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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RSA-Based Signature Algorithms

From Beginning Cryptography with Java - chapter 4, digital signatures: Signatures are created using the RSA algorithm by applying the RSA algorithm using the private key and then distributing ...
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Trust on certificate authorities

If I as layman don't err, there are in banking controls, from both internal and national oversights, of the work done by the employees. These are apparently effective, since the details of ...
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488 views

How to verify full USB drive's digital signature

There are various ways to verify the validity of a file, usually checking the MD5 checksum or OpenPGP signature. Is it possible to do the same for a full USB Drive? I'd like to be able send a USB ...
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587 views

Is piping a `ssh-agent` signed message as a password secure?

There's an encrypted filesystem on a server I ssh into using public key authentication. Since a forwarded ssh-agent can deterministically sign a message (see also the ssh-agent protocol section ...
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1answer
139 views

Why do I have keys of strangers in my GPG keychain?

I'm going though my GPG keychain. I've got a key for a few strangers in my keychain. I don't recall exchanging keys and I'm not sure how the public keys came to be installed in the keychain. I think ...
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2answers
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Can the client certificate authentication process treated as a user digitally signed the content(and then get verified on the server)?

The authentication was triggered by certain event (like approving button) on the form. In the process of client certificate authentication (in IIS), user was asked to use their PIN (private key) and ...
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1answer
117 views

Is this signature methodology secure?

I'm working on authentication for my JSON-RPC API and my current working strategy is using signed requests sent via POST over SSL. I'm wondering if anyone can see any vulnerabilities that I haven't ...
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1answer
292 views

how to verify file signature by client PGP

Currently working on verifying and signing a file via GNUPG, given that I've already signed a file, given the clients the .sig and public key, is there a way for a client to verify the file without ...
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291 views

Is there an algorithm to generate digitally signed URL links?

Scenario: Alice prepares an URL link to Bob's web service (e.g., http://www.bob.com/sensitiveData/123?login=mallory). Alice gives the URL link to Mallory. Mallory follows the link to trigger an ...
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PKCS7 encoding in Java without external libs like BouncyCastle etc

I am working on signing and encoding of CMS/PKCS#7 messages (something similar to C# SignedCms). I have x509certificate from the keystore, rsa private key, ContentInfo. ContentType is "oidPkcs7Data". ...
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Can a certification authority sign another CA's certs?

Disclaimer: I have low knowledge of X.509 and PKI, so I would appreciate an answer that is not entirely technical, i.e. by using real-life example scenarios.) I was searching for information ...
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128 views

Is it possible to add backdoor to a file with the same size and crc32 checksum (4bytes)?

Is it possible to add backdoor to a file with the same size and crc32 checksum (4bytes)? (The file does not contain byte code, it contains program code as text. The language is PHP.)
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Does a PGP signature provide integrity verification?

Many websites including OpenSSL's website provide downloads along with MD5/SHA1 checksums sometimes in addition to PGP signatures for the files. Simply put, do PGP signatures provide file integrity ...
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1answer
445 views

How to sign data with OpenSSL 0.9.8?

I am building a license generator for nodejs and I am currently testing on Heroku. On my local machine running OpenSSL 1.0.1g, I'm able to test my key pairs (sign and verify) like this: # data.txt's ...
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2answers
79 views

Is it possible to sign/verify a key-pair?

We currently have the need to authenticate and verify generated keypairs. Our system allows users to register for our service which generates them a key-pair for use on our network. We are in need of ...
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1answer
243 views

RSA vs ECDSA for VANET Security

I am doing a project on Vehicular Ad-Hoc Network Security (VANET). The proposed scheme uses electronic signature as a means to authenticating the nodes. Most of the research papers I read suggested ...
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3answers
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Does HTTPS retrieval, among its other effects, sign a document? [duplicate]

Does HTTPS retrieval, among its other effects, sign a document? I'm asking in hopes of understanding in more specific details what TLS accomplishes. I will try to elaborate my question, as follows. ...
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229 views

Digital signature based authentication schema using two passwords

I'm working on an authentication system for a web based Bitcoin-related service. As part of the service, users do some less sensitive operations (mostly reading and sending various types of ...
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2answers
72 views

Attack Signatures books [closed]

I have an assignment to do for school which involves attack signatures (I have to do a service-specific IDS). Basically what I have to do is to generate signatures for some attacks with Metasploit on ...
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231 views

Digital Signature Software

What is the digital signature software? What it takes to digitally sign software? I'm using the Kaspersky antivírus and the software I wrote, in Delphi, is flagged by the antivirus software due to ...
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367 views

What popular online services allow passwordless authentication using digital signatures? [closed]

I am looking for web services that allow clients to authenticate using digital signatures. Especially with e-commerce and payments, clients generally authenticate using name and password (sometimes ...
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1answer
4k views

Certificate verified using two different paths

StartSSL has an intermediate certificate that they use to sign their EV certificates: sub.class4.server.ca.pem. This certificate's issuer is shown by openssl x509 to be /C=IL/O=StartCom ...
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4answers
144 views

Is it ok to send user's private key away, even if protected with a SSL channel? [duplicate]

I'm developing a webserver that performs digital signatures of (xml, pdf and office) documents and then validates those signatures. My idea is: an user puts its SmartCard and through a PIN, he gets ...
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935 views

Which mail clients support PGP/MIME - is there an overview? [closed]

Does anyone know if there is a current overview (I only found ones from before 2006) which MUAs (mail clients) do support PGP/MIME? I wonder whether there still exist issues like "Outlook Express ...
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713 views

Digital Signatures of XML, PDF and Office Documents on every platform

I'm trying to develop a website that performs digital signatures on client-side and then sent the signed document to the server-side. I want to do the signatures on client, due to the fact of not ...
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Is the digital declaration just an obscure proposal?

