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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Digitally signing a digital signature

When might it make sense to digitally sign a digital signature?
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DSS digital signing approach

Under the DSS approach to digital signing, what is the advantage of using two pairs of keys for each signature?
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Is it possible to digitally sign an email twice?

User A encrypts an email with the public key of user B and digitally signs it. User B receives this message and decrypts it. B wants to forward it to user C, encrypts it with C's public key and signs ...
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Verifying android application integrity from server side

I have android applications (Mobile banking) that connect to my server and do online transactions (via Internet/USSD/SMS), I want to make sure those clients are not tampered with and are the original ...
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Different Microsoft-signed excecutables have apparently the same signature!

On Windows 10 systems, I found two versions of bootsect.exe (a Microsoft-supplied utility that writes disk boot sector) with different hashes (SHA-1 9b7463c79460a55a36b53bee0889f894b2379ec3 for one ...
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PGP vs Hash functions

What is the difference (in terms of security strength) between checking a package' integrity using pgp and hashing functions (i.e. sha256)? Isn't pgp less secure as the verifier must trust the ...
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69 views

BLS signature java implementation needed (if possible, along with some example code)

I need to sign a string with the shortest digest possible using regular certificate like X.509. As far as I understand, I will have to transform the string to the sequence of bytes, then sign. After ...
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Signing a code and application

I want to send my application to different servers/terminals with content integrity and confidentiality. So, I need to some process to sign my code and application before sending it to servers and to ...
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49 views

What does an OpenPGP signature consist of?

I don't understand how OpenPGP signatures work. I have a picture which I want to sign, and a digital certificate which consists of my name and email address and my public key. Additionally, a digital ...
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How to acquire DNSSEC root trust anchor from IANA?

I want to establish trust in a DNSSEC record. I found, that it can be done $ dig +sigchase +trusted-key=./root.key @8.8.8.8 eesti.ee root.key could be obtained with $ dig . DNSKEY @8.8.8.8 | grep ...
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Where in the CSR is the public key?

I am reading http://www.akadia.com/services/ssh_test_certificate.html In step 2 openssl req -new -key server.key -out server.csr server.key is generated earlier using openssl genrsa -des3 -out ...
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Self-signed cert - how it works

I am new to SSL / digital certificates / signatures. What I know is that a digital signature must be verified/decrypted using the public key. So a cert that is signed by a CA must be ...
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28 views

Authenticating a user by verifying a signature

Background I'm setting up an API which will be used primarily over HTTPS (only calls not needing any security what so ever is available over HTTP). Some aspects of it need to be accessed only by ...
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SSL digital certificate process - high level

I am a project manager and is touching on an IT project consisting of the usual 3 tier - web/client - middleware - database. In this case, I have an web server and needs to implement SSL ...
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Use GnuPG to verify if specified user signed file

To verify if file is signed correctly we use command: gpg --verify <file_name> and the output shows if file is signed correctly. And if it is, then signer name is shown. But is there ...
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Is this a weakness of enveloped XML signature?

There might be a problem in many applications based on XML signature verification (provided I am not wrong, of course). Let's have a simple XML message with an enveloped XML signature: <?xml ...
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RSA blind signature vs signing a hash

My understanding is that the key feature of a blind RSA signature is that the signer is unaware of the contents of the message being signed. How is this different from simply hashing some data and ...
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1answer
175 views

Microsoft and SHA-1 deprecating on Windows 7

Microsoft states: Effective January 1, 2016, Windows (version 7 and higher) and Windows Server will no longer trust any code that is signed with a SHA-1 code signing certificate and that ...
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Deprecation of SHA1 code signing certificates on Windows

I have been keenly following the issues with regards to Microsoft deprecating the use of SHA1 code-signing certificates for Windows executables ...
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Sign a callback URL

I have a Single Sign-On system that works this way : User clicks link on clientsite.com that redirect him to mastersite.com?returnTo=http://clientsite.com If auth is valid, the user is redirected ...
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Why would some Windows executables not have a “Digital Signatures” tab?

Why would some executable on a Windows 7 system not have a "Digital Signatures" tab? (With this question I am referring to those executables that are not part of Windows OS and to which the ...
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Can I do an enveloping XAdES signature on binary content?

I need to sign some binary content (scanned documents) with a digital signature compliant with European norms, CAdES - XAdES. One option would be to use this library to do a XAdES signature. Is there ...
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How do I produce a CA signed public key?

I have a need to have somebody else encrypt secret data with my public key that I can then decrypt with my private key. I have produced an RSA private/public key pair with OpenSSL gave them the public ...
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Verification of a timestamped PDF

I'm kinda new to the process of timestamping files to provide digital integrity. For testing purposes, i use tsa.safecreative.org for PDF files. Now i've signed a couple PDF files and if i open up ...
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How does a Sign tool work?

