
1answer
31 views

Does password protected git public key protect my repository?

When generating my public key for GIT access, I decided to set up a password for it. My push procedure looks like this now: Enter passphrase for key '/c/Users/USERNAME/.ssh/id_rsa': Counting objects: ...
4
votes
1answer
140 views

Safely store passwords in specific scenario

I have a specific network environment. Its a DTN(Delay Tolerant Network) network without continous connectivity, situated on the sea, where nodes are ships. There is also a server that is a part of ...
1
vote
2answers
36 views

Why there is time period of key pairs in public key cryptography?

In Public Key Infrastructure, every key pair is associated with its life time. I don't understand why we have a life time when we have functionality such as certificate revocation list(crl) which ...
1
vote
1answer
34 views

Multi-User-Server Public-Key-Based Authentication

So, lets say we have Alice, John, Peter and Bob. Alice, John and Bob all know Peter's public key and trust Peter. Alice wants to connect to Bob's server, so she presents her public key, which was ...
0
votes
1answer
139 views

Code signing certificate validation by Java

Despite several web search, I can’t find an accurate explanation on code signing certificate validation by Java. I am wondering if the code signing certificate (the “final cert”) must already be in ...
7
votes
4answers
31k views

SSL Client Certificate authentication

Is it possible to make a program which uses client certificate authentication with only public and private key (I have not generated any certificate, I have only public and private key). Simply, I ...
2
votes
1answer
114 views

What is the difference between a digital signature and whole message encryption?

I am newbie in information security I am trying to understand the difference between a digital signature and encryption of a message. Lets consider simple example of email message. I understand how ...
1
vote
1answer
32 views

Is there a secure method of distributing keys to network-booted diskless nodes?

I have a bit of an 'initial trust' issue. We are using CoreOS to run Kubernetes, and secure both the etcd API and the Kubernetes API servers using client certificates. We are using iPXE to boot ...
-1
votes
1answer
51 views

Same certificate but different private keys on different servers. Does this work?

We have a SAN cert that is used on multiple servers. Is it possible to have the cert re-keyed and only use the new private key on a particular server while keeping all of our other servers using the ...