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

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### How strong would be create a password through AES ECB encryption?

Suppose that I want to use a "poor man" password management working as follows: 1. I choose and remember one single master password (for example "78HK+jm?329"); 2a. for any bank, ...
53 views

### Is it safe to use the same password for both VeraCrypt volume and Windows Login?

I encrypted my entire volume with Veracrypt which prompts on start up and asks for a password, great. Now after every startup is finished or everytime I leave the computer unattended (after a quick ...
36 views

### Hashed password used for encryption and for user authentication at the same time

As I am fairly new to cryptography, I would like to understand how to, in a simple way, implement a system that would achieve the following: the user would have to setup a password, which would then ...
58 views

### Is it possible to send a file that cannot be opened or copied by the reciever, but only by a pre made program?

I couldn't think of a better question to ask, but I will explain more here. I want to be able to send a Word document to a server that will work with the document data. Are there any good ways to do ...
43 views

### Are there any best practices/recommendations for/against using client-side password hashing?

I do not mean generating a hash on the client side and then storing it in the database directly. I found a few questions with similar theme, but most of those answers assumed a scenario where ...
49 views

### Why does CMS' PasswordRecipient use a KEK?

When using openssl cms -encrypt -pwri_password, it follows the process described in RFC 3211, which passes the user-provided password into a KDF, but then, rather ...
100 views

### AES and the Feistel Structure Used Together?

In Dual Watermarking in Tele-radiology using DWT for Data Authentication and Security, the authors wrote: The encryption process uses the Feistel structure consisting multiple rounds for processing ...
3k views

### Password hash contained '\x00' in middle, resulting in ValueError from bcrypt.hashpw

I have some code that accepts a password in string format, and hash it with SHA3-512 before passing it to bcrypt for hashing. However, by some coincidence, I found a test case that produces a hash ...
86 views

### Am I using these key derivation functions correctly?

I am a bit confused about key derivation functions. I am trying to use the argon2 KDF from the passlib python module to do the ...
68 views

### How to encrypt a text file in a portable manner based solely on a password?

I used to use openssl aes-256-cbc, but the problem I have with this is when I try to decrypt in a different version of the distro it fails, as if it depends also on some internal key or something, ...
93 views

### Making a secure file sharing scheme usable

I am trying to realize a secure file sharing scheme based on asymmetric crypto. Users will access this via browser. In short, it works like this: Users register and set their username and password. ...
210 views

### Best practise for encryption in a password manager

I'm trying to make a password manager for Windows installed computers, and after researching the best ways to encrypt the passwords in the database (I'm new to cryptography) I think I've come up with ...
2k views

### How are recovery keys possible if something is encrypted using a password?

I thought that encryption works as follows - it is about changing the thing we want to secure using an algorithm and using the password to mathematically change the secured content so it is unreadable....
132 views

### Encrypting data with HMAC-SHA1 challenge response as the key

I came across a piece of software that uses the following algorithm to generate a symmetric encryption key to encrypt data. Generate a non-secret 64 byte random string $M$ (fixed challenge) Generate ...
50 views

### End-to-end photo storage

I've been tasked with developing an app that will need to store photos a user takes securely, and I've been struggling to think up a method to do this. What I was thinking so far is as follows: When ...
696 views

### How to choose parameters for Argon2 for a password vault

I'm creating a password vault, and I plan to use Argon2id to derive the master key from the master password. For encryption, I plan to use XChaCha20 with Poly1305. To be clear: a set of multiple ...
116 views

### What are some of the alternatives to password based file encryption?

With the ever increasing risk of attackers compromising password based encryption by brute forcing or guessing passwords, are there alternatives to this traditional scheme of deriving encryption keys ...
48 views

### Issue with decrypting self-coded AES

Summary: As a trainee, I got the task to extract encrypted passwords of our external password manager (Zoho Vault) and decrypt them. The documentation regarding how to decrpyt them is...none. I ask ...
278 views

### For TCG-Opal drives, which password is used to derive KEK?

SEDs use a user password (PIN) to generate KEK by a KDF algorithm. The KEK is then used to encrypt the MEK (where MEK is internally generated in the drive). But TCG-Opal drives have 9 locking-ranges ...
75 views

### How to provide secure password based encryption with password reset option

I am trying to build website that will encrypt some data for the user using his/her the output of scrypt on it, now the idea is that this schema is not flexible because if the user loose their ...
73 views

### Do all forms of symmetric encryption require multiple pieces of information? (nonce, iv, etc)

I'm attempting to learn encryption and have a very basic grasp of it, but I have questions. First, I'm looking to use AES. I want to take text, encrypt it with AES using a variable-length key, and ...
163 views

### Security limits of password-based encryption

A reasonable way to do password-based encryption is: put the passphrase¹ and nonce in a well-parametrized memory-hard iterated hash function like Argon2, to derive a key 128-bit or larger. output the ...
4k views

### Relation between Zoom id,password and join URL [closed]

We all are using zoom application for joining/hosting meetings in this corona virus period. As we create a meeting, a new id, password and a url is generated. Some real examples follow- Id: ...
138 views

### Do all PAKE assume that all parties already have a password?

I was looking for a means to perform a key exchange without relying on a PKI. I discovered Password Authenticated Key Exchange (PAKE) and after reading J-PAKE; I have the following questions: Do PAKE ...
68 views

### Can a duplicate ssh private key be dangerous?

For convenience I had an id_rsa keypair and duplicated them with a new name. I may or may not use them consistently on different machines. (The reason was to keep an existing id_rsa on a machine I ...
179 views

I would like to understand the mechanism behind wpa/wpa2 algorithm. Is there any script that can put this theory:(Key = PBKDF2(HMAC−SHA1, passphrase, ssid, 4096, 256)) into action to test it ? I made ...
153 views

### In veracrypt when i generate a random keyfile, does the size of the keyfile mean anything?

thanks for looking at my question, i have been getting several different answers to this question so i thought i might ask it here, when i create a random generated keyfile in veracrypt, does the size ...
113 views

### 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 ...
283 views

### 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 ...
803 views

### 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 ...
104 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 ...
894 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. ...
163 views

### 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 ...
2k 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 ...
138 views

### 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 (...
3k views

### 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 ...
1k views

### 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: ...
936 views

### 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 ...
5k views

### 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 ...
74 views

### 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 ...
346 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 ...
2k views

### 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: ...
126 views

### 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 ...
562 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 ...
3k views

### 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 (\$...
129 views

### Upgrading key derivation by adding an 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 ...
148 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 ...