My basic understanding about sign tool is: 1.It loads the zipfile(may be exe,jar,ddl,apk..) which has to be signed to its memory(cache memory of the sign tool). 2.It will verify it, and unzip the ...
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Client side signing of a file(.exe,.dll,.jar..) using CA issued certificate and signtool [closed]

In a current project we have purchased certificate from a trusted CA and have installed in a host, sign tool is also installed in the same host. All the files which we develop(jar,dll,apk,exe etc..,) ...
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Subresource Integrity versus signing

The draft spec for subresource integrity is straightforward: This document specifies such a validation scheme, extending two HTML elements with an integrity attribute that contains a ...
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CMS signed data OpenSSL verification error

I have a CMS signed data that is successfully verified through Java BouncyCastle library. When trying to verify through OpenSSL, I am getting the following error: >openssl smime -verify -inform ...
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Standard digital signature data representation

I am creating digital signatures using various scheme, e.g. RSASSA-PSS. The result is bytes that represents signed data with private key. I would like to store signature as a standard data ...
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74 views

Strategy for electronic document (PDF) signatures

I'm treading into the murky waters of electronic document signatures, and I'm having trouble figuring out the right approach to deal with my requirements. I think this should be pretty ...
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For X.509 Certificates where is the actual digital signature?

When you open up the certificate information from your browser and go to the details tab there is a bunch of information for various certificate fields. I am wondering which field contains the actual ...
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How to make sure nobody has read this!

Is there any computer/server which would allow me to get "guaranteed read access history" for files? For example, suppose I made a file with my plaintext passwords and simply wanted to make sure that ...
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Is this a secure Digital Signature + Encryption method?

I am trying to wrap my head around Digital Signatures and how RSA Encryption supports them. And which order to do them along with what specifically to encrypt. So say we have Alice and Bob and a ...
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what is worth a digital signature based on email address only? [closed]

I have noticed that most digital signature providers do not try to certify anything but an e-mail address, while it is quite easy to create an email address without disclosing any personal ...
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Smartcard authentification: encrypt/decrypt or ECDSA?

I'm implementing a simple door access control with smart keyfobs. At the moment I send a 32 byte message to the keyfob which it signs with ECDSA and I verify the authenticity with the public key. ...
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deceptive digital signature?

I am new to cyphering and I try to understand this case : my government sends me so-called "digitally signed" PDFs, as you can see below (text only, after "Thanks"). Although there is a certificate ...
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Public Key Infrastructure: Sending data securely to CLIENT?

Ok, so been looking up public key encryption and using it a bit around some of my web applications. From some testing, I understand that the server contains two keys and sends the public key to the ...
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OpenSSL check if a SSL certificate is SHA-1 or SHA256 signed

How do I check if an OpenSSL certificate issued to a site is SHA-1 or SHA-256? I have a quite a lot of intranet sites using OpenSSL certificates and I am a bit confused as when I check the certificate ...
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Is there a way to prove some content came from a specific website?

I guess we can all agree that a screenshot of a website proves nothing; one can edit the HTML as much as one likes, take a screenshot and show a website displaying false information. As far as I ...
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29 views

Authentication using a digital signiture

I'm new to the world of digital signatures and encryption and I'm trying to learn more. I was wondering, how or if an authentication process (login or sign-in) can be performed using a digital ...
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In the context of advanced electronic signatures, what does “sole control” mean?

To satisfy the conditions for an advanced or qualified electronic signature, the power to sign must remain under the "sole control" of the signatory. Can anyone provide concrete examples of what this ...
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Need raw certificate/key to sign PDFs via Java app. But vendors seem to only sell HSMs for this. What to do?

Our organisation wants to purchase a digital signature certificate for signing financial PDF documents. We want to automate this process, so we'll be having Java code do the signing work. For that the ...
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Make signed file from content file and its detached signature?

I have a text file which I will call filename.txt. Firstly I call gpg --output filename.asc --clearsign filename.txt Signed file filename.asc is created. Then I call gpg --armor --output ...
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signature and padding

I use JcaContentSignerBuilder to sign a self-signed certificate but I don't know what the default padding is. My requirement is that I must NOT use PKCS#1.5 padding. The code I use is below - can ...
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What are some Linux commands for genrating and verifying digital signatures?

I am attempting a workflow to exemplify the process of digital signature using asymmetric cryptography. If I understand correctly then the public key and the private key in an asymmetric ...
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How is the signing of an OpenPGP public key realized technically?

I recently have signed the public OpenPGP key of a friend of mine. Curious to see, which effect this would have on the actual key, I compared the key before and after signing it. What I found was that ...
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Long term trust anchor validation

Let's say someone signs a document for long term validation using a certificate issued by a trusted CA. Throughout the following years, the document is timestamped again and again by multiple trusted ...
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1answer
61 views

Generating Own SSL certificate using DSC issued by a CA

Ok. So, here is what I know: SSL Certificate are used to verify domain for HTTPS protocol. These are issued by a root CA to ensure that it can be trusted by anyone using the website and trusting the ...
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Is this explanation about how SSL Certificate Signatures work correct?

I was reviewing some information about SSL certificates and came across an explanation I believe to be incorrect. The explanation is of how signatures and hashing algorithms work in the context of ...
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In message signing, is the digest encrypted with a generated symmetric key or with the sender's private key?

I understand the encryption process uses a generated symmetric key to encrypt a message, and then encrypts the symmetric key with the receiver's public key before it is sent across the wire. This ...