Questions tagged [cryptography]

Cryptography is the collective term for algorithmic techniques used to secure data from unauthorized entities.

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Can an application that writes any data in a file be suspicious to an antivirus?

I am developing an application that, in order to work, needs to download data from the internet and store it in a .dat file. The problem is that some of that data is generated by other users. If a ...
Nathan Parker's user avatar
4 votes
1 answer
24k views

How to install openssl cryptographic library on Lubuntu

I'm trying to build cryptsetup 1.6.8 (or 1.7.0) from source using the openssl libraries instead of libgcrypt. ./configure --with-crypto_backend=openssl I did install libssl-dev but it still gives me ...
refex's user avatar
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Microsoft Certificate Store

I know that Microsoft Certificate store contains certificates with their corresponding private key. Now when using Microsoft certificate store, do we have to create it ? If yes then how ? or we get it ...
User1234's user avatar
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How am I to install the 32-bit version of Google's NaCl SDK?

I'm looking at playing with Google's Native Client SDK, so I've downloaded the tool to install it, installed pepper_46, and attempted to build the "getting started" project, and I was given the ...
Rob M's user avatar
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How to transcode AES encrypted files with AWS Elastic Transcoder

I want to upload my encrypted videos to S3 and use Elastic Transcoder to transcode them. This is what I'm currently doing and isn't working at all. I'm using openssl to encrypt my video files. The ...
Martijn's user avatar
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Corruption of a TrueCrypt file

Dear superuser people, this is my first question on the site so if I'm doing something wrong I apologize in advance :-) I've been using TrueCrypt for a few years now, not knowing they stopped ...
JinG's user avatar
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AES encryption with plain text key using bash openssl

I am trying to encrypt a string using AES CBC. The output of the online tool (http://aes.online-domain-tools.com/) and the bash openssl command do not match. Can anyone help me with what I am doing ...
Umang's user avatar
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Enable SCHANNEL Protocols in Windows Registry (Win7 & 2012R2) DisabledByDefault or Enabled?

I have enabled TLS 1.0/1.1/1.2 protocols on my local Win7 machine and 2012R2 server as well as disabled SSL 2.0/3.0 using the registry DWord value DisabledByDefault = 0 based on the following ...
xfitr2's user avatar
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Encrypting multiple drives on a multi-boot system

So I am building a new system and I want to fully encrypt it, problem is I am not really sure how since I never encrypted anything bigger than a folder or zip. The build includes a Samsung 850 EVO-...
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2 votes
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What's the difference between certificate and credentials?

What's the difference between digital certificate (e.g. .pem or .der files) and credentials (e.g. .pfx files)?
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How can I cryptographically verify that someone owns the website they claim to?

More specifically, can I get them to sign a string of text with their x509 private certificate and then I can verify it using the public cert used by the website in question? Perhaps I could supply ...
derrend's user avatar
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get x and y components of ec public key using openssl

I am generating a KeyPair for ECC from curve 'secp128r1' using openssl Steps I followed : first I generated a private key using the command openssl ecparam -genkey -name secp128r1 -noout -out ...
Dhruv Agarwal's user avatar
2 votes
0 answers
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3DES_CMAC encryption using online tools or OpenSSL

I have a smart card that claims that its mutual authentication is based on 3DES_CMAC algorithm. In the first step, the user sends a random number to the card and the card calculate the encrypted ...
Jean's user avatar
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6 votes
2 answers
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Beaglebone Black OpenSSl crypto acceleration

I'm running Debian Wheezy at my Beaglebone Black. Is OpenSSL using the hardware crypto accelerator by default? If no, how can I enable it?
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Cipher challenge [closed]

So I was recently challenged by someone to solve this cipher. I am not entirely sure which section of the stack exchange this belongs but I think that this is ok for superuser. Below is the cipher (...
Nicholas Summers's user avatar
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Looking for new way to create password [closed]

I tend to use same 2-3 passwords for all sites and want to change that but want to make sure I standardize my new approach as well. Looking at password hashing and I know very little other than what ...
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30 votes
1 answer
21k views

GnuPG / OpenGPG: Recovering public key from private key

I know that the public SSH key can be recovered from the private using ssh-keygen -y. How can a (deleted) public key be recovered from the private key in GPG (preferably in a way that is OpenGPG ...
leden's user avatar
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Can I use a "Microsoft Office" Digital ID / certificate to sign PDFs in Adobe Acrobat?

