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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Can a signed downloaded file be securely verified if you only control the private key and the download/verification algorithm?

I'm designing the update procedure for IP Camera's. I'm wondering if my current design is secure enough. I have a binary file that I want to get to a device. I make a hash of this binary file and ...
4
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2answers
108 views

Is it possible and does it make sense to sign an E-mail with PGP and S/MIME?

After some research without any answer to my question, if it's possible and does it make sense to sign an E-mail with PGP and s/mime (?), I'm hoping to get an answer here. I know that, PGP and S/MIME ...
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1answer
32 views

I want to know about all the specifications of a cell phone when it enters into particular area [closed]

I want to produce a signal such that when a cell phone enters that area, I must get all the specifications of that device. Can I do it? Which signal is good?
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1answer
15 views

Applications of the message recovery schemes [closed]

What are the applications of the message recovery in the digital signature schemes?
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14 views

OpenSSL 0.9.8zc -> 0.9.8zd “broke” my certificates. [migrated]

I have a self-signed certificate (and CA) created on a Mac using OpenSSL 0.9.8zc. I use the certificate to secure connection to my svn server. With the latest OS X update, OpenSSL was updated to ...
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1answer
17 views

How do I verify a GPG signature attached for a cleartext email using the gpg command line?

I received an email in cleartext from someone with a signature.asc attached. Looking at the raw source for the email, it was sent with Apple Mail + GPGMail. Reading the message in Thunderbird + ...
2
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1answer
59 views

Use the server's key to digitally sign the HTML content it delivered?

Is there any way to prove that a HTML page was delivered to my browser, and not modified in any way, after it was delivered over TLS? I need to prove integrity, and authenticity of the sender, ...
2
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1answer
115 views

Generating secret keys with secret keys

Hydra is a secretive organization. It is comprised of several Directors at the top, and many Agents underneath them. A Director sends Agents on secret missions. During these missions, communication ...
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0answers
26 views

PKCS#7 signed data structure in signed PDF document

Is it mandatory to include PKCS#7 data (OID 1.2.840.113549.1.7.1) octet string into the sequence of PKCS#7 signed data? I mean if you want to sign PDF, you are basically adding PKCS#7 container ...
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1answer
27 views

Signing the Recovery Partition

Do any computer manufacturers sign (DSA, or just publishing a hash) their recovery partitions so that I can be sure that these bits are authentic? I'd like to buy a second-hand computer and reduce ...
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1answer
33 views

Subject verification of certificates

Suppose H has taken C’s certificate and manually changed the subject information in C’s certificate from C to H. Would this modification be detected by A during the certificate verification process?
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2answers
152 views

Untraceable Digital Cash?

I have read some articles regarding digital cash with untraceable(Here). Their protocol is provided below Withdrawal: Alice creates an electronic coin and blinds it. Alice sends the blinded ...
2
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2answers
67 views

Is HTTPS required for PCI Compliance when downloading desktop software patches, if no PII is transmitted, and content is digitally signed + verified?

We have a desktop app that downloads patch content via HTTP. The content is digitally signed and verified by client software after download. Is HTTPS required to achieve PCI compliance if: No PII ...
3
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1answer
60 views

Standard to represent digital signature on paper

Users are making a deal using the website. Website generated PDF file (something like contract or report). Users perform digital signing of this file (analogous to hand-written signature on paper ...
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1answer
34 views

Advantage of Group signing over single signing

As i known signing is used to ensure integrity and authenticity of sender. What is the advantage of group digital signing over individual signing. Can anyone explain using a scenario?
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0answers
38 views

Is LTV in a pdf required if it has a trusted timestamp and the Verification Authority is guaranteed to remain active? [closed]

I have successfully managed to add valid "qualified digital signatures" using a USB token to the PDFs generated by our web application through TCPDF. I am now wondering if I should try to add a ...
3
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1answer
62 views

Does a browser have to make multiple requests to verify an SSL certificate chain?

I've learned that SSL certificates can be chained, and the browser will use the issuer's public key to verify the issuer's signature. I have read this article, which has a very helpful diagram, but it ...
3
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1answer
73 views

Does PKCS #7 (CMS) add assurance to an email if a CRL/OCSP response is included, then revoked?

Suppose I issue a signing certificate in January, and have a daily CRL issued (expires in 1 day) to verify the validity of that signature. Then sometime in July I need to revoke that certificate. My ...
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1answer
62 views

Diffie Hellman and exchange of public key for signature

Let's assume an insecure channel. Is it safe to exchange Alice & Bob public keys first then apply them to sign communications during the DH process? (then encrypt+sign all future communications)? ...
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1answer
49 views

how to extract a valid digital certificate and put it on other program

I am working on this matter as a graduate, but I need some help. how can extract a valid digital certificate to put it on other program? can I put a digital certificate on other executables and be ...
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1answer
60 views

Can a Bitcoin miner generate SHA2 hashes on arbitrary data?

I'm not asking about bitcoin's design...but am interested in the hashing capacity of a bitcoin miner. To be short: do bitcoin miners(or some of them) accept customizable inputs and hash them in ...
1
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1answer
47 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 ...
2
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2answers
92 views

Can CA issue a certificate without CSR?

My question is if the CA can generate a private/public keypair on behalf of the requestor and sign it with its own private key? Is there any standard way or protocol to distribute such a ...
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1answer
77 views

Rest WebService with signed requests in Java

I'm currently implementing a rest web service with Spring+Java+Tomcat and a cmd client to access it. The most important requirement is to restrict the usage to authenticated users - encryption isn't ...
2
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2answers
65 views

Using digital certificates in digital signatures

Please could anybody explain to me how certificates are used with digital signatures? I understand difference between certificates and signatures. It is clear. Digital certificates are used to ...
4
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1answer
35 views

Mail Signing Certificate – What are the impacts when revocated?

