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Questions tagged [cryptography]

Cryptography is the practice and study of logical means used to achieve information confidentiality, integrity and authenticity. It covers, among other things, encryption (making some data unreadable except for those who know a given secret element, called a key), data hashing (in particular for password storage) and digital signatures (provable integrity and authenticity with non-repudiation).

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Why does ε-differential privacy protects the subset of 1/ε edges in terms of graphs?

In the book The Algorithmic Foundations of Differential Privacy by Cynthia Dwork, Aaron Roth on page 24, databases that take the form of graphs are discussed. We could on the other hand consider ...
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Is it safe to encrypt some data which contains a uuid while also sending the uuid as metadata?

I have a json data-interchange format where I send messages like the following: { "revision": { "client": "f0ede1da-7314-4e59-99f7-a3a71dcab11f", patch: ["hello world", 0] }, "client": "f0ede1da-...
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What does “probabilistic algorithm with random tape” mean?

I am new to the study of cryptography, and when reading papers they often mention that "probabilistic algorithm G with random tape w ...". What does it mean by "random tape w"? I mean why it does is ...
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Key management in cloud datacenters

In terms of infrastructure, how do Cloud providers (organizations providing SaaS, PaaS, or IaaS via the cloud) manage keys and cryptography? From my understanding, "private" datacenters tend to ...
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bcrypt.checkpw() returning true for different salt+hash

new user here. I've tried searching for an answer but I don't think I know the correct terms to search for. I've tried things like "bcrypt same password different hash" but can't find an answer to my ...
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Secure Personal Information for Restful API

I need to implement a web application for user to update personal information. It consists of a page listing masked personal information and then a button which allows user to edit & update them. ...
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iOS Security Architecture-Encryption Keys

As per iOS Security 12.1 documentation(Page-15), there are individual UID and GID for each processing unit i.e AP(Application Processor) and Secure Enclave. The application processor and Secure ...
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Secure Exchange Rate for Restful API

I need to implement a web application for user to exchange money. The application needs to invoke API #1 to retrieve exchange rate and show it on the screen for confirmation. And then invoke another ...
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What makes Random Number Generators so fragile?

It seems to me that a hardware component which generates random numbers is extremely simple - just measure tiny vibrations in the hardware with a sensor, right? Maybe I'm wrong but it seems like if ...
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284 views

How to verify a private key has not been compromised?

I have a machine with a process that signs code for users running 24/7 (encrypting the key is not possible), which will be protected as well as possible. Is there a way to set things up such that I ...
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Encrypting then Base64 Encoding

I notice online encryption tools encrypt the plaintext and output the ciphertext in base64 format. Why is ciphertext outputted in base64 format? Can the ciphertext be outputted in binary format?
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Is there any advantage to splitting a password?

I've been reading about the LANMAN (LM) hash and I'm curious about a particular part of the algorithm. The LM hash is computed as follows: The user’s ASCII password is converted to uppercase. This ...
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How to determine what type of encoding/encryption has been used?

Is there a way to find what type of encryption/encoding is being used? For example, I am testing a web application which stores the password in the database in an encrypted format (WeJcFMQ/8+8QJ/w0hHh+...
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Is it safe to use a passphrase to seed fernet key generation?

I have a cluster deployment that depends on a Fernet Key to secure some data. The deployment script generates the key with: FERNET_KEY=$(python -c "from cryptography.fernet import Fernet; k = Fernet....
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What string encoding options are there besides xor? [closed]

When attempting to obfuscate strings in a modern program, xor is probably the most common option. By this I mean running each char of a string through a function which xors the char with some given ...
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One GPG key with multiple user identities for my career?

I am trying to work out what is the best approach for managing GPG keys over my career when I change jobs. My understanding is that there are two ways this could be done: Have one main/master GPG ...
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Are there any “real world” implementations of secret-sharing encryption schemes?

Imagine something like TrueCrypt where user A can decrypt his files, or any 3 of the 10 directors in his organization can decrypt user A's files. As I understand it this is similar to the way the ...
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What is a secure way to encrypt critical secrets for a person likely to be individually targeted [closed]

I read several guides and Stackexchange answers, but the more I know, the more I realise how much I don't know. What I learnt is that details of implementation matter and that most popular tools do ...
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Password Hashing: add salt + pepper or is salt enough?

Please Note: I'm aware that the proper method for secure password storage hashing is either scrypt or bcrypt. This question isn't for implementation in actual software, it's for my own understanding. ...
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Is it safe to use Orbot with the normal Firefox browser on Android

I noticed that when using Orbots "VPN Mode" that my normal Firefox browser works fine and when I visit check.torproject.org it says I'm connected even though I'm not using the Tor Browser specifically....
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Is it possible to make a crypto wallet software secure without forcing users to encrypt keys with a strong password?

I'm creating a mobile software crypto wallet. I'm not an expert, but to my understanding, no software crypto wallet is 100% secure, as it can be reverse engineered so that the private keys are exposed....
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Is sending password to user email secure?

How secure is sending passwords through email to a user, since email isn't secured by HTTPS. What is the best way to secure it? Should i use encryption?
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Is there any open source SDK for implementing a KMIP server?

Is there any reputable open source SDK for implementing an OASIS Key Management Interoperability Protocol (KMIP) server?
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TDE - Encrypting different rows with different keys

My question is in general but related to Oracle DB. I have a single table with different companies as rows. Each row has company id and company registration number. I would like to encrypt company ...
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Is Telegram secure?

