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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Does OpenPGP key expiration add to security?

I've created a new OpenPGP key to sign a software package in a source repository with an expiration date three years from now. It seemed like a good security measure, because if the key is compromised ...
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1answer
41 views

Is it possible to give legal value to signed web services?

The context is using digitally signed webservices (with XML-DSIG for example) for e-government interoperability between databases. The idea is to give endorsement to both the data publisher and the ...
2
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0answers
37 views

Out of band signature application for banking transactions

I work on a banking signature project. Signing transactions must be carried out on another application to respect the mechanism "Out Of Band". When the user makes a transaction, he must pass to a ...
4
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2answers
197 views

Certificate Chain - intermediate and root certificate - installed required?

Recently I bought a SSL cert from comodo for my domain - orakoha.com After submitting the CSR etc, domain control verification etc, I am issued with a zip file containing 4 document which I believe ...
3
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2answers
184 views

Is signing android apk file with SHA1 digest secure enough?

Google command line example for signing apk files: $ jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore my-release-key.keystore my_application.apk alias_name source: http://developer....
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75 views

understanding client certificate - pfx on the general

Today I am given a pfx and told to access a website. I have absolutely no idea what was given to me initially, so please kindly confirm my understanding on a general level 1) the pfx is a container ...
2
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1answer
32 views

Does it matter how information is represented prior to signing?

I have messages that will form a permanent record and be stored for a long time. I care about integrity, authentication, and non-repudiation, so I intend to have the clients creating those messages ...
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2answers
40 views

Files related/required to a digital certificate

I am new to digital certification and I am trying to understand it as well as get my domain certified. I know this question may be broad, but can someone give me a general idea of the usage of the ...
2
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1answer
53 views

Signing web forum messages

I maintain web forum software, which is accessible via NNTP and e-mail (as mailing lists). Since NNTP by design allows anyone to spoof their e-mail address, message signing can be used instead to ...
4
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1answer
27 views

Best practice: Should I revoke an identity self-signed using SHA1?

When I first created by PGP keypair, my identity was unfortunatly self-signed using SHA1. I later signed again using SHA512. Does it make sense to revoke the SHA1 signature now or will that just ...
5
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1answer
376 views

self-signatures using SHA1

This page says: self-signatures must not use SHA1 You can check this by doing: gpg --export-options export-minimal --export <keyid> | gpg --list-packets |grep -A 2 signature|grep '...
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Verifying cryptographically signed files when the key has been revoked

This is mostly a question out of idle curiousity. If I use my private key to sign a file today, forming a signature, and distribute that signature with the document to someone they can then use my ...
0
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1answer
48 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 ...
0
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2answers
132 views

is Digital Signature vulnerable on the Internet?

We all know about how Digital Signing works. I just have some questions about vulnerability risk. At first, As I know, the Signature and the Data are separated and we can split the document into two ...
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0answers
27 views

Secure transfer with proxy person in the middle

I am new to cryptography, so I would like some validation. I have an unusual use case that I haven't found described anywhere and would like to get some help validating my approach. Alice needs ...
3
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2answers
66 views

GnuPG does not verify signature while decrypting

I have signed file 1.txt, result file is 1.txt.asc. I changed content in file 1.txt.asc (signed content, not signature). Then I verify signature in 1.txt.asc and I get information that signature is ...
5
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3answers
335 views

Are documents truly “signed” by DocuSign?

I've never been happy with the explanation DocuSign gives for themselves in their own marketing material (e.g. https://www.docusign.com/how-it-works/electronic-signature/digital-signature/digital-...
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4answers
241 views

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 ...
3
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0answers
14 views

How can I improve and secure automated signing?

Automated signing of files, such as software packages or file backups, is inherently risky if a certain level of trust is given to it. Having signing be an automated process means that there's no user ...
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3answers
162 views

Authenticating user in same sub-domain using cookies

We have few in production websites say site1.dom1.com , site2.dom1.com , site3.dom1.com which are just replicas working on different server. Now we want to extend some application on another server ...
6
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2answers
862 views

How does an attack on a digital signature work?

In our IT Security class we have been told that you need CA's to prevent attacks on a digital signature. Sadly, our docent didn't elaborate how such attack would be performed - I can only guess that ...
3
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2answers
110 views

Advantage of group signing over single signing

As I know, signing is used to ensure integrity and authenticity of sender. What is the advantage of group digital signing over individual signing? Can anyone explain this using a scenario?
2
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2answers
134 views

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 verified/...
7
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1answer
77 views

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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1k views

Encrypt files on FTP server

I have a practical situation here, my company is a FTP server provider for some clients. The clients are sharing their files on our FTP server and have had no problem with access management and ...
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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 (http://social.technet.microsoft.com/wiki/contents/...
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56 views

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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1answer
63 views

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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2answers
563 views

Which factors should I consider for devices that accept handwritten digital signatures?

These days many locations ask you to give your signature on a digital signature pad/device. As I am situated in Europe, the EU directive 1999/93/EC seems to regulate it. From what I have found out ...
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1answer
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ADFS: Verify requests from relying party

In ADFS, serveral certificates are used. This is explained (very clearly) on this page: http://blogs.technet.com/b/adfs/archive/2007/07/23/adfs-certificates-ssl-token-signing-and-client-authentication-...
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1answer
74 views

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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5answers
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inquiry about SHA1 with RSA for certificate signature

As you all know, plenty of X.509 Certificates use (PKCS#1 SHA1 with RSA encryption) as the Certificate Signature Algorithm for generating the signature of 2048 Bits long. We know that SHA1 hash ...
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3answers
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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 ...
0
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2answers
75 views

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 ...
0
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1answer
193 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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4answers
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how digital signature verification process works

I am not able to understand that how the digital signature is verified. I know that digital signature will be attached to the message and sent by sender to receiver. then receiver uses the public key ...
2
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1answer
29 views

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 ...
13
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1answer
17k views

SSL Certificate framework 101: How does the browser actually verify the validity of a given server certificate? [duplicate]

Sorry I know this is a complete noob question and at the risk of posting a somewhat duplicate topic. I have a basic understanding of public/private key, hashing, digital signature... I have been ...
4
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1answer
60 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 ...
10
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3answers
360 views

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 ...
0
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1answer
100 views

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 ...
0
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2answers
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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 ...
5
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1answer
621 views

multiple authenticode signatures

Is it possible to have multiple Authenticode signatures in an executable? The Digital Signatures tab suggests you can, so I was wondering if, for example, you can sign an executable with Verisign's ...
3
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1answer
346 views

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 filename....
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2answers
50 views

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 ...
2
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1answer
279 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 ...
3
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2answers
100 views

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 ...
2
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1answer
53 views

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 information....
4
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2answers
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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 ...