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 SMIME differ from TLS, PGP, DMARC signature, or a Portal Encrypted email message in terms of legal non-repudiation?

I'm interested in protecting email messages from NSA-style snooping, but don't want to incur additional legal risk in doing so. In other words, does SMIME encryption and/or signing cause a given ...
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0answers
71 views

digitally signing a document [closed]

I've been asked to implement digital signatures for documents at work. I really need to read up more on the matter but several searches didn't make an obvious approach stand out. Main features I ...
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1answer
58 views

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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26 views

How digital certificate works? [duplicate]

I am trying to understand the digital certificate concept , but I am confused , Below goes my understanding & question, We are using Digital certificate because if Bob & Alice share their ...
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2answers
131 views

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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1answer
95 views

Algorithm to Transaction Data Signing

Transaction Data Signing I need an idea to develop a very secure algorithm to authenticate online operations using PHP in the server and an Android app in the user's device. What is the idea? The ...
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1answer
104 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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3answers
266 views

What part of the CSR is hashed in order to create its signature?

I'd like to change the CSR before it is transferred to the CA without going through the CSR creation process again. To do that I need to know how to calculate the signature of the CSR after I modified ...
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1answer
73 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
130 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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4answers
152 views

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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1answer
108 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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4answers
178 views

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 ...
2
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1answer
72 views

IKEv2: Why is it important “that each side sign the other side's nonce”

I am currently diging deep into the IKEv2 protocol. In the description of the Authentication (RFC5996, p. 48), the following statement is given: "It is critical to the security of the exchange that ...
2
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1answer
1k 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 ...
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1answer
248 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
66 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
122 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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3answers
69 views

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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0answers
152 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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1answer
99 views

Is long-term validity definitively corrupted upon TSA certificate revocation?

Suppose a document that was signed with a long-term signature (e.g. CAdES-A): D S T1 (D - document, S - signature, T1 - time-stamp created using a time-stamping certificate C1). If C1 appears in the ...
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2answers
51 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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1answer
145 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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1answer
2k 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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1answer
296 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 ...
2
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1answer
470 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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55 views

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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453 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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3answers
162 views

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 ...
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4answers
90 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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1answer
81 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 ...
6
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1answer
126 views

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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1answer
79 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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1answer
260 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 ...
3
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1answer
241 views

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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3answers
3k views

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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166 views

How to check executable code signing signatures?

How can I see all code signing signatures an executable has? I know that requests for a tool are usually considered as opinion based, but I really can't find one and I don't expect many answers. ...
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1answer
182 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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4answers
261 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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140 views

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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3answers
463 views

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 ...
3
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1answer
170 views

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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1answer
73 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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1answer
85 views

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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1answer
500 views

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 ...
9
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7answers
486 views

Authencity of information displayed on an untrusted device

Suppose I have a (bluetooth/usb) device which needs to displays information on an external pc/phone. Is there a simple and effective method to garantuee that the information displayed hasn't been ...
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1answer
215 views

DSA Generates different signatures with the same data [closed]

I'm using the example given in msdn article about the DSACryptoServiceProvider Class. The problem is that I get a different signature each time I run the code. I tried OpenSSL and didn't get this ...
3
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6answers
229 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 ...
3
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3answers
319 views

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 ...
3
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3answers
362 views

Is there an attack that can modify ciphertext while still allowing it to be decrypted?

Is there any way an encrypted file using AES-256 could be modified without alerting the file owner, ie., so it can still be decrypted with the same key? I know that without an initialization vector ...