There is a new WhatsApp-killer application called Telegram. They said that it's open source and that it has a more secure encryption. But they store all the messages in their servers and WhatsApp ...
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Advice on Site-to-Site VPN in China and protecting Intellectual Property

I know the title is an oxymoron, but our manufacturer is based in China, so I need to get as much information as possible so that management are aware of the risk/s and make this as air tight as ...
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Proving that a certain site had given page at certain time [duplicate]

Lets someone opens https://foo.com and saves the page using "save page as". Is there any way to prove later that the locally saved files have not been altered assuming that we trust the server public ...
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Is pressing random keys a secure way to seed a key generator?

There's a couple of programs that I've been using recently that ask you to type random keys as a source of randomness to seed an RNG for key generation. Is this considered a good practice still, or ...
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Where does last 4 bytes of hmac go in wpa2 mic?

The wpa2 mic is a 16 bytes array which is built by Hmac(sha1) ,But the Hmac(sha1) returns 20 bytes array. So where does that 4 bytes go?
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Shared Secret, is it a public key or a private key?

Reading the Diffie-Hellman non mathematical explanation i found that some mathematical operations are performed on private-key and the recipient's public key to generate a "shared secret" on both ends ...
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1answer
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Choosing Key and IV in AES-256

I am working on a real-life project for a firm. I have to encrypt data using AES 256 as per specification. I want to know how are the key and IV are really chosen in real world projects. /dev/urandom ...
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Is it safe to include the IV at the end of a hash?

I have a PHP function I have written that uses a 64 bit binary string and a random initialization vector to encode data using the following basic principal: $encrypted = openssl_encrypt($...
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Convert python-pkcs11.types.PrivateKey to PrivateKeyInfo or PrivateKey

I'm building a CertificateListBuilder but it requires the python-pkcs11.types.PrivateKey to be an instance of asn1crypto.keys.PrivateKeyInfo or oscrypto.asymmetric.PrivateKey. How to do it? Is it ...
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What makes SoftHSM more security than other software solutions such as OpenSSL? [closed]

I see many people using softhsm just for encryption / decryption rather than using openssl.When I ask people they reply softhsm is more secure. Can anyone say in what ways softhsm is more secure.
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How does the digital signature verification process work?

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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Cipher that does not give confirmation whether decryption is successful

I was reading this question where the author wanted to know whether layered encryption would be better than a long password. The answers to this question all said the same thing: It would be easier ...
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Know the setting used in creating key pair in GNUPG4Win version 3.15

I am using GNUpg4Win version 3.15. For the last few hours I am trying to figure out what default settings are used for Cipher and Hash during key generation. Basically I want to use AES-128, 3DES ...
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Does using both a counter and a random nonce make sense for the purpose of reducing the likelihood of replay attacks?

I am aware that using a counter or a random value are both acceptable ways of generating nonces, depending on the circumstances. The tradeoff with using a counter is the necessity to keep state and ...
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Digital Signature is not valid

I recently received a digital signed email from a friend and the certificate is issued by COMODO RSA Client Authentication and Secure Email. My problem is the thunderbird detect it as a "Not Valid ...
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MTproto Proxy Security in Telegram App

In Telegram messenger, latest update, there is an option to set connection type to MTProto Proxy. Note: There is a detailed description by Telegram team on MTProto. Now telegram officially ...
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How do GnuPG smartcard generate reliable random data?

I'm generating a private key on my new GPG smartcard at this very moment. On linux, the random would be fed by the keystrokes on my keyboard, the network packets, the mouse movements etc. How does ...
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Cryptography behind chip based credit cards (smart cards)?

Why are chips safer than magnetic stripes? The answers to the above question explain that the chip based cards can not be cloned as the "secret number" is embedded in the chip and protected by the ...
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New TLS encryption-busting attack also impacts the newer TLS 1.3, is ECDHE_RSA also affected?

February 9, 2019: Source: New TLS encryption-busting attack also impacts the newer TLS 1.3 "Seven researchers from all over the world found --yet again-- another way to break RSA PKCS#1 v1.5, the ...
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How to encrypt data in frontend/backend with a key that is not stored anywhere and is only known to owner?

I have read bunch of answers and tutorials on how client side cryptography is not a good idea because of many reasons listed mainly in Javascript Cryptography Considered Harmful article. Some facts ...
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Can password strength be enforced with PAKE protocols?

Can a password strength policy i.e.: must contain at-least 8 chars must contain one uppercase letter must contain one lowercase letter must contain one number Be enforced if a PAKE protocol is used, ...
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Do you need more than 128-bit entropy?

UUID uses 128-bit numbers. Currently it is not feasible to randomly produce two UUIDs that are the same. Does that mean 128 bits of entropy is suitable for all cryptographic operations? I would ...
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Why do you need message authentication in addition to encryption?

I've been reading up on Authenticated Encryption with Associated Data. The linked RFC states: Authenticated encryption is a form of encryption that, in addition to providing confidentiality ...
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What ciphers should I use in my web server after I configure my SSL certificate?

There are many great questions that ask what is the best certificate to use for a website; but once the certificate is purchased, there is also the possibility to choose or edit the Cipher list. ...
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What are a keypair and a public key ring?

The GNU Privacy Handbook says: The command-line option -gen-key is used to create a new primary keypair. gpg --gen-key Does a keypair mean a pair of private key and public key? The book also ...
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How many iterations of Rabin-Miller should be used to generate cryptographic safe primes?

I am generating a 2048-bit safe prime for a Diffie-Hellman-type key, p such that p and (p-1)/2 are both prime. How few iterations of Rabin-Miller can I use on both p and (p-1)/2 and still be ...