Questions tagged [public-key-infrastructure]

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 certificate authority (CA). There are three main categories of PKI: Web / SSL certs, corporate networks, and Government ID / ePassport.

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10
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1answer
2k 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 ...
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1answer
628 views

Trustworthiness of Let’s Encrypt and ZeroSSL within browsers and OS [duplicate]

With regard to Are there technical disadvantages in using free ssl certificates? it has been highlighted by some that StartSSL is not a trustworthy CA, and I was wondering if Let’s Encrypt is the same....
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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 ...
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1answer
935 views

3DES is used as symmetric or asymmetric encryption?

checked couple of online options which says 3DES is symmetric encryption(which means a single key is shared between two to encryption and decryption) but I have seen many EDI production system(AS2 ...
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1answer
82 views

How does blockchain client trust other nodes?

If we consider any blockchain based system (bitcoin, for example), how does initial trust setup works? When a new user wants to join blockchain network, how does the client know that it talks to ...
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1answer
74 views

Web of trust jeopardized because servers getting hacked?

I've read that a common way for servers to handle the SSL certificate is that the private key is not encrypted. Now, a many web servers are getting hacked each day. Assumed that the private key is ...
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2answers
153 views

Private Blockchain VS regular Public-key cryptography [closed]

Private Blockchain (permissioned) VS regular Public-key cryptography: What is the need and add-value of a private blockchain (permissioned) if one can use normal regular public-key cryptography?
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2answers
461 views

SHA-1 deprecation impact on personal PKI certificates

I understand that most commercial browsers will stop trusting websites with SHA-1 PKI certificates by Jan 2017 so it is critical for websites to update to SHA-2 by that time. My question is, is it ...
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3answers
460 views

What kind of IoT devices use certificates?

I have read that PKI certificates are the main way to provide security on IoT platforms. And the common enrollment protocols for certificates are: SCEP (Simple Certificate Enrollment Protocol) EST (...
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2answers
168 views

Usage of same certificate for client and server authentication

Let's assume I have a device that has both client and server applications running on it at the same time. The client application for example connects to a remote secure webserver (HTTPS) that requires ...
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1answer
161 views

Can Apple technically intercept iMessage messages

I'm basing this question off the iOS Security Guide. If I understand this correctly, when you enlist in iMessage, the private key stays on your device, while the public key is pushed to a directory ...
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0answers
171 views

Client authentication using certificates in M2M communication

We're planning to implement following scenario for a secure machine-to-machine (M2M) communication network. We have some gateways and a lot of secure sensors which should only be able to "speak" to ...
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Why CA certificate can't be spoofed? [duplicate]

I was trying to learn TLS in depth. Probably my understanding is wrong. This is what I understood: At the end of client handshake, the server will send the CA certificate to the client which contains ...
2
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1answer
104 views

How to single key decrypt pgp encrypted mails in a multi key/multi identitiy setup?

For pgp encryption I'd like to combine short expiry terms for public signing and email encryption with (convenient) long term decryption possibilities of my mailbox mails. I'm using several mail ...
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3answers
4k views

Where are private keys stored? [closed]

May sound like a silly question but where are private keys stored as part of Asymmetric Encryption? For example say I have a Web Server and I install a 3rd Party SSL certificate from a third party. ...
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1answer
51 views

Extra EKUs set in client certificate a security risk?

I have implemented a 2-tier Windows AD CS PKI. For 802.1x I'm using autoenroll to distribute computer certificates automatically to any domain joined computer. Currently I use a single computer ...
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3answers
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Why should my certificate signing request be signed by my private key?

Why should my certificate signing request be signed by my private key? Even if I obtain a bogus certificate out of someone else's public key, that is going to be useless, since in SSL the ...
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1answer
266 views

PKI: why is leaked CA certificate a threat?

According to the SSL/TLS threat model from ssllabs: https://www.ssllabs.com/downloads/SSL_Threat_Model.png Why is "Leaked CA Certificates" a threat? (In the "Trust (PKI)" branch) Isn't the purpose ...
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1answer
486 views

Which type of smart card supports certificates?

For an IT security demonstration I want to set up a small demo PKI including smart card authentication based on certificates generated by a Certificate Authority, using a class 3 pin pad reader. For ...
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1answer
60 views

Why is establishing trust in public key cryptography a harder problem than its computational costs?

In one of our exams for a non security course, the professor asked for one key problem for public key cryptography and explain why is it a hard problem. Several students claimed that the hard problem ...
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2answers
352 views

DRM using embedded private key

I've started learning about cryptography used for DRM solutions, and curious to know if this is a valid solution for a custom embedded system running purchased software assets. ECDSA public / private ...
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2answers
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Storage of certificates and keys in hardware security modules (Use-case TLS)

I am interested in the general security goals for public key cryptography and the different elements of it. Outline of the use-case: My use case is an embedded device, which will use TLS to establish ...
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1answer
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How do I detect if the public key in a digital certificate is modified?

