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Questions tagged [password-based-encryption]

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

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62 views

Which algorithm is safest if we exclude AES, Twofish, Serpent and Whirpool? [closed]

TLDR: Which algorithm is safest if we exclude AES, Twofish, Serpent and Whirpool? Full version: Hello, my threat model is archiving and backing up important and private files. Files will be stored ...
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0answers
26 views

brute force slowing down causes

Does winrar encryption slows down brute force?how fast could a rar file be brute forced by home pc? by GPU based machine?how fast it could be brute forced by supercomputer of 200 petaflop?assuming ...
3
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1answer
115 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 ...
0
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2answers
83 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: ...
3
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1answer
94 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 ...
0
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2answers
94 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
563 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 ($...
4
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0answers
65 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 ...
2
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1answer
92 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 ...
1
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2answers
55 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 ...
1
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2answers
113 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 ...
1
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1answer
144 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
66 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 ...
2
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1answer
70 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 ...
0
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1answer
40 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. ...
1
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2answers
84 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, ...
1
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2answers
93 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 ...
2
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1answer
1k 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: ...
3
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0answers
57 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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2answers
148 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 ...
2
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1answer
76 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-...
1
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2answers
150 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 ...
1
vote
1answer
445 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 ...
2
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1answer
450 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
470 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 ...
4
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3answers
5k 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 ...
5
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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 ...
0
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2answers
31 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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2answers
119 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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0answers
188 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 ...
1
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1answer
123 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 ...
3
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1answer
237 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 ...
0
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1answer
208 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 ...
0
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1answer
326 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 ...
6
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2answers
296 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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votes
1answer
644 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
vote
1answer
819 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 ...
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1answer
543 views

How important is length and complexity of personal password for AES-256 encryption?

I want ask you how important is to have complicated personal password for AES-256 crypto? For example if I use these two "types" of passwords: pass123 ...
0
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2answers
164 views

Will knowing clear text value behind encrypted data help hacker find password?

I am building an Android App where I will be storing some encrypted data in a database. To ensure that the user has entered the right password, I have encrypted my own secret phrase and stored it in ...
1
vote
1answer
1k views

How much time will it take to brute force a password

I am building a client-side app that will encrypt data, using password-based key generation, into the database. Can someone verify my calculations to figure out what is the right number of iterations ...
1
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2answers
848 views

UNIX password scheme and encryption function

Recent versions of Unix store encrypted passwords in a file that is not publicly accessible. Such files are called shadow password files. In the UNIX password scheme, if only the operating system and ...
4
votes
3answers
998 views

Does encrypting data multiple times using different passwords increase security?

Does encrypting plain-text data multiple times using different passwords provide a greater level of security? If so, what encryption algorithm would be best for such a use? Would it be beneficial to ...
1
vote
1answer
437 views

Question about hashing passwords with PBKDF2

I am new here and new to encrypting and securing passwords, so please forgive me if this question is not posted to the right location or if my question is bad. I have been working on a web app in ...
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1answer
108 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
votes
1answer
339 views

Can key hardening compensate lack of entropy?

In the context of an offline brute-force attack on encrypted data at rest (say, a password-protected AES encrypted file), is a password with 64 bits of entropy and 65536 rounds of key hardening just ...
17
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2answers
621 views

Is there any SRP-like key exchange only using “standard” cryptographic primitives?

I am looking into PAKEs (password-authenticated key exchanges), and it seems like SRP (Secure Remote Password) is essentially the de-facto standard. However, implementing SRP actually requires doing ...
0
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1answer
73 views

Are there any downsides to key stretching an already high quality entropic key?

For example, if we grab 50 bytes from a high quality source and run them through a key stretching function like Argon2 and have it generate a 32 byte secret for AES. Is there any downside to this? Do ...
3
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0answers
108 views

SPAKE2 - Pairwise keys with multiple participants

With magic wormhole, I've discovered SPAKE(2) and I was wondering if it is possible to derive pairwise shared keys between multiple participants still using one password only. More precisely, amongst ...
1
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1answer
647 views

storing salt in app

I want to create a key for my realm database wich work with AES-256 and for encryption wants a byte[64] key. I read this good question about create a key from 4 ...
1
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1answer
201 views

securing the keystore

When generating a public-private key pair you have the option to secure the keystore with a password. where is that password stored, is it a hashed version that is stored and if that is so which ...