Questions tagged [pki]
PKI is short for Public Key Infrastructure. The foundation of a PKI is the certificate authority (CA), which issues digital certificates that authenticate the identity of organizations and individuals over a public system such as the Internet.
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Using plaintext + ciphertext combination as substitute for authentication/signature in elliptic curve cryptography
I'm working on a system where I need to sign some data using an ECC private key and share the data and signature over a BLE ADV packet. Since an ADV packet is limited in space, I can't use a full ...
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Decentralized identity, how to prevent duplicate uses of the same identity
In a system that relies on decentralized identity, is it possible to prevent duplicate uses of the same real-life identity, i.e. same real-life person creates more than one user entity (each is ...
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How does padding in RSA prevent existenial forgery attacks in RSA?
I am trying to understand how adding padding like the PKCS1.5 RSA signature scheme can prevent the existential forgery attack in RSA. Is it just by changing the structure of the message?
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What is a website's private signing key used to sign?
I am trying to understand digital signatures and digital certificates. I know that digital certificates verify a server's public verification key but what does the website's (client) private ...
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Timestamp quantity for PDF long time archive
How many timestamps are issued when someone signs a PDF with timestamp Long Term Archive (LTA)? Why is it necessary to issue more than one timestamp?
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How does TLS 1.3 provide authentication without using the public key to verify that the server has a private key?
In the TLS 1.2 handshake, after checking the certificate, the public key from the certificate was used to encrypt the data to create a symmetric encryption key, hence the authentication took place on ...
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Is it possible to define a new custom signed attribute for CAdES?
Is it possible to introduce a new signed attribute in the CMS Advanced Signature format (RFC 5126) for a custom data type? I want to include location data from GPS or Galileo and extend CAdES for my ...
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Does code signing Certificates need a key Pair? or a single Certificate
I know that SSL Certificates use a private key on the server side and the public key for verifying it on the client side.
I am wondering, is it the same for Code Signing Certificates?
Or do they just ...
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Is there any way to (irrevocably) *transfer* a private key to another person?
Let's say that Alice is the administrator of a group. For each message generated by a group member, Alice uses an administrator's private key ($sk$) to sign it, indicating that this message has been ...
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Can a user set his public key without knowing its corresponding private key? [closed]
I'm wondering if in public key infrastructure (PKI), a system user be able to set his public key without knowing its corresponding private key.
Can this be done?
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Is there a way to modify an existing RSA key pair so that the functionality remains?
I have an existing RSA key pair, how to 'derive' a different key pair based on the existing one so that the encryption decryption functionality remains but the original key isn't interchangeable with ...
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Are PKI PQC algorithms slower than their nonPQ counterparts? (e.g. NTRU vs RSA)
Are the methodologies (hard problems being used to secure the encryption) in post-quantum algorithms inherently slower than what we have right now? If not, why weren't they used initially?
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Distributing the Master Public Key in Identity-based Encryption systems
I was just wondering how the private key generator should publish the master public key inside of an IBE system. This key is needed for all devices in the network to derive the public key of receiving ...
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Comparing digital certification and blockchain certification
I am trying to understand the benefits of using blockchain technology in document certifications such as university diplomas. I would like to know the difference between digital certification and ...
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Why does Index Calculus work?
I understand how the Index Calculus algorithm works - I know & understand the steps. I understand how the steps are derived. However, I am not able to figure out why it works.
I can understand why ...
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How or in which format should Schnorr signature keys be stored? [closed]
I would like to know if there is any standard for storing public and private keys for Schnorr signature
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Pollard's p - 1 - how do you set the bound & how do you set the base numbers
In Pollard's p-1 algorithm for factoring N, you try to find a L such that p - 1 divides L. Then you check $gcd(pow(a,L,N)- 1, N)$. If 1 < gcd < N, then you have found one of the factors.
I have ...
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Why is factorial used in Pollard's $p - 1$ algorithm?
Why exactly do we use factorial for finding an $L$ which is divisible by $p - 1$?
Pollard's algorithm is about B-powersmooth numbers & not B-smooth numbers. So where exactly does the factorial ...
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Does applying a "PushEntropy"-function increase security of a private key?
I was just reviewing the source-code of the NBitcoin-package. As far as i can see when you create a new bitcoin-keypair
Key privateKey = new Key();
(without passing ...
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Automatic csr sending
In our project we have grpc server and clients which should satisfy mutual tls. So, there is CA and clients generate csr to sent to CA to signing it. Now I need to send csr manually to CA to sign it ...
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How does TLS 1.3 sign key exchange?
From this site: https://tls13.ulfheim.net/ and from https://www.rfc-editor.org/rfc/rfc8446#section-2 I can't find the part in which the exchange of keys is signed, isn't one of the parties "...
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Exploitability of AES in CBC Mode For Recovery of Plain Text
I'm aware of existing literature that shows in a comprehensive manner just how simple it is to tweak the ciphertext of AES-CBC such that the decrypted message ends up being entirely different than ...
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What are the rules regarding to numbers in RSA?
I'd like to have a small sanity check first: As far as I understand, diffie-hellman is all about that fact that, given the generator ($g$), the modulo ($n$) and the remainder ($c$), it's hard to find ...
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Clarification on the TLS verification process
I am reading this article in my attempt to understand how the TLS verification and chain of trust works. In the piece I come across a section that I am not sure I understand.
In the simplified ...
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What exactly is Let's encrypts chain.pem file?
While trying to understand the use or meaning of the fullchain.pem file created by let's encrypt I stumbled upon this post in which ...