One professor from my university proposed me and some colleagues to work on a paper about the digital declaration (which is supposed to be better than the digital signature) for passing the subject. ...
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3answers
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Is it ok to send user's private key away, even if protected with a SSL channel?

I'm developing a webserver that performs digital signatures of (xml, pdf and office) documents and then validates those signatures. My idea is: an user puts its SmartCard and through a PIN, he gets ...
3
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1answer
492 views

GnuPG/KGpg Sign PGP Key - Sign User ID : What is the difference?

What is the difference between signing a user ID and a whole Key ? Which behavior is the best as to signing user IDs and Keys ? How and when to use "Local signatures" (non exportable) ? (I was told ...
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101 views

Digitally signed scripts as a way to thwart XSS

As a blanket approach to dealing with XSS attacks, rather than having to remember to escape user-generated code, is there a way to instruct the browser not to execute any script or script-function ...
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1answer
434 views

valid PDF signature without using hardware HSM or usb Token

I have a DMS system(alfresco) that needs to sign approx 50.000 valid signatures a year. The signing certificate needs to be acquired from one of the affiliated sub-CA's. So according to the Adobe CDS ...
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Reading older mails signed with a certificate that has meanwhile expired

A few years ago I have used S/MIME certs to sign (and encrypt) my mails. The reason for which I stopped signing was the following: My (class 2) cert was issued on Jan. 1st 2008 (just a sample). It ...
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Why do people still use/recommend MD5 if it is cracked since 1996?

It's still commonly recommended way of hashing passwords, even if it's insecurity had been proven in 1996 Therefore we suggest that in the future MD5 should no longer be implemented in ...
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142 views

How to modify a certificate using getTBSCertificate() method

I want to show that if I modify one bit or byte from a given X509 certificate the signature verification results false (because this modification results different hash value from the certificate). ...
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Internal code-signing certificate on Windows

I'm looking to improve defense-in-depth on a system, primarily by closing some holes in injected DLLs. Certain applications installed on the system cause helper DLLs (e.g. shell extensions, BHOs, ...
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How to sign & timestamp log or zip files?

I think I can easily sign the files however I also need a timestamp from 3rd party vendor. I want to digitally sign + stamp log files including DHCP & mail because of laws here. UPDATE: I found ...
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Digital signatures and truly validating what was actually agreed to

I am developing an application and part of signing up requires a user to sign a contract agreement of using the service. I have been reading around the subject for a few days, and I am fairly happy ...
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How are private keys handled in an enterprise?

We would like to start using digital signatures and possibly encryption for e-mails in our company. My knowledge of public-key cryptography is entirely theoretical with no practical experience. In ...
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1answer
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How online document signing services guarantee non-repudiation?

There is a number of services online like RightSignature or SignHub that will let you sign online legally binding documents. I understand how documents can be signed digitally and this can guarantee ...
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91 views

Proof of quantum safety of the Merkle signature scheme

The Wikipedia article about the Merkle signature scheme claims that it is very adjustable and resistant against quantum computing. What proof is there of this?
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Ideal cryptocurrency digital signature

What are the characteristics of the ideal digital signature for cryptocurrency transaction verification? The reason I ask is because this answer about bitcoin signatures describes a potential ...
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Is it possible to digitally sign information with a password?

I'm creating a cloud storage service and need to have the ability to provide reliable security for clients. In my previous question, I used a different schematic and said I would post a new question. ...
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1answer
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Signing session cookies

The Play Framework for Scala has support for signed session cookies. In the application configuration file is an "application secret" that is set as a secure random number when the application source ...
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Can a zero knowledge proof of voting be made using a trusted auth server (without client side crypto)?

Questions: Can one implement a secure voting system having all the features described below? e.g. without disclosing any individual's vote to the government server (or the third party), preserving ...
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6answers
254 views

Does an email signature increase security?

I'm using Thunderbird with Enigmail. It has both encrypt and sign options for sending PGP emails -- but why is an email signature needed? It just looks overkill to me! Alice and Bob can use PGP to ...
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How to detect authenticity Of Client and Server Certificate?

How its possible to detect authenticity Of Client and Server Certificate. For example, If server A has certificate and someone C stolen its certificate and send it to B then How we decide that it's ...
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4answers
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Evil certificate authority in public-key-infrastructure

Alice goes to the certificate authority (CA) and registers her public key for signature verification. She gets a certificate for this from the CA. Bob requests Alice' public signature verification key ...
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1answer
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What protection certificates would be required for an application that consists of setup, loading utility and main application?

Say we have an InnoSetup installer script, a native C++ QT files loading application and a .Net client application that we load/update each time and which is the main application. We load files via ...
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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 ...
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Subdomain-only SSL security/availability

CAcert and StartSSL both only validate domains whose TLD is owned by the requester. I have a few subdomains that come from places like freeDNS that I would like to run an SSL-secured server on. Are ...