Questions tagged [cryptography]

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

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How is the certificate encrypted?

I want to get an Apple CA certificate from the link https://setup.icloud.com/setup/qualify/cert?ver=P1.10.1 but I get an unclear file. How is it encrypted? Or how can you open it? i tried to save it ...
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How should eMMC RPMB shared keys be stored?

Storing data in the eMMC Replay Protected Memory Block (RPMB) requires use of a shared key. RPMB read/write operations utilize the shared key to generate a Hashed Message Authentication Code (HMAC). ...
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Cant we use md5 like hash algorithms to store big data?

i've read a paper about how hash algorithms word in general and i saw one strange thing. MD5 input length is unlimited and the output length are always the same so isn't that mean you can turn any ...
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How to do a clean installation of Windows 10 while keeping BitLocker enabled?

I didn't want to have to disable the bitlocker to format the PC, because that would definitely make it possible to recover data that has not been rewritten, and I value the security and privacy of my ...
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libcrypto.so.4 not found when using IOU on gns3

I have been trying to use a IOU image inside gns3 (with the rigth license). When starting the topology it says that the libcrypto.so.4 is not found. When doing ldd image_name_01.bin it says ...
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How to blacklist certain ciphers and key exchange algorithms in ssh and sshd

To get a list of all supported algorithms, I can run ssh -Q kex, which on my machine outputs diffie-hellman-group1-sha1 diffie-hellman-group14-sha1 diffie-hellman-group14-sha256 diffie-hellman-group16-...
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How to create certificate signed with RSAPSS using openssl command?

I tried https://gist.github.com/superseb/788a234647324b49ee5a56e07e3a91ac for commands, but getting following error in first command itself: sh-4.2$ openssl genpkey -algorithm rsa-pss -pkeyopt ...
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Why does ssh require the public key in order to delete a private key from the keychain?

If I have a private key file available locally, I can add it to ssh-agent like this: $ ssh-add key.private Identity added: key.private (key.private) Now I can see that key in the agent: $ ssh-add -l ...
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How can one disable supported crypto groups in Firefox's TLS support

I know how to enable/disable a particular cryptosuite in Firefox, with the settings like security.ssl3.rsa_des_ede3_sha in about:config. But I can't find how to do that with supported field groups, ...
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How to use b2sum in keyed mode?

Considering using Blake2 (perhaps b2sum) in conjunction to openssl dgst -sha512 -hmac $key but I don’t see an option to enable keyed mode.
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How to verify sender email address is really the one displayed?

.Hi experts, There are ways to fake the sender email address as I have read. Meaning that if you receive an email, then the"from" email address visible on the frontend in your email client can in ...
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How does a “passwd” and “adduser” command actually work on a LINUX OS?

(From a novice's point of view) The other day I was thinking about how a typical "passwd" command works in a LINUX OS. For example, when we type in "passwd", a prompt appears letting us type in our ...
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Generate entropy to create RSA keys

I was wondering on how I could make my server as most secure as possible. I use OpenSSH to connect to it, using RSA keys. However, something bothers me about that method: to generate the RSA keys, I ...
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Generating (pseudo) random numbers from a log file (eg. /var/log/maillog)

First: I really know that a true random number generator should have real random input, like something that is impossible to predict. Now, consider this: A busy mail-server can generate tens of ...
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What is C# RSACryptoServiceProvider doing under the hood when Encrypting using RSA?

When I drill down into the .Net source code I cannot find the code that actually runs when rsa.Encrypt is called, maybe it's running code within a DLL because I cannot find where the method is ...
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How can I run John Walker's ent program effectively on some data streams?

So the original ent program can be found here. The website doesn't give me a sufficient explanation, so I ask, how can I use this program effectively on Windows?
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Convert Openssl explicit ECC public key to named curve public key

While generating ECC keys using OpenSSL we can specify whether we want explicit public key info or named curve. Named Curve: openssl ecparam -name secp256r1 -genkey -noout -out my.key.pem Explicit ...
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unknown tag 26 encountered bouncy castle exception

unknown tag 26 encountered at org.bouncycastle.asn1.ASN1InputStream.buildObject(Unknown Source) at org.bouncycastle.asn1.ASN1InputStream.readObject(Unknown Source) at org.bouncycastle.asn1....
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How to generate different public keys for each user in a system using openssl in linux?

I want to generate private public key pairs for each user(multiple users) in the system. I have the below code to generate that RSA *rsa = RSA_new(); BIGNUM *bn = BN_new(); BN_set_word(...
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Is there a device or executable on Windows that can provide cryptographically secure random bytes via CMD or Powershell?

