Questions tagged [password-based-encryption]

Encryption using a key derived from a password or passphrase entered by the user.

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Using encryption as authentication

I am building an app in which I would like to encrypt user data and support offline login. From this answer about using passwords for encryption: Best practice is to use a PBKDF to generate a 'key ...
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5answers
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How passwords are fed to key derivation functions?

Suppose I want to encrypt data, send it over the network, and decrypt it on the receiver side. I know the elegant way to do this is by using a symmetric key to encrypt the data and an asymmetric key ...
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1answer
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Argon2 or scrypt instead of PBKDF2 with AES

Is using scrypt or argon2 a better key stretching technique with AES compared to PBKDF2 or bcrypt with regards to a quantum computer brute force attack. The brute force attack I'm referring to is ...
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68 views

Simple proof of ownership of a password

I want to do a completely serverless p2p chat application on web browsers, so it won't even have a database to store accounts, but I still want to have some kind of identity system on it (an user can ...
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1answer
107 views

Why use PBKDF2 over SHA-512 to derive AES encryption key? [duplicate]

Suppose I am using user passwords to derive AES-128-CBC encryption key. This key will be used to encrypt some sensitive data for the user so that even the website owner / operator can not decrypt it. ...
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How would quantum computers affect password based encryption?

At first glance: Assuming that the output of the password hashing function is large enough, quantum computers should have no effect on password encryption as on symmetric cryptography in general. Is ...
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1answer
269 views

End to end encrypted web chat app with stored messages in database

I am working on a web app with an integrated chat. All chats can only occur between two users - not more, not less. I am very concerned with security, so I would like to encrypt all chat messages with ...
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0answers
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Encrypted ZIP and plain text attack [duplicate]

I have a Zip archive containing a single password-protected file file.txt. The encryption is "ZIP 2.0 Default Encryption" (ZipCrypto). I know what kind of text (...
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2answers
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Why cryptsetup default KDF is PBKDF2 and not Argon2(id)?

I plan to do a clean install of ArchLinux with Full Disk Encryption (with LUKS) but I'm not sure to understand the default KDF choice (PBKDF2+SHA-256). I didn't manage to find any pieces of evidence ...
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Should we run PBKDF2 for every plaintext to be protected or should we run PBKDF2 only once?

I am going to store secrets from users. The secrets need to be stored confidentially. For this question, I am concerned only with confidentiality (not integrity). Here is how my encryption scheme is: ...
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How safe can PKZIP-compatible encryption be?

PKZIP encryption has been around since 1990, and its decryption is directly supported in most desktop environments (Windows, MacOS, most Linux distros). This makes it one of very few options when ...
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Is PKCS#5 deterministic if both sides use an agreed salt and iteration count

In a system were both sides have access to a common secret, and publicly exchange an iteration count and salt, can a PKCS#5 (Password-based Encryption Standard) algorithm be used to generate a key ...
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What are some best practices to handle user password in shell script and environment variables?

I'm new to this community. Currently im working on a project which involves handling user password in shell script. Following steps describe my password consumption flow: Get password from user ...
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1answer
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When to use Argon2i vs Argon2d vs Argon2id?

I've read the manual, and multiple articles / StackExchange posts about this topic, but still can't decide which implementation of Argon2 is best for my use case. I want to securely encrypt passwords ...
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0answers
27 views

Using PIN to enable MFA for YubiKey-based logon provider

I've created a custom credential provider (for Windows) that allows logon just by inserting a YubiKey. The user's Windows password is protected as follows: ...
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Authenticating without sending password to the server, and store data encrypted with password derived key on server

I am trying to think of a scheme that would allow a user to authenticate to a server, whithout sending the password to the server, and to also derive a symetric key on the client (that also never gets ...
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1answer
198 views

Using a non-secure random generator for IV or salt generation

I was just looking at a post on Code Review when I noticed the other answer to the post. While I would agree mostly with the answer, I do however doubt if having a Cryptographically Secure PRNG is ...
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How to validate a PBKDF2 password

I want to encrypt several files correctly with a PBKDF2 generated key (using a password and salt), I am currently doing so but if I enter the wrong password, as expected an exception occurs. Note: ...
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1answer
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What is this called: encrypt $X$ with key $E$, decrypt $X$ with key $D$?

I am a software developer interested in developing an application with cryptography. I can explain what I want to accomplish, but I do not know the technical terms for the cryptographic functions I am ...
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2answers
362 views

Best practices for saving encrypted user data without a database

We are setting up a web application which requires users to submit sensitive data. Since entering all the required data may take a long amount of time, we want to give them the option to save their ...
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2answers
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Argon2 for both password storage and key derivation

Is using Argon2 for both password storage and key derivation secure? I'm planning on using different salt values, of course. The basic concept is something like this: Alice has some secret data ($...
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0answers
90 views

Upgrading key derivation by adding a XOR with a known value

In general keys for password based key derivation are derived from a password hash such as the old PBKDF2 function or Argon2, possibly followed by another derivation function to derive data and ...
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1answer
122 views

Is it safe to publicly expose PBE-protected PGP secret keys?

I am working on a PGP scheme where a private key is created offline (and in volatile memory) and must be reused on very rare occasions to sign a piece of exportable data. The private key is locked ...
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Is it possible to determine the number of characters used for a password used to encrypt a file with AES 128?

I lost a password for an ethereum wallet at the end of 2016. Computer immediately shutdown and password was not recoverable. I know there are many potential avenues for narrowing my search for what ...
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2answers
137 views

How secure is a system that retrieves encrypted private keys from a public database?