I've been needing to sign PDFs lately - fortunately everyone's been fine with me using a self-signed certificate, however I feel it's unprofessional. I'm looking for a personal certificate I can use ...
Dai's user avatar
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3 votes
2 answers
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gpg2 - no option to select aes block cipher and outdated use agent?

With OpenSSL, I can select a what type of block cipher to use for encrypting a file. For example, if I want to encrypt a file with AES256 CBC block cipher mode: openssl aes-256-cbc -a -salt -pass ...
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3 votes
0 answers
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Viewing and listing keys in MSCAPI CSP containers

I have a MSCAPI container created and hosted within a Windows Server 2003 environment. How do I use the command line to list keys and their details within the container onto the command line ?
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gpg keyserver duplicates signatures on my key

I created a new GPG key (rsa + rsa subkey), let's call it key1, and uploaded it to the keyserver. It has two uids. Later I signed this new key with another key (let's call it key2), and uploaded the ...
Kritzefitz's user avatar
1 vote
1 answer
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Is it possible to stream live audio/video safe from duplication/copying?

What I'd like to do is play an audio file exactly once and then it should not be possible to play it again. Is there such a file format or function? The scenarios I had was 1) Some famous music group ...
Niklas Rosencrantz's user avatar
1 vote
2 answers
922 views

Generate a public key certificate signed by CA with OpenSSL

I am working on a webservice that requires a signature in the sent and received messages. After sending a certificate request to the entity that will consume the webservice, they sent me (in addition ...
Zaid Malhis's user avatar
1 vote
1 answer
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How to get system-wide use of Intel's AES-NI acceleration with OpenSSL 0.9.8?

I found the following instructions to get Intel's contrib OpenSSL 0.9.8 engine code on some Westmere-based systems that we have: $ wget https://www.openssl.org/contrib/intel-accel-1.5.tar.gz $ tar -...
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1 vote
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CryptoLocker Ransomware. Can you recover files? [duplicate]

Today one of our PCs got infected with nasty CryptoLocker trojan crap. The PC was a Windows XP machine with up-to-date NOD32 a/v. As you probably know the virus encrypts your file with an 2048 bit ...
Ashtray's user avatar
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Enable GPU for cryptocurrency mining while running monitor off IGP?

Users in the cryptocurrency community usually solve this by either: -Using DVI-A or such to vga adaptor and make a dummy plug with resistors. However, all my hardware run with DVI-D. Vga adaptors don'...
Virosa's user avatar
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10 votes
3 answers
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OpenSSL ECDSA sign and verify file

I would like to sign and verify a pdf with elliptic curve. I got some code but it dosen't work. Create private key: openssl ecparam -genkey -name secp384r1 -noout -out private.pem Create public key:...
Michael's user avatar
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2 answers
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Is it possible to generate a file from a md5sum (or sha1 or such)?

Is it possible to recreate a file if you have the files md5sum? Or is it only possible through brute-force? Is it any differences between the different algorithms?
KingS's user avatar
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Why would one want to tag the computer where a key pair was made in a public key?

While trying to give an host a bit more of security, i decided to switch to SSH key's authentication. To do so i followed this guide, but something makes no sense in my mind. While the host is the ...
SOMN's user avatar
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29 votes
4 answers
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Human-readable dump of gpg public key

Is there some tool to write out the actual content of a GnuPG public key in a way a human can unserstand? I mean not only ascii-armor which a human can read and type, but something which really breaks ...
MvG's user avatar
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0 votes
2 answers
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Hand creating a password using website name as salt [closed]

A while ago I read a blog on a method of creating passwords. It was something along the lines of: 1) create a template password, with usual mix of chars, cases, etc. 2) use the website name the ...
James Kerr's user avatar
4 votes
1 answer
16k views

"line length exception" in hashcat (kali linux)

I've received this line: root:$1$25A116L54$7/IbiL1ZsUyPwYBx/zuNv/ and asked to crack the password. So, I created a crack.hash file and put the following in it: $1$25A116L54$7/IbiL1ZsUyPwYBx/zuNv/ ...
Amin Saqi's user avatar
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3 votes
1 answer
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SSHD HMAC Configuration

I have read and understand the posting from here, https://security.stackexchange.com/questions/39756/secure-configuration-of-ciphers-macs-kex-available-in-ssh. However, I would like to know what the /...
John's user avatar
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0 answers
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How to conduct a rolling data corruption test of a network connection?

I had problems installing some software packages on a Windows XP computer. I started troubleshooting the problem and at the end I decided to do a cryptographic test, and bingo! I had found the reason ...
Samir's user avatar
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8 votes
3 answers
2k views

How to install True Image on Windows XP?

