Questions tagged [digital-signature]
A digital signature (not to be confused with a digital certificate) is an electronic signature that is used to authenticate the identity of a message sender or document signer, and usually to ensure that the original message/document content is unchanged (document integrity).
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How XAdES protects against tampering if the certificate is embedded?
Signing XML file with XAdES extension provides the X509 certificate.
What is the security point if the certificate is given? Anyone can tamper the data with its own certificate, right?
I used to work ...
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Digital Signatures [closed]
In RSA signatures, Alice signs the message using her private key, and Bob verifies the message using Alice's public key.
If an attacker has the signed encrypted message, then can they also verify the ...
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Java Cryptography classes - program agnostic usage
We are planning on implementing encryption or digital signatures using any of the available classes provided by the Java Cryptography Architecture (e.g. KeyPair, MessageDigest, Cipher, KeyStore, ...
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My web application needs to have my users' private keys to sign documents on their behalf. How do I handle that?
Our web application issues governmental documents for our users. Every one of those documents needs to be signed with a private key. However, because our users find it cumbersome to point their ...
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OIDC ID Token nonce as "poor mans digital signature"
In absence of better solutions, is the nonce is an OpenID Connect ID Token usable to serve as digital signature. The process would be as follows:
A hash is created from the to-be-signed document/...
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Over what fields is the X509 hash computed over? [duplicate]
Is this how X509 certificates are verified to be valid?
The receiver receives the certificate
Look at the issuer of the cert, and find the public key of that CA (its hardcoded in the application or ...
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What could be the correct and secure ways to store and manage public keys?
I am developing an open source project(PKDSA) that uses ED25519 and ED448. My purpose of this project was to help others to enable user-secretless based passwordless authentication.
There're a lot of ...
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How does the client get the certificate (and public key) of the delegated authority (OCSP responder) to confirm the response in OCSP?
I have one question regarding the OCSP protocol to check if the certificate is revoked or not. The question is about checking whether the intermediate CA certificate immediately below the root CA is ...
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How to get a CA into a Trust Chain
I'm using Google CA Service Provider in the Google Cloud to issue key materials on their FIPS-140-2 Level 3 HSMs (google's service).
I intend to send the attestation bundle alongside public keys and ...
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Payment Gateway rejecting Digitally Signed Payment Message
I am new to digital signatures. I read many problem statements, solutions, and documents but nothing came to my rescue.
Payment Message (Text) needs to be digitally signed with the following specs as ...
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Need for authentication in an offline system
I need to design a scheme, where access to an offline System is granted based on some kind of information/proof of knowledge, provided by a separete system, Prover system.
I'm in position where I can ...
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qualified e-signature long-term security
I'm considering to obtain a QES (Qualified electronic signature). But I'm concerned about long term security.
The hypothetical scenario is lets say after 10-15 years the algorithms are cracked or ...
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Does verifying a code signature require making a network connection?
Does Windows 11 need to make a network connection to verify a code signature for a .exe or .dll file?
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Can an attacker flip bits of a signature to create DoS?
Assume two parties communicating. A sends a message to B signed with its private key. B received the message and verify it using the public key of A. Can an attacker launch a DoS attack by flipping ...
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Secure boot + full disk encryption, should I sign the kernel?
I'm redoing my laptop installation from scratch, and this time I want a full secure boot chain.
Here's what I did so far :
Enroll my own keys in the UEFI firmware
Sign my grub bootloader
Full disk ...
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e-signature + digital signature aws md5
I am trying to implement e-signature + digital signature to secure the e-signed document from altered, something like Docusign. I am using AWS s3 to store the documents.
My question are:
Is MD5 (...
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What is the most secure hardware option for the use of personal eIDAS compliant QES in the EU?
I know that there are two approaches, one with local capsulated storage, such as USB token or smartcard, and the other with cloud-based key vault. Both are secured with a PIN that has to be entered in ...
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Help understanding PKI MTLS and digital signature architecture
I'm building an identity service using PKI and MTLS for authentication where users are supposed to be able to sign data e.g. a json string or a document.
Where I am now
I have implemented working MTLS ...
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Is there any use case of DAA (Direct Anonymous Attestation) in TPM?
I want to know the use cases of DAA (Direct Anonymous Attestation) in the real world.
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Is it possible for an app to sign data it generates so that the data can be guaranteed to come from the app? [duplicate]
Is it possible for an app binary to sign content generated by the app such that a verifier can confirm the data was indeed generated by a specific version of the app?
For example:
A mobile app from a ...
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Confusion Regarding TLS Handshake and Key Exchanges
I know much has been written on this topic, but I am still stuck on some on the details of TLS handshake and I would like to have a better understanding of what happens. I've been using several ...
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How does a digital certificate prove authenticity?
Imagine the following scenario:
We have Bob that wants to send a message to Alice. Both have a public/private key. Bob uses his private key to sign the digest (hash of the message) with it's private ...
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mTLS on webhooks
I'm not understanding how does Sendgrid verify that's it's me who's sending them the HTTPS request on their webhook endpoint.
Specifically, in their docs they show how to obtain their public key (to ...
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Does signing make any sense when encrypting with secret key is used?
When I use secret key which only one server know for symmetric encryption done with XChaCha20-Poly1305, is any benefit to use signing aswell? As long as only one server knows the secret, doesn't it ...
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Do git commit signatures reveal key uid if different from git email?