I know how the basic process of digital certificate, but how do I detect if the public key in a digital certificate is modified?
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1answer
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Vendor Mutual SSL required on behalf of different organisations

I'm a software designer (former IT SysAdmin) trying to wrap my head around some authentication requirements in an API Specification document. Let's say government department (abc.gov) has created a ...
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1answer
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TLS- Concept of channel binding

TLS-Handshake is based on public-key cryptography for symmetric key exchange, pki for server-authentication and assume the user authentication is realized trough username and password in the ...
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2answers
529 views

Self-signed CA and digital signatures

I am asked to design the public key crypto system for an IoT-like devices. These devices are going to be talking to each other over TCP/IP as well as communicating with a cloud-based API server. The ...
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2answers
3k views

Is there any security risk when a certificate authority is used more than all others?

According to NetTrack, Let's Encrypt is now used on more than 50% of domains (51.21% as of April 2018). I know Let's Encrypt helped a lot of people to get free certificates for their websites, so I ...
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7answers
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How do certification authorities store their private root keys?

Knowledge of a CA private key would allow MitM attackers to transparently supplant any certificates signed by that private key. It would also allow cyber criminals to start forging their own trusted ...
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2answers
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Official trusted certificated entities

I am learning about root certificates entities and I have a few questions about that. As far as I know my browser trust in a root certificates entities and I can find the list in "configuration" > "...
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8answers
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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 ...
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3answers
14k 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 ...
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0answers
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cfssl example certificate chain verification failure

I am getting the following error when trying to verify the certificate chain of a dummy root/intermediary/end PKI. root generated as follows: mkdir {root,inter,end} cfssl print-defaults config > ...
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1answer
146 views

Is it safe to commit ascii-armored symmetric private key to VCS?

What is the risk of committing an ascii-armored symmetric private key to VCS where the password lives outside of source control? This is a private closed-source repo. Two helpful topics: When can I ...
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2answers
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IP Security (IPsec) vs Public Key Infrastructure (PKI)

I've found the following question on the internet and don't think the answer is right. Which of the following does IPsec use? A) SSL B) AES C) DES D) PKI The given answer is D, PKI ...
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1answer
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How does SSH know which public key to use from authorized_keys? [duplicate]

When an SSH client connects to an SSH server using public key authentication, the server encrypts a message using a public key from authorized_keys, and the client must prove it can decrypt the ...
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2answers
696 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 ...
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2answers
829 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 ...
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2answers
355 views

Man in the middle attack on browser downloads

I'm writing this post from chrome. If I go to a HTTPS site after this, the public keys built into the version of chrome I'm using will be used to verify the site's signature (unless I misunderstand). ...
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3answers
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What are the accepted naming convention for the terms “public/private keys” and “certificates”?

Is there an accepted naming convention for referring to PKI artifacts? There seems to be a lot of confusion with the naming of artifacts. For example, it seems that some people refer to: public ...
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1answer
339 views

Why is PKCS#7 used as a response to PKCS#10?

Why is the certificate that results from a CSR usually contained in a PKCS#7? The signature of the certificate is contained within the certificate itself so there's no need for an external signature ...
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2answers
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Why does WannaCry encrypt symmetric key with a new per-victim-only public key?

According to this answer, WannaCry will: Generate AES key at victim's system to encrypt victim's files. Generate RSA key at victim's system to encrypt AES key generated above. Encrypt private key of ...
2
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1answer
64 views

What advantages would client-side certificates have over signature based auth such as Oauth2 or HMAC for HTTP Requests?

My application currently supports these two authentications methods OAuth2 and HMAC Auth. OAuth2 https://tools.ietf.org/html/rfc6749 HMAC https://tools.ietf.org/html/draft-cavage-http-signatures-09 ...
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2answers
588 views

Can lack of certificate pinning be considered a vulnerability?

The use of certificate (or public key) pinning can be considered as a good practice for defense in depth, since it protects an application from man in the middle and DNS hijacking attacks. But can it ...
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1answer
80 views

Is it wise to remove redundant self-signatures from my PGP key?

I have changed expiration date of my pgp key several times. Recently I looked at it and started to worry about the mess I can see there: $ gpg --list-sigs AAAAAAAAAAAAAAAA pub 4096R/AAAAAAAA 2014-...
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1answer
88 views

Identify owner of public key certificate

Today I logged in and found these certs in my home directory (macOS): 3d001d000851363136363935_rsa_new.der 3d001d000851363136363935_rsa_new.pem 3d001d000851363136363935_rsa_new.pub.pem ...
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1answer
92 views

Is the certificate I receive back from the CA supposed to be private? [duplicate]

I'm attempting to install a certificate on a web server. I understand there is nothing secretive about the CSR. Obviously, I wouldn't want to reveal the private key I used to generate the CSR. How ...
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1answer
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Why don't browsers check CAA records to help ensure a certificate is valid?

If I understand correctly, Certification Authority Authorization DNS records are used to specify which certificate authorities are allowed to issue certificates for a given domain. If that record ...
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3answers
645 views

SHA1 - S/MIME and CRL validity after deprecation?

In an internal PKI using SHA1 for hashing, will S/MIME signature and CRL/ARL signature be considered invalid in the next few years (SHA1 Deprecation) ? End certificates can be revoked, CA ...
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1answer
40 views

It it possible to host pre-signed html content so I don't need ever to upload my private key to a server?

The question is simple. My private key should only be necessary to resign something if it changes. If I have a static html website, can I use my private key (signed by a CA) to sign all thes html ...
3
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2answers
403 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 ...