The system in question is one with multiple users. Each user has a password associated with their account, and each user owns several public-private keypairs. A user's private keys are encrypted using ...
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1answer
185 views

Hardware, Handheld Password Manager

I am currently working on a hardware project that will utilize the native USB and keyboard emulation capabilities of the Teensy device. Essentially, the user will store an encrypted password database ...
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1answer
128 views

Does having an SHA256 hash compromise PBKDF2 secrecy?

If I have a password pwd, and I hash it with SHA256 and send it to a server for authentication (server will apply ...
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1answer
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Password protection in ARJ: 3 characters of password are retrievable

On this site there is information that one can know first 3 characters (bytes) of the password without brute force. I know that ARJ in older versions has very simple encryption, i.e. XOR with ...
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82 views

Perform calculation on encrypted numbers

What i am trying to achieve ? I am developing a carpooling solution powered by Blockchain and IOT. This one is supposed to be technically convenient and without compromising on the privacy part. ...
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2answers
130 views

In SRP, is the client protected from server impersonation?

Assume use of SRP over an otherwise insecure unauthenticated channel where the user running the client side has chosen a password, the user only uses that password with a trusted SRP client software, ...
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2answers
166 views

Mechanism of PBKDF in encryption key generation with passphrase

I want to roughly understand how the mechanism works of generating an encryption key from a passphrase, by which we encrypt a volume or file. I'm familiar with public key encryption, the concept of a ...
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1answer
3k views

AES-256 password cracking time

My question is kinda simple. I want to use AES-256 encryption to encrypt my backup. Using a password like this: ...
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0answers
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Did “The Catena Password-Scrambling Framework” make an error in the reduction of its pseudorandomness?

I was reviewing the most recent version of the Catena paper and they made some claims that I find questionable in their reduction of the pseudorandomness of the output of Catena (p. 32). First I will ...
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Zencash uses your passphrase to identify AND unlock a wallet - how is this secure?

When looking into Zencash I stumbled into myzenwallet.io (by the Zencash creators), which gives you the option to enter a passphrase to generate a wallet (seems normal), but then after creating your ...
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1answer
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How much time would it take to crack time mnemonic phrases in these scenarios?

How long time would it realistically take to crack each of following scenarios and how many combinations does each scenario consist of? Mnemonic Phrase, it is not known if we are looking for a pass-...
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2answers
374 views

Does AES-GCM without security tag turn into regular CTR Mode?

We are looking to implement a simple password based key agreement scheme. Part of this is deriving a symmetric key from a common passphrase known to both parties involved. This symmetric key is then ...
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1answer
759 views

Would it be safe to store GCM nonce in the encrypted output?

I'm looking to use AES-256 GCM to encrypt and authenticate a file containing sensitive information. I am a bit loss on where to store the nonce that is required for GCM. Would it be adequate/safe to ...
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1answer
612 views

Key recovery after AES-ECB encryption of two blocks with some known plaintext/ciphertext

I am analysing a small, bespoke end-to-end encryption service's source code, in particular their user registration process. I am finding some interesting things going on and I am wondering if there's ...
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1answer
630 views

Which cipher to use with openssl for shortest output?

I'd like to encrypt my 12-24 words seed for my bitcoin wallet with openssl command line tool to be able to have it with me on paper without the risk that somebody could use it Which cipher should I ...
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What's the difference between PBKDF2 and HMAC-SHA256 in security?

Being a software developer, I haven't dealt with crypto so far. So I know very little, sorry for that already. I am aware that you should use bcrypt, scrypt, Argon2 or PBKDF2 for generating a hash ...
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3answers
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Password-based cipher with fast encryption

Define a password-based cipher as a cipher which decryption key is a humanly memorable password, thus optimistically at most 28 to 44 bits of entropy (per the obligatory XKCD). For a password-based ...
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2answers
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Prevent communication with a node assuming full transparency

I have an IoT device that I have set up to communicate with AES-256-GCM encryption. The working version has the encryption key stored in plaintext in a file on the device (this is going to be improved)...
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2answers
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What is the difference between algorithm and passphrase?

If there is an algorithm securing a document, then why is there also a passphrase when the algorithm is already there? And if there is a passphrase securing a document, then why do we also use the ...
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1answer
161 views

An efficient PACE protocol with curve25519

The PACE protocol is a password authenticated key agreement which is widely used. For instance, in the electronic ICAO passports as the so called SAC protocol. PACE is standardised in ICAO DOC9303 ...
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1answer
360 views

I am trying to create a simple image encryptor in python result isnt promising [closed]

I am writing a program in python (myself) to encrypt images. I don't want or expect it to be state of the art encryption and safe at the end but i have a problem. The result encrypted image still has ...
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1answer
258 views

Secret Key Exchange and FIPS or Industry Standard Compliance

I am trying to collect several information regarding Security Industry Standards and the FIPS compliance to meet the security standards for our future development system. In this case, we have two ...
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1answer
388 views

Can a Password be Derived from a AES key?

This thought randomly popped into my head and I have not been able to find a clear, defined answer for it. Given an AES key, lets say an AES-256 key which is derived from a user password, is there any ...
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397 views

Password derived hash to encrypt known plaintext as password check

The title sounds way too adventurous for what it actually is. I am currently building a system which features some encryption. There is already a system in place, which is built after that scheme if ...
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1answer
989 views

Best complementary algorithm to AES

I'm looking to protect sensitive data from deletion by hosting it on Amazon Glacier. I'd like to secure that data against possible hacks of Amazon by encrypting it, and I'd like for the data to be ...
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1answer
1k views

What is the best way to derive a encryption key from the serial number?

I have a couple of Android devices which run my app. Every device has it's own unique serial number - a hex string 16 characters long. The app needs files, which usually reside on external SD. These ...