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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2answers
155 views

Does Convergence solve the problem of hacked CAs?

My question is about the Firefox AddOn Convergence. So my question is if it is possible for convergence to observe that a phishing-site which is verified by fake Certificate because a hacker of a CA ...
10
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2answers
735 views

PKI solution vendor selection

What would you look for in a (X.509-) PKI solution, and why would you look for that, given the following constraints: Available programming/sw-engineering know how is limited (ie, "OpenSSL with a ...
16
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5answers
1k views

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
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2answers
55 views

Generic term for certificates and keys

Is there a generic term to designate both public and private keys, certificates and maybe even passwords?
2
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0answers
79 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 ...
16
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9answers
4k 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
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1answer
258 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
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2answers
706 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
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2answers
208 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
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1answer
197 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
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3answers
299 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 ...
29
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3answers
3k 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
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2answers
232 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. ...
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1answer
412 views

Determine private key size using public certificate [duplicate]

I have a public certificate in a PEM (.pem) file -----BEGIN CERTIFICATE----- MIICsjCCAZqgAwIBAgIJAMA1YIQ2JLXDMA0GCSqGSIb3DQEBBQUAMBExDzANBgNV ... 29V/R9RZOoSBHDzGPL84wm4qojMuwQ== ...
25
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4answers
11k 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 ...
44
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8answers
11k 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
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1answer
207 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
436 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 ...
0
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1answer
39 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 ...
5
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4answers
340 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 ...
15
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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 ...
7
votes
10answers
6k 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 ...
2
votes
1answer
276 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 ...
3
votes
1answer
151 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 ...
4
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4answers
279 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
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1answer
145 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 ...
77
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
92 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
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1answer
59 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 ...
9
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2answers
9k 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
93 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
25 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 ...
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2answers
105 views

Subordinate Certification Authorities and managed certificates

How many different certificates can a subordinate certification authority manage? Please, supply me also some reference. Thanks
1
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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?
5
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1answer
416 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
240 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 ...
1
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1answer
399 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
364 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, ...
15
votes
5answers
10k 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 ...
36
votes
4answers
27k 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?
16
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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 ...
0
votes
1answer
220 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 ...
4
votes
2answers
344 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 ...
0
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1answer
60 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 ...
2
votes
1answer
57 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 ...
2
votes
5answers
526 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 ...
25
votes
1answer
46k views

Can a CSR be created in OpenSSL with SHA2?

Can a CSR be created in OpenSSL with SHA2? If so, what would the command be and what does this tell the CA, if anything? If you could create a CSR using SHA2 would it "tell" the signing CA to use it ...
3
votes
2answers
110 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 ...
18
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4answers
14k 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 ...
3
votes
2answers
106 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 ...