Suppose I open a signed mail on 1st January 2000, signature is OK. What about this two cases : 1) If next CRL is to be published one week later, I found it strange that it is “probably” valid until ...
2
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1answer
32 views

What is the ideal HMAC message format if message is an array?

I'm using HMAC exactly as intended to verify the integrity of a message. However, the message is really an associative array (or a hash). Since this will be done on various platforms (within and ...
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1answer
51 views

Keeping signatures valid even after the private key has been compromised

If I understand the topic of digital signatures correctly, you sign a message via hashing+encrypting it using your private key. Then, if a private key is compromised by an attacker, she could sign ...
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0answers
24 views

Guidance on Login using Digital Signature DSC (PKCS12 and x509 certificate)

I'm interesting in exploring possibility to authenticate user using their Digital Certificate. The methodology is to first register the DSC from the user and keep their Public key along with Serial ...
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1answer
60 views

Signature scheme using RSA and SHA512

What do you think about this signature scheme using RSA with 4096 bit keys? Being R pseudorandom padding, fixed length (4096 - 512 bits): RSApriv(R || SHA512(M)) I know that it's not as secure as ...
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0answers
36 views

Sign java jars for security [closed]

We have an enterprise system that utilizes many in house jars, java applications, to run on a centos 7 linux system. How do I go about achieving the following in order of importance: Only signed ...
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1answer
55 views

Digital signatures and weak hash functions

There was this question in last year's exam. The teacher claims that answer b) (in boldface below) is correct. Attacks are constantly being performed on digital signatures which use weak hash ...
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2answers
99 views

Verify digital signature without key public key in signature

When receiving emails, I sometimes see the following: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I found an integer overflow in PHP, in the conversation of dates to "Julian Day Count" function. ...
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1answer
119 views

If you can break this authentication system then you can break into my house

I'll preface this by saying I know approximately 0 about cyber-sec I've made a server that will allow smart phones to act as a remote control for my house (eg turn lights on/off and unlock doors). ...
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0answers
14 views

Why do PGP Keys have expiration dates? [duplicate]

I read a tutorial to get started with PGP and so far I understand the importance and the difference between encryption, decryption, signing, and verifying. However, I don't understand why a key has ...
1
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1answer
114 views

Server-based PDF Signing using HSM

I have some question about server side pdf signing using network-attached hardware security module. my first question is: what is PDF Signing Certificate? Certificates are public keys, how a ...
3
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1answer
60 views

What encryption and signature systems (don't?) allow for plausible deniability of the OP's key being used?

I need to prevent Mallory from blindly matching encryption and signing keys to messages Hypothetical scenario: A user creates a public key An encrypted or signed payload exists. With only public ...
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1answer
64 views

Multi-Function SSL Digital Certificate

Is there a problem with using a single SSL certificate for both SSL/TLS/HTTPS communication as well as to sign (external) digital timestamp certificates? Other than the obvious: if one key is ...
2
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2answers
82 views

Public key authentication: what gets signed?

I've just started reading about SSH and how it's used for authentication. From this website, it says: The private key is able to generate signatures. A signature created using your private key ...
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2answers
77 views

Installing and updating a CA certificate on a client

I am trying to implement a system where a client can download application packages from a server to install/update them on the client. I suppose that the client is something like a platform on an ...
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1answer
51 views

Algorithms for transaction authentication

It's unclear to me how transaction signing and transaction authentication work. Industrial solutions use both symmetric and asymmetric algorithms to compute the signature. What does RSA add the ...
2
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1answer
58 views

Are there theoretical attacks against ECC Digital Signatures?

I was asked to do a research about attacks on various digital signature schemes. There is one thing that bothers me for which I could not find a direct answer. For digital signatures that are based ...
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2answers
80 views

SHA1 - S/MIME and CRL validity after deprecation?

In an internal PKI using SHA1 for hashing, will S/MIME signature and CRL/ARL signature be considered invalid in the next few years (SHA1 Deprecation) ? End certificates can be revoked, CA ...
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2answers
55 views

Certificates - What about signing again Intermediate CA certificates?

I an thinking about this issue and it is hard to estimate technical impacts. For any relevant reasons, one want to modify one the x509 field of an intermediate CA. This intermediate CA was signed by ...
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2answers
263 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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1answer
92 views

PKI - Security concerns when changing a certificate hash algorithm

Suppose I want to change the hash algorithm used for a certificate signature (ex: SHA1 to SHA2). Is it better to revoke the previous certificate and issue a new one with expected hash algorithm ? Or ...
3
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3answers
200 views

Corporate PKI - SHA1 deprecation

Here is the context. Suppose you have a corporate PKI with : AC_Root (offline in safe store - SHA1 signature) SubRootA and SubrootB (offline in safe store - SHA1 signature) SubSubRootC, SubSubRootD, ...
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1answer
181 views

Is there a way to verify a signed XML in Java

.NET has this great way to sign and then verify the signature of an XML file. Is there a way in Java to verify an XML file that .NET has signed this way? thanks - dave
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2answers
47 views

TLS - Are signatures still needed?

The story: I'm currently writing a web service that allows for communications to be made remotely via TCP/IP. I first thought about signing each packet using HMAC-SHA1 with a password, appending the ...
2
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1answer
52 views

What is 0xXXXXXXXX.asc.sig and how can I generate this?

When I am exchanging PGP keys with someone, I receive the regular 0xXXXXXXXX.asc file and regularly receive a file called 0xXXXXXXXX.asc.sig. What is this file? How can I generate one and send it ...