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What are the contents of a certificate and how can I view it?
I understand on a conceptual level that a certificate is nothing more than just a verified public key. The next question I have, is how exactly do I see the contents of a certificate? Apart from the ...
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Enforced complete decryption in pki schema
I want to use PKI to encrypt a message. How this generally done is to PKI encrypt an AES key and then encrypt the message. The problem(in my case) with this method is that you can also ask someone to ...
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Elgamal Encryption: Why does Bob get to reuse his keypair while Alice has to generate a new one for every message?
From Christof Paar's book
The protocol consists of two phases, the classical DHKE (Steps a–f) which is followed by the message encryption and decryption (Steps g and h, respectively). Bob computes ...
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Why is confusion & diffusion not required PKI encryption schemes like Elgamal encryption?
The Elgamal encryption scheme is a Multiplicative Mask with the shared key. It doesn't seem to have any confusion or diffusion.
So why is it not necessary here as compared to Block Ciphers?
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How to securely share AES key between two remote devices (client and server) through UDP protocol?
I have two separate system (client) and (server). I am having a problem which is to encrypt a message from the client and decrypt at the server. In order to do that, I am required to transmit my key ...
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What if the CSR is intercepted in transit while sending it to CA?
I was studying PKI the other day and I had a serious thinking about the following question.
What is CSR? - It is a block of encoded text that is given to the CA when applying for an SSL certificate ...
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MPC protocols in plain/CRS/PKI models
I have seen that in MPC multiple models in different dimensions can be envisioned, like asynchronous vs synchronous networks, access to broadcast channels, and so on. However, a particularly ...
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What's the downside of using X.509 in SSH instead of PKI
ssh uses public keys for authentication and not signed X.509 certificates. Specify a drawback which would be the use of X.509 certificates instead of public keys.
I've tried to look up a lot of ...
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Encrypt text message with Wireguard public key
With its public and private key(s), Wireguard looks a bit like PGP. But it is used for encryption of network packets and not normal text messages. I'm on a system with Wireguard already installed and ...
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Converting raw ECC private key into ASN.1 DER encoded key
I created a random integer array of 32 bytes to use as my private key for secp256k1 curve.
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FLT is partly applying to RSA equation, and also relation between ED mod phi and Phi + 1 mod N
After numerous attempts from myself and all of you guys, I finally came to understand RSA. I can now prove it and understand how I got there. But I still have some very few polishing questions.
1) We ...
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Relation between $N = P \times Q$, and $\Phi(N)$
When studying RSA, and proving simple concepts to myself, I went and understood groups and rings, but I failed to understand Lagrange's theorem.
I did understand how from invertible finite groups I ...
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Conditioning access to private key?
I would like to provide a public/private keypair to a user, but require that the user obtain an authorizing key before being allowed to use the private key. I don't want the authorizing party to have ...
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In PKI, with a hash-encrypted message (first hashed, then encrypted), how is the plaintext ever retrieved?
Consider a normal PKI encryption flow - hash the plaintext, then encrypt the hash with the private key of the sender and then encrypt it with the public key of the recipient. All this is good - and I ...
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What is the difference between PKCS1 v1.5 and PKCS7? Is PKCS7 a superset of specifications in PKCS1 1.5?
I have a requirement wherein we have to verify the PE binaries generated for an aarch64 platform.
These binaries are then signed using the opensource sbsign tool ...
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What are some examples of out of bound channels that work over the Internet in practice?
If I want to verify a public key (be it RSA, PGP, etc.) with another client over the Internet only, what are some viable out-of-bound channels for verification? Which channels have been used in ...
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A simple misunderstanding of SSL/TLS
I just came to learn about Deffie Hellman Key Exchange. And a little bit about RSA.
I came to DH from something about SSL. From what I understood before is that SSL uses DH and TLS uses RSA, but after ...
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Understanding need for PKI
For simplicity let's say I only have RSA and AES on my hands and I want Alice to talk with Bob over a secure channel. With secure I am implying no MITM and Alice and Bob know they are talking to each ...
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How are certificate status obtained on browsers?
There are two ways of checking the status of a digital certificate:-
Offline Authentication (CRL)
Online Authentication (OCSP, SCVP)
Several browsers (like Mozilla Firefox) have given up the use of ...
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How is Cross-Certification implemented?
I am currently learning about Certificates in Public Key Infrastructure.
Cross-Certification exists as an alternative because the concept of a single monolithic CA certifying every possible user in ...
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Nomenclature of Certificate Authorities and Certificates in PKI
In PKI there are different terms to identify certificate authorities in the chains. All terms I know of are as follow:
Root
Subordinate
Super
Intermediate
I see all terms used interchangeably in the ...
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Sign file (Client-Server) PKI-CA [closed]
I have a use case, the IoT system sending a signed file to the data center and I have an internal CA to read the corresponding public key to verify the signature on the signed file.
I am not sure ...
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Windows certreq full response file [closed]
I'm using the Windows certreq command line tool to submit a CSR for signing to a Windows Server CA.
...
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Include TSA Certificate in Timestamp Request
I'm currently working on Timestamping and stumbled upon a parameter fRequestCerts/requestSignerCertificates/certReq that according to the documentation (1, 2) tells a TSA to include the certificate ...
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How are public keys securely and reliably obtained across the internet?
I've just decided to start learning all about PKIs, and I have come across what seems like a paradox.
When fetching a public key from either a server or a CA, how can we be sure that the public key ...
