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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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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AWS KMS to sign messages - trouble using python's ecdsa lib when getting the verifiying key [migrated]

I'm signing my messages using my code below: def sign_msg_hash(self, msg_hash: HexBytes): signature = self._kms_client.sign( KeyId=self._key_id, Message=msg_hash, ...
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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. ...
19 votes
2 answers
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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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2 votes
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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 ...
1 vote
1 answer
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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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4 answers
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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 ...
-1 votes
1 answer
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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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7 votes
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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 ...
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Does Google Update perform cryptographic checks against releases?

My company is looking to allow Google Chrome to self-update, a necessity as we are finding it difficult to keep up with their release cycle in order to mitigate vulnerabilities. On the pro side, ...
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Role of public and private keys of client certificate in mTLS [duplicate]

I'm curious to know how mTLS works in more detail in regard to client authentication. Firstly, I issued 3 certificates: root CA, server and client. The last two are signed with the root CA. Secondly, ...
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Looking for a solution: trusted identity with corresponding digital signatures (QES) for intercontinental charity

We are looking for a solution to meet the needs of a UK incorporated charity (CIO) that has three to seven trustees from at least three continents. Obligations as trustees of a board include signing (...
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Is there any way I can verify that my app in not modified or tempered (code is changed or something) on clients phone? [duplicate]

I have created an App and made clients install it on there phone. When my app tries to connect to server or request data from my server I want to verify if that app is genuinely my app and not ...
2 votes
2 answers
358 views

Exact meaning of RSA key in `gpg --verify` output

When verifying a pgp signed message using GnuPG, one gets an output similar to the following: gpg: Signature made Fr 07 Jan 2022 13:42:21 CET gpg: using RSA key ...
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double hashing for code signing and verification

I have environmental constraints where the cyber and safety functions are segregated such that safety operations are handled by one unit and cyber operations such as firewall, HIDS, secure storage etc....
1 vote
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120 views

HSM High Volume Keys

Our project is to apply digital signature to PDF, so each user should have their own key pairs and a certificate. To keep key securely, we plan to purchase HSM, but from what I understand HSM have a ...
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How do Cloud-based services provide Qualified Electronic Signatures?

From what I know about QES, they come on smart cards and USB tokens and are password protected. When a site asks you for a client certificate, you need to have it plugged in and enter the password ...
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1 answer
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Git Signing commits in a private repo

Linus mentioned in 2009 that "Signing each commit is totally stupid". Has the common view evolved on this subject since then ? Doesn't it protect against someone usurping your identity to ...
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mTLS Client Authentication by Signing Arbitrary Message using Browser

this is my first post here in the area of ​​security and encryption. I will try to be succinct, and let you know that I am not an expert in security. Context: My client (visitor) has an X509 ...
3 votes
2 answers
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How can I prove the content of a PGP-encrypted message to a third party?

Imagine this scenario A StackExchange user sends you a PGP-encrypted message You decrypt the message and discover that you are being blackmailed You report the message to the admins but they are ...
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Parse VBA Macro Digital Signature

When I open up my macro-enabled office files (i.e., .docm, .xlsm, .pptm) that contain signed macros as a Zip file, I see the following three files which I assume contain the digital signatures for the ...
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Why does length of Signatures in two certificates using same Signature Algorithm sha256WithRSAEncryption is different?

I have this recent Wikipedia certificate issued by intermediate CA Let's encrypt: Certificate: Data: Version: 3 (0x2) Serial Number: 03:95:2f:46:69:de:e4:d2:19:35:7f:f0:...
2 votes
2 answers
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Digital Signatures validity when changing Certificate Authority

An enterprise has its internal PKI-1 (Root CA) that issues certificates to sign document using CAdES-C (CAdES-LT); with Complete Validation Data References and revocation references. Now this ...
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Strange keystore from payment processor

I am working on an older software for a company at the moment and in my work have been upgrading a number of libraries. The app connects to a web service hosted by the third party payment processor, ...
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Is DSA-1024 safe to sign package repositories ? What are the reasons?

I recently found that the latest release of a major Linux distribution (MX Linux) uses DSA-1024 in /etc/apt/trusted.gpg and in /etc/apt/trusted.gpg.d/*.gpg It also probably uses SHA-1 as the signature ...
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Signing Binaries in CI/CD

I've been considering how continuous integration/delivery environments handle code signing. If I maintain some open source project which uses a CD environment to build binaries to ship to users, I may ...
1 vote
1 answer
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Keeping a whitelist of GPG keys on git server

Why don’t git servers (gitlab, github, etc…) allow for a whitelist of public GPG keys allowed to sign commits? For example, Alice owns a GPG key with fingerprint 0A1B2C3D while Bob’s is 4E5F0A0B. They ...
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Possible to limit an SSL certificate holder to issuing redirects?

Is it possible to issue an SSL certificate that limits the certificate holder to issuing https redirects? Or more generally, limiting the holder to issuing specified data through the secure pipe, ...
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Docker: How to download & verify a publisher's root key (out-of-band, distinct-domain cryptographic verification, WoT)

For a given publisher of docker images on Docker Hub (let's say debian), how do I download their root release/image signing key and verify its authenticity from multiple sources out-of-band from each-...
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How hard is to reverse engineer a signature for a given message?

Given the following situation: User makes a request for temporary access to a video Backend responds with a json file containing timeAllowedInSeconds: 5 Backend also responds with the signature of ...
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