I have 1 license of Acronis True Image 2011 for 1 PC. I had it previously installed on my Windows Vista machine and it was working. Now, I wanted to move it to a Windows XP machine, by uninstalling it ...
Samir's user avatar
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11 votes
2 answers
10k views

How can I use GnuPG with ECDSA keys?

I'd like to generate an ECDSA (rather than RSA, DSA, or ElGamal) key using GnuPG, and use it as I might otherwise use an OpenPGP-compatible master key. I've read that gpg2has support for ECDSA keys, ...
flamsmark's user avatar
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3 answers
108 views

Is it a good idea to use a long password that contains patterns? [closed]

Let's say one wants to encrypt a file using a passphrase (not a key), gpg can do that. Assuming a short passphrase, does it make sense to make use of a longer passphrase that is the short one ...
AnonymousLurker's user avatar
1 vote
2 answers
5k views

Openssl decrypt from encrypted text from command issue

I am using following command to decrypt an base64 string. openssl enc -in ciphertext -out binarytext -d -a openssl rsautl -decrypt -in binarytext -out plaintext -inkey private.pem I am facing an ...
Javad Shareef's user avatar
13 votes
3 answers
47k views

Why are there so many files in C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys

I am running out of disk space on C:-drive. We see many (millions of) files in C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys What are these files ? Why are so many files created? How can we ...
user avatar
7 votes
1 answer
2k views

Vim no longer prompts for encryption key when reading encrypted file; why not, and how can I get this restored?

I recently began using Vim to encrypt text files (by using the :X command and entering an encryption key at the prompt). As documented, Vim then prompts for that key when I reopen the file and ...
Andy Mo's user avatar
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Computing Number of Bits in Public Key

I am working with DKIM and trying to compute the public key size of some DKIM signatures. I know from tools that Gmail's is now 2048, but how could I have figured this out myself (i.e., what exact ...
eb80's user avatar
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7 votes
2 answers
4k views

how to verify the trust path to a gpg key?

I want to check whether the gpg key used by Julien Danjou for his emacs snapshot repository can be trusted. There are many trust paths from my key to Juliens key. But I can't believe that there ...
Thomas Koch's user avatar
1 vote
1 answer
712 views

How to open a LUKS, OTFE .vol?

I feel like this is a dumb question, but I can't find the answer anywhere. I have a .vol, LUKS/OTFE. I know the password. How can I open it? This should be simple, but the closest answer I've ...
rm-vanda's user avatar
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6 votes
2 answers
3k views

What is id_rsa.keystore?

In my .ssh directory I have the following files - drwx------ 2 rohit rohit 4096 Jun 22 03:34 ./ drwxr-xr-x 62 rohit rohit 4096 Jun 22 11:16 ../ -rw-r--r-- 1 rohit rohit 402 May 25 15:19 ...
Rohit Agarwal's user avatar
1 vote
1 answer
2k views

How to encrypt email with recipient's key?

I need to send an encrypted email to someone who has published his key. He doesn't have mine, so instead of encrypting the email with my private key as usual, I think I have to use his public key. I'...
HappyDeveloper's user avatar
1 vote
1 answer
538 views

How many guesses per second are possible against an encrypted disk? [closed]

I understand that guesses per second depends on the hardware and the encryption algorithm, so I don't expect an absolute number as answer. For example, with an average machine you can make a lot (...
HappyDeveloper's user avatar
0 votes
1 answer
428 views

per-host-pair cryptographic keys on a network

Got a homework question here that I have been staring at for a while. I am being asked how many keys will exist in a network of 'n' number of nodes with keys being distributed on a per-host-pair ...
Stephen R's user avatar
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1 answer
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Creating and evaluating digital signed signatures for authentication etc

This question is triggered by an email from Microsoft this morning about a security bulletin. It started with -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 and ended with a PGP signature. I've ...
Cyberherbalist's user avatar
1 vote
1 answer
326 views

Is Data Object on openPGP smartcard v2 encrypted?

Currently I thinking about on-the-fly disk encryption using Truecrypt/dmcrypt LUKS with key stored on smartcard. I would like to use openPGP v2 smart card, respectively GPF Cryptostick which is based ...
Ency's user avatar
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1 vote
2 answers
448 views

Encrypt a file without common tools [closed]

I am guessing this probably has a really long answer, so feel free to give a little explanation, with a link to a helpful article, tutorial or w.e How can I encrypt a file without using one of those ...
FALL3N's user avatar
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