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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1answer
7 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
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1answer
15 views

Any Value in an AIA Extension in a Certificate Issued by 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 ...
-6
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0answers
26 views

Public and private key geerating in C Code source ? [on hold]

I'm looking to a public and private pair key with C ( like this one in the link below ) , is there any one have the source code of it ? any help would be appreciated ! Thank you . Create RSA public, ...
0
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2answers
58 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, ...
37
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8answers
6k 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 ...
3
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1answer
23 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 ...
2
votes
1answer
95 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 ...
5
votes
1answer
55 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: ...
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 ...
2
votes
1answer
64 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
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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 ...
3
votes
4answers
93 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 ...
3
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1answer
95 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
17 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 ...
0
votes
1answer
122 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 ...
0
votes
1answer
86 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 ...
7
votes
1answer
86 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, ...
0
votes
1answer
93 views

Begin of Certificate/ End of Certificate dash “-----”

What significance does the dash "-" holds along with the line -----BEGIN CERTIFICATE----- or -----END CERTIFICATE-----. I checked multiple docs and linked RFC's as well but could not find the ...
16
votes
4answers
3k views

Is it dangerous to publicly share ciphertext?

Alice wants to share a message with Bob, but Alice and Bob can never be in the same place at the same time. We can assume they both know each others public keys (or agreed on a shared key, if that ...
1
vote
1answer
36 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 ...
2
votes
1answer
35 views

Https certificate change effects on established secure channels

I've a question regarding https certificate changes. Does anyone know any side-effects to changing the certificate, one signed with RSASHA1 to one signed with RSASHA256 for ex, while users already ...
0
votes
1answer
40 views

CSR signing follow up question

This is a follow up question , after getting a signed certificate from one CA. researched a lot , but no luck. After getting the CA reply, While downloading the certificate, it popped up saying ...
3
votes
2answers
76 views

CSR Signing simulation

Tried a lot get my test csr signed from root CA(trial versions option), somehow i am not getting it dues to some of their internal check. Few questions that cropped up Can i somehow signed that ...
9
votes
1answer
240 views

I want trusted SMIME certificates for 3rd parties. Is this a reasonable configuration?

I want to send out SMIME certificates with my emails, and want to deploy the following PKI Root01 (All EKU, All Constrants, No Restrictions) PolicyInt01 (Internal applications, not trusted by 3rd ...
2
votes
2answers
50 views

Certificate pinning and the key distribution problem

I (think I) understand the concept of certificate pinning. However, I'm wondering if, in the worst-case scenario: is certificate pinning any more secure than the hierarchical trust model it is built ...
3
votes
1answer
54 views

Ability to determine which PGP public keys a message has been encrypted for?

Is it possible to determine, given a PGP message that you can already decrypt, to determine which other PGP keys that message has also been encrypted for?
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2answers
53 views

Can revoked certificates be “lost” if the base CRL is updated before expiration?

Assumption Suppose I have a CA that issues a base and a Freshest CRL. I also understand the Freshest CRL to be a Delta of revoked certs in the base. I also understand that clients should pull the ...
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0answers
21 views

What is the minimum acceptable time for “Freshest CRL” to be updated?

I'm working with MSFT CA, and not sure if this behavior is the same across all CAs, but when I run certutil -CRL, the base revocation cert is updated weekly, and the Freshest CRL (the differential) ...
1
vote
1answer
64 views

P12 private key vs private key file : what is more secure?

The question is a bit tricky because they don't have the same purpose but : Do both kind of file face the same security issue concerning private key protection : password strenght ? (PBKDF2 as both ...
4
votes
2answers
181 views

Explicitly prohibit an intermediate CA certificate on OpenSSL

How do you explicitly not trust a particular certificate (especially, CA certificate) for OpenSSL? On NSS-based applications, one can install the cert with trustarg p: prohibited (explicitly ...
1
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0answers
20 views

What are some scenarios I would use MSFT Certificate Enrollment Web Services?

