Questions tagged [password-based-encryption]

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

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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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3answers
942 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: ...
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0answers
114 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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1answer
162 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
32 views

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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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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23 views

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 ...
2
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2answers
131 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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0answers
19 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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0answers
35 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 ...
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2answers
295 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: ...
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2answers
101 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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1answer
135 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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1answer
2k 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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1answer
102 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 ...
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2answers
181 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 ...
5
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2answers
320 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 ...
2
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1answer
105 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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2answers
1k 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 ($...
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0answers
75 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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2answers
118 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 ...
105
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5answers
85k views

Can you help me understand what a cryptographic “salt” is?

I'm a beginner to cryptography and looking to understand in very simple terms what a cryptographic "salt" is, when I might need to use it, and why I should or should not use it. Can anyone offer me a ...
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2answers
59 views

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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1answer
83 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
76 views

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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3answers
6k views

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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1answer
53 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
1k views

How do I verify a reset token if the token is hashed in DB?

I've been searching around the web for best practice how-to on secure password reset system (email with reset url), and the idea to hash the token in the database, which I did not implement at first, ...
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0answers
59 views

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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158 views

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
78 views

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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3answers
40k views

Length of encryption password aes-256-cbc

I'm encrypting a file with sensitive information with cat secret | openssl aes-256-cbc -a -salt > secret.enc I am choosing a random encryption password with <...
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1answer
601 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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2answers
214 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 ...
2
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1answer
776 views

Encryption in popular compression file formats - 7zip, RAR, Zip

When encrypting a file say with Winrar you have to enter a password. I am under the impression that this password is not stored anywhere but instead the password together with some other attributes ...
2
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1answer
515 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 ...
0
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1answer
536 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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1answer
110 views

New Passwording? [closed]

I just want to note before you continue reading--this does not specifically apply to hashes or the key to encrypted messages. However, I am initially thinking about password/key solving/remembering by ...
4
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3answers
2k views

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
128 views

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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2answers
32 views

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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4answers
21k views

Is password-based AES encryption secure at all?

For a few years I have put all my passwords in a text file and encrypted that file with a password using a software solution (Axcrypt) which uses AES-128. The password is not really strong, but I ...
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0answers
216 views

An efficient SPEKE protocol with curve25519

SPEKE is a very simple and elegant PAKE protocol. I think, one of the reasons why PACE has been invented and is now the ICAO protocol, is because SPEKE was patented. Fortunately, the SPEKE patent ...
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1answer
138 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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2answers
423 views

How to design a cryptographically secure file hosting service

How would one go about designing something like Google Drive/Dropbox providing the following features: files are encrypted and decrypted on the client files can be synced between devices the service ...
2
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1answer
258 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
230 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
360 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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1answer
714 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 ...
1
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1answer
974 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 ...