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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Parsing a PKCS7 detached signature hash

I'm trying to manually verify signatures of Apple iOS Passbook files, which are PKCS #7 detached signatures of the RSA key of the Apple developer who created the file. Which means there's a file ...
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222 views

Is the `ssh-agent`'s DSA signature deterministic?

In my hopes to use ssh-agent to generate a signature as password I implicitly assumed a deterministic signature. DSA is however supposed to take random value k for signing. However that randomness is ...
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506 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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750 views

How to verify the signature in an iOS Passbook pass?

The Passbook application in the new iOS6 keeps track of movie tickets, coupons, and other 'passes' for you, and the passes themselves are loaded onto the user's device via file packages with the ...
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rsa encrypted hash == rsa signature

$ echo -n "1327943823" > test_ok.txt $ openssl dgst -sha1 -binary -out test_ok.sha1 test_ok.txt $ echo "GURbsl4CFPCG83RCZxsEpoRleXicXQhH1OC4Fk77b7EMj2g8aHUhD/L+sm ...
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Why not RSA-encrypt the entire document?

I have recently learned of a way for person B to verify that a document sent from person A is indeed from person A. Person A gives Person B his public RSA key. This must be done reliably. Person A ...
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2answers
865 views

Revoked certificate validation using past times

I'm working on XAdES implementation for Java, as such I require cryptographic implementation to be able to verify certificates in the past. Unfortunately I have problems verifying revoked ...
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224 views

Is there any security value of creatively naming folders containing sensitive files?

A friend of mine asked me if he could sign his tax returns without printing them out. While helping him, he insisted on naming the folder containing images of his signature and initials a completely ...
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210 views

Verifying Authenticode signed executables and DLLs using OpenSSL API [closed]

I have installed openssl and now the rsa_test.c is running fine. What I want to do is: Open any exe or dll digital certificate. Extract the Thumbprint and PublicKey. The public key contains the ...
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531 views

Distributed XAdES-X and XAdES-A signatures over multiple documents

As the standard is not completely clear in this matter, I'm trying to found out if the XAdES standard (ETSI TS 101 903 v1.4.2) describes distributed case in which the SigAndRefsTimeStamp element or ...
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161 views

How does a code signing vender charge for creating certificate chains?

I have a question about creating digital signatures for pdf files. I want to have a certificate for my company and have children certificates as many as the number of company's employees who can ...
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2answers
288 views

Reusing HMAC state for multiple messages

I have a secret key k and message m. I send m || HMAC(m, k) to some other party, who can verify the integrity of m, assuming that they know k. Suppose I have multiple messages m1, m2, and so on. ...
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800 views

Digital Signature and Verification?

AFAIK , When Alice wants to write a message to Bob -- she uses Bob's public key and encrypt the message - and then Bob - using his private key - use to decrypt it. So public key is used to decrypt ...
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1answer
77 views

Standards for CA cert revocation and time-constrained cryptographic algorithm parameters

I'm working on software that will be in use for foreseeable future (15 years+) that will need to validate XAdES-A signatures (long term archival, similar to PAdES-A, but for XML). That means, it will ...
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2answers
683 views

What are the real-time applications of long term digital signature with timestamp

I want to know the real time applications that uses digital signatures with timestamps. Specially I am interested to know the applications where we can trust an old signed document which is now ...
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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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2answers
794 views

Signed request vs HTTP digest auth for API authentication?

By signed request I mean something like this (simplified example): Client creates a sig in his request: $sig = hash('sha256', $api_key.$data); which generates 7409ur0k0asidjko2j for example. He then ...
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3answers
521 views

Can signing too much compromise a private key?

Can a collection of many messages signed with the same private key be abused to either forge signatures so some (but not all possible) messages, or even worse to reconstruct that private key with less ...
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1answer
243 views

Can I export my digital certificate to this emtec usb

It is said here http://www.emtec-international.com/sites/default/files/s530_aes_en_0.pdf 2048 bit RSA module: ready for PKI application SHA256 data hashing: ready for digital signature Does it ...
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What is the difference between an electronic signature and a digital signature

From Wikipedia: An electronic signature, or e-signature, is any electronic means that indicates either that a person adopts the contents of an electronic message, or more broadly that the ...
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1answer
277 views

Signature and Timestamp for Long Term Document Archival Question

I have a PDF document intended for long-term (many years, maybe decades) archival which I would like to digitally sign with my personal certificate to ensure its integrity. As far as I understand, I ...
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1answer
431 views

Purpose and Uses of Root SSL Certificates

I'm trying to wrap my head around the technical inner-workings of SSL and one of the last things I'm choking with is the concept of "root" SSL certificates (as opposed to "non-root"?!?). When and ...
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2answers
447 views

Request/Creating a Code Signing Certificate

I have need for a code signing certificate which is trusted by a CA in the windows domain. How do I request/create this certificate? Do I have to request a code signing certificate on the ...
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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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Using digital signatures to identify users

Consider the following requirement: Bob should be able to verify that a payment request came from Alice. The above is in simple terms the basic idea, however, in reality Alice would be user A of ...
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605 views

Digital signature with partial recovery

I'm having problems understanding what is meant by "digital signature with partial recovery". I found from Google that digital signature with recovery should mean that the message is recoverable from ...
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3answers
340 views

Why do credit cards not use digital certificates?