I have a gpg key linked to my identity and real email address. I also use github with their private email functionality "id+username@users.noreply.github.com", which I set as my git email. ...
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What exactly happens when I "validate" a digital signature?
Context:
I'm filling my taxes and my country requires me to upload certain documents from my employer to verify the numbers I give to the government. These documents are "digitally signed", ...
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Encrypting content with assymetric key pairs as a form of signing [closed]
The use-case is as follows:
There is a signer that have a claim or document D who wants any client to be able to verify that D has not been tampered with.
I suppose one way to do this is to use ...
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Reset forgotten subkey password using master key?
Problem
For some reason I forgot the passphrase for my GnuPG signing subkey, but I have my master key stored in a separate device. Is there a way to regain access to my subkey? Or should I replace my ...
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Is it normal, that some companies just sign the txt file which contains the sha value of the program?
Scenario A: Suppose I have an .exe file, the provider offers a sha1 txt file with hash value and this txt file is gpg signed. So I check if the hash value matches the exe file and then download the ...
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Best practices for verifying authenticity of public key
When one desires to share their public key openly, besides sharing just the key itself:
How does one verify that the key belongs to who it claims to be owned by?
What is the use case of the key's ...
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Why a public key must be signed with its private pair in PGP
I know about the trust web in PGP. When you sign a key, everybody that trusts you will trust the person with that key. But what is the point of self-signing a key when anybody else can do that with ...
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Can't sign commit with yubikey, GPG missing something
I don't know much about how yubikeys work, but I'm trying to sign a commit with one of them and I don't even know how to debug the problem. I got:
gpg --list-keys
/home/lz/.gnupg/pubring.kbx
----------...
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Managing multiple GPG keys
I'm currently attempting to setup my personal GPG key suite for the next few years, and I'm running into a question I don't have a ready answer for. I own 3 yubikeys, Primary/Secondary/Offsite Backup. ...
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Using Openssl for Package signing with timestamp
We started with openssl dgst to sign and verify packages successfully. Then we thought we should do a timestamped signatures. That's when the process is bit unclear.
We used the openssl ts commands to ...
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Adobe uses CA signature type as identifier on signatures created with user certificates
I am testing several PKCS12 keystores with ECC type keys, generated by a CA with RSA key, to sign PDF documents. I have also tested with my own certificates from a demo CA certificate. I use Adobe ...
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How reliable is Window's verified publisher system?
I assume anyone can with some effort add their certificate under name X to their database, in that case, is there anything stopping a fake publisher from adding themselves with the name of a legit ...
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Why REST APIs that do not use RSA encryption to secure API keys?
After using many APIs, I noticed that most of them offer 2 keys: API Key and Secret Key.
The secret key is used to sign the request body with HASHAGE algorithm, the most used is HMAC SHA256. This ...
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Why trust a PGP signature if it is distributed along with the data being verified?
Many downloads offer an OpenPGP signature, which can be used to verify the file, but if a hacker manages to manipulate the file, then he can also simply change the signature key, or not?
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How to prove the authenticity of the telemetry message?
I'm curious what is the most widespread way nowadays to sign the telemetry message from a software program to prove its authenticity to the receiver?
Imagine the software (which can run on-premise, at ...
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How to generate SSH keys inside yubikey?
How do I generate SSH keys inside my yubikey, on Ubuntu?
There seems to be nowhere to look for this info.
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How to license an offline software that automatically expired in the given amount of time? [duplicate]
Suppose I have a software which I sell to customer to use. I want to include a license that will be expired in let's say 1 year, so that customer need to renew their package.
I want to prevent the ...
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Strip CMS Signature from file (using openssl?)
I have a lot of binary files that contain some data that is signed using CMS.
The files have the form:
$ openssl cms -inform DER -in test.cms -cmsout -print
CMS_ContentInfo:
contentType: pkcs7-...
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How can a .exe be modified and still keep a valid digital signature?
When a Windows .exe installer is code-signed, I thought that modifying a single byte (thus changing its SHA256 hash) would make the digital signature invalid, but surprisingly, this is not true.
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PGP "real" encryption with private key
When explaining the concept of signing a message, often it is presented as "encrypting with your private key", so that somebody who has the public key can "decrypt" the signature ...
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Digital signature for API authentication feasible?
Could it be practical to authenticate API request through digital signature (based on headers and message body)? This would be asymmetric instead of something like HMAC which is not a signature. ...
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Should refresh tokens be signed?
I'm not using an identity provider. I have a small system with access and refresh tokens and it works well.
Assume the system follows the "typical" approach:
when user authenticates or ...
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Terminology for exchanging one piece of signed information for another
Applications that use cryptographically signed information for multiple purposes have the risk that one piece of signed information can be exchanged with another. When you use JWTs as session tokens, ...
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Is it possible for a company to buy a signing certificate so that everything it signs (Software,SSL, Documents) states its from that company?
If I work for a company that wants to sign its own certificates for its website, documents and software it writes, is it possible? I have read a couple of post on here from around 10/8 years ago but ...
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What signature and certificate signing is all about
I know that X.509 certificate signing process includes creating a CSR (certificate signing request) and then the following happens:
Some data's from the certificate to be signed hash is computed ...
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How does "./" affects signature generation for files, in a PHP based web application?
I am solving a lab related to serialization vulnerabilities. It deals with retrieving files based on the signature. The theory of the lab states as quoted, "Adding ./ will still give you the same ...