The Certificate Enrollment Policy Web Service and the Certificate Enrollment Web Service are made for non domain connected machines to retrieve certificates of various kinds. When setting this up, I ...
0
votes
0answers
28 views

Distribution of key by server

I have read that in asymmetric cryptography, a system admin can generate key pairs on the server. After that, the users will be given the generated key pairs and this is an efficient way of doing this ...
1
vote
5answers
103 views

multiple private keys for single public key

I am currently working in security in mobile ad-hoc networks I have several clusters, and I want from the cluster head to send some data encrypted with its public key ,to the cluster members. I assume ...
3
votes
1answer
91 views

Clarification needed on CSR signing process

There doesn't seem to be a lot of in-depth information on the certificate signing process other than: Key Management Interoperability Protocol Usage Guide Version 1.2 (PDF) RFC 2986 - PKCS #10: ...
2
votes
1answer
56 views

How do Client-specific keys and Certificates work?

I have clients that communicates with my server. Clients sends it unique id (guid) to server with its request over a secure https channel. Also to increase security I use my own private-public key ...
0
votes
1answer
40 views

public key formats [closed]

I have the following PEM format public key: -----BEGIN PUBLIC KEY----- MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDguwHaldTclMAFg1BQ45Q8DPIc ...
2
votes
2answers
65 views

Does an alternative approach to PKI technology exist?

Currently all of the network is using PKI standards and we are facing many problems. I don't mean every time and if new technologies arise we will also have to face the same, but for my curiosity. ...
1
vote
1answer
134 views

How do PGP keyservers synchronize the keys?

I want to know technical details about how public PGP keyservers synchronize the keys. If I send my key to one keyserver, how exactly does it "travel" to all the other ones? Who sends it to who and ...
4
votes
2answers
90 views

How should I document my Public Key Infrastructure?

I'm preparing to document a 3 tier PKI (with multiple second level policy CAs) and want to create a document that is useful, technical, and not too overwhelming to the non-PKI expert. I suppose the ...
0
votes
1answer
62 views

What is the purpose of the CA-BUNDLE on a webserver?

So I purchase a certificate from DigiCert. The process goes like this: Generate private key and CSR on web server. Submit CSR to DigiCert. Get a signed certificate back as well as their root ...
1
vote
1answer
59 views

Why should I have my GPG key expire? [duplicate]

When creating a key pair using gpg it asks me for an expiration date: $ gpg --gen-key Please specify how long the key should be valid. 0 = key does not expire <n> = key expires ...
1
vote
3answers
62 views

Secure tunnel set up in an office environment

Suppose I am a rogue employee and I want to syphon some sensitive data out of the office and I only have office internet access for this. My office internet access needs to go through a proxy server, ...
0
votes
2answers
143 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 ...
2
votes
2answers
85 views

How can I create my own public certificate using openssl?

I have a public key/private key pair i generated using two primes p and q. I now need to use openssl to sign and create the certificate. I heard req utility and wrote this from the man pages. openssl ...
0
votes
0answers
13 views

why DH is unbreakable and what are the facts that leads to strong DH? [duplicate]

I am new to DH and learned the basic about DH working and suspecting it can be breakable by normal MIM , then how we can use DH in plain http for sharing secret. correct me if i am wrong.
0
votes
1answer
32 views

PKCS#12 File - security impacts when imported in Web Browser or Windows Store?

When a PKCS12 file is imported into a Web browser or Windows store the user is prompted for private key password. How does the browser or operating system manage this password? Is it secure?
4
votes
1answer
35 views

Mail Signing Certificate – What are the impacts when revocated?

Suppose I open a signed mail on 1st January 2000, signature is OK. What about this two cases : 1) If next CRL is to be published one week later, I found it strange that it is “probably” valid until ...
12
votes
1answer
783 views

Relationship between RSA, Diffie-Hellman Key Exchange, PKI and X.509?

I am getting confused with RSA, Diffie-Hellman Key Exchange, PKI and X.509v3. I took a look of RSA's mathematics algorithm, it seems like a encryption algorithm, right? Generating public key and ...
0
votes
1answer
183 views

Sign PKCS#7 and verify PKCS#7 signature with OpenSSL

If someone have to transfer X.509 certificates in a single bundle, usually, it is recommended to pack them into PKCS#7. And content of PKCS#7 can be signed. OpenSSL allows to pack certificates into ...
4
votes
2answers
106 views

Verify digital signature without key public key in signature

When receiving emails, I sometimes see the following: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I found an integer overflow in PHP, in the conversation of dates to "Julian Day Count" function. ...