Asymmetric encryption and digital certificates are used all over in the IT world to verify authenticity and prevent forgeries. And it works great. Why do credit cards not use some form of ...
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517 views

Best Practices for Storing Digital Certificate

I'm building an application where certain sensitive files need to be digitally signed before being stored in the file system using ASN.1 encoding, so they can be verified against a digital certificate ...
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2answers
633 views

Time needed to generate an RSA signature of a document

How does the length of the RSA key and the size of the document affect the time it takes to sign a document using SHA-1 and RSA? I used CrypTool to check it, but the time does not appear to be larger ...
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Does GPG key expiration add to security?

I've created a new GPG 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 or ...
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What is the actual value of a certificate fingerprint?

In a x509 digital certificate there is a "certificate fingerprint" section. It contains md5, sha1 and sha256. How are these obtained, and during the SSL connection, how are these values checked for?
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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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324 views

Does signing my e-mail with DKIM imply non-repudiation for all my users?

Since a few weeks I have set up my google apps domain to use DKIM for all outgoing mail. Does this mean that everyone that is in possession of a copy of the message can verify that it really ...
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635 views

DRY API Authentication Design Between Services

I am creating an API service that is going to require authentication. this will be the first part of a project that will include a front-end service for my website, and also open up the api for 3rd ...
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677 views

Enforce Code/Script Signing

I have both a couple of X.509 Code Signing certificates and a GPG keypair that I can use to sign against code I run on my VPS. Every now and again I write code for iOS, OS X and Windows and always ...
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1answer
955 views

encode der with openssl

When you issue openssl dgst -sign key <file it follows the PKCS#1 standard to generate a digital signature. hash file with some hash digest function encode the hashed value in DER format, ...
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A “good enough” digital signature, with short key

In my application, I want to hide debug feature behind a password. I don't want the password to be easily known by issuing strings executable, so I want to rely on digital signature. We want Debbie ...
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Can I use a private key as a public key and vice versa?

I have code to encrypt data using a public key and decrypt it using a private key. This is useful when a client wants to send data to a server and know that only the server can decrypt it. But say I ...
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Are the SSL Digital Security Certificates based on Kerberos Network Security Protocol

I just want to know if digital certificates use the kerberos session key algorithm.
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19k views

How to use OpenSSL generated keys in Java?

I have my pair of Public and Private keys and my certificate. Those where created in OpenSSL (why? because I was asked to do it in OpenSSL). Now I want to use those things to make a Java app that ...
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2answers
245 views

security and the well constructed Qt plugin

"All you'd have to do is build a plugin and you could completely pwn the software." I'm building an application using plugins. I think all you have to do is build a plugin and copy it into the ...
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462 views

OpenPGP Encryption / Decryption Process Using GnuPG

I want to know if my method of encryption can ensure the security of my data if my database was hacked as well as the authenticity of the data I am decrypting. I am using GnuPG's implementation of the ...
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openssl verify signature

For S/MIME, I now know I can verify PKCS#7 detached signatures with: openssl smime -verify -in detachedsign.pem -content content.txt But what about non-MIME messages? So if I sign the message ...
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2answers
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Null content digitally signed message

IA technical specification I'm following requires me to send: The Digital Signature must be in the form of a null content Digitally Signed message (i.e. a PKCS#7 object containing the signature ...
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5answers
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What does “key with length of x bits” mean?

I'd like to know what it means to say "the cryptosystem C uses keys with a length of x bits". I do not understand what the bits length means... doesn't it depend on the encoding? The same word encodes ...
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2answers
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Digital Certificate deployment: using two certs for each user?

At a large enterprise environment I have come across a deployment approach for Digital Certificates where each user is issued two (2) key pairs: One for signing documents, emails, etc. that is ...
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4answers
103 views

Securely signing a container package

I have a desktop application that uses a kind of package format to load a blob and do something with it. To ensure the authenticity of the blob, I would like to add a digital signature. I researched ...
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Why are hand-written signatures still so commonly used?

Why are hand-written signatures still so commonly used? Can they actually prove anything? Two assumptions: If anyone wants to forge my signature I'm sure they will be able to do it. Even my own ...
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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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How to Get and Set Digital Signatures with FDA 21 CFR Part 11 Standards

How do I get and set digital signatures with the 21 CFR part 11 standards as defined by the Food&Drug Administration of the USA?