Essentially, I'm looking for the Windows equivalent of /dev/urandom on Linux. I know I can use Windows CNG via the C++ APIs, but no idea if there's an available (portable) method to access random ...
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Load key “ec256.pem”: invalid format is thrown on trying to generate public key from private key

I am trying to generate public/private key pair using ECDSA curve secp256k1 On generating public key from ec256.pem (private key) the following error is thrown "Load key "ec256.pem": invalid format" ...
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Encoding a PDF using matrix multiplication

I need to encode a patent application in a PDF file using matrix multiplication on Mathematica so I can save it on a cloud storage service so my partner can download the encoded file in Asia and ...
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How can I show installed CSP's on my Linux system without using the cpconfig util?

How can I show a list of installed Crypto Service Providers without using cpconfig or csptest? How can I check if there's a CSP on the current Linux system? The system is not mine and I'm told to ...
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What is the “TLS_GREASE_BA” cypher in TLS?

I've just ran a client test on SSL Labs Client Tester and my client reports as the favourite cipher suite a cypher named TLS_GREASE_BA with a null key length. What is this cipher suite supposed to do?...
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How to use MPIR with Visual Studio?

I am an academic and I need to develop some numerical algorithms which require functions from a package called MPIR http://mpir.org/downloads.html. I downloaded the 3.0.0 version and I am trying to ...
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HTTPS communication without requesting certificate

Is there a hack or the architecture of SSL/TLS allows communication with a Server without requesting it's certificate may be by pre downloading the certificate and installing it,The reason I'm asking ...
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CertUtil | How CertUtil -verifykeys works internally?

I have a CA certificate in Local Machine Certificate Store. When I run this command - enter code here certutil -verifyKeys gives Key "KEYNAME" verifies as the public key for Certificate "KEYNAME" ...
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GPG/SSH: Making a key a subkey after the fact

I'm still new to GPG, SSH, and whatnot, and I'm not sure what best practice is. I have a USB device capable of generating and holding GPG||SSH keys without them leaving the device. It also permits ...
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Can I use currency.js for commercial purposes? [closed]

I working on a cryptocurrency price tracker. I make use of the currency.js library. Can I use currency.js for commercial purposes?
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create private key from ECDSA public key

Public ECDSA Key Hex : 04d6597d465408e6e11264c116dd98b539740e802dc756d7eb88741696e20dfe7d3588695d2e7ad23cbf0aa056d42afada63036d66a1d9b97070dd6bc0c87ceb0d Public Address: ...
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Sapphire Nitro+ RX580 8GB Hynix Low hashrate?

I've got Sapphire Nitro+ RX580 8GB [Hynix memory] and it hashes on 21.9 mh/s out of the box without any overclocking or bios modding, as far as I know it should be higher around 24 mh/s, any ideas why?...
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gpg2 --edit-key addphoto / keytocard without password prompt

I am trying export subkeys to card for a keyring without any keyboard interaction using the command keytocard. This type of command is the same as addphoto as it requires to edit the keyring with --...
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gpg2 --quick-addkey without password prompt

I am trying generate in bash sub keys for a keyring without any keyboard interaction. I have tried several approach around what is mentioned here https://unix.stackexchange.com/questions/60213/gpg-...
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Windows 7 EFS, where are the FEK stored?

I feel confuse, I read from many technical doc from Microsoft and wiki. The FEK is generated for each file, and store in the file headers. But refer to this blog windows-7-how-to-use-cipher-exe-a-...
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How to get RSA Public Key and Private Key and get the modulus and exponent in plain text?

A requirement needs me to "Create or retrieve user’s RSA-OAEP key. There should be one public/private key pair for each user for a device" and send it to the server in this form: {"modulus":"...
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Are forms of device encryption still bulletproof enough for the average user? [closed]

Even after drive and BIOS encryption, can the data on a device (i.e. a laptop) still be accessed by the thief? (if he/she doesn't have access to the token or password or linked key generator). ...
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Can You Copy the RAM contents as-is to File-System on Windows [duplicate]

My question: Is it possible to copy the contents of RAM to the file-system? (Windows) Additionally, is it possible to copy the RAM contents for a specific process? Reason: This largely revolves ...
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How to Optimize a Dictionary / Word List?

I have a copy of a 4.09 GB wordlist / dictionary crackstation.txt. Just now the words and numbers are arranged in the usual order: 0123456789aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStT uUvVwWxXyYzZ ...
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Security: Is the Raspberry Pi really stateless?

The Raspberry Pi has become very popular. Because it is rather cheap and simple it could be an attractive device for people living in so called developing countries. However in many of these states ...
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1answer
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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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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 ...