Questions tagged [encryption]

Encryption is the process of transforming plaintext using a cipher into ciphertext to make it unreadable to anyone except those possessing the key. Decryption is the process of transforming that ciphertext back into plaintext, using the key.

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1answer
45 views

Create a ciphertext that decrypt to different plaintexts with different keys in RSA

(This is inspired by this question 1; have also read this question 2 but it's one-time pad) I would like to know, given two message $m_1$ and $m_2$, as well as public keys $(e,n_1)$ and $(e,n_2)$, ...
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How challenge response password recovery mechanism works with disk encryption? [migrated]

For the sole purpose of learning, I am trying to figure out how disk encryption software is able to recover password of an encrypted disk using a challenge response mechanism. Th recovery process ...
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20 views

complexity of ElGamal ECC and Menezes-Vanstone ECC?

How to compute the complexity of ElGamal ECC and Menezes-Vanstone ECC?
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State of the Twofish encryption cipher - is it broken?

Twofish was one of the finalists in the last cipher competition together with Serpent and AES, where AES won. Do you know of any cryptanalysis on Twofish and if its considered "broken" or still ...
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How hard is it to guess a 8 digit PIN?

Say that there are different live situations where you have to select own PIN numbers. Can someone say if it is possible to guess a 8 digit pin within 3 tries, given any methods or resources? Is ...
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0answers
47 views

What is the formula to calculate password entropy? [closed]

I saw in another thread: Is using 7-8 random words from all words of a language as password a good idea? These calculations: If we assume that English has 171,476 words. Then with 8 words the ...
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1answer
114 views

How safe is my method

I'm building a website. I have an API which takes 2 parameters: delete_user(user_id, hash). And there is method to evaluate hash using SHA512: ...
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0answers
19 views

What is the best way to encrypt whole partitions with Ed448-Goldilocks?

I like crypto, but I'm a bioanalytical chemistry person by trade. I like this algorithm and was wondering if I could use it to encrypt partitions like a MBR that prompts a passphrase, like BitLocker.
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25 views

Is there a program i can use to find a hidden message in a BMP file?

I am working on a puzzle and think there is a message hidden in one of the files that is a BMP file. I am wondering if there is a program somewhere that could find it?
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24 views

Would these Vigenere cipher use cases be considered secure? [closed]

I've a couple of questions about my knowledge of the modern and secure use cases of vigenere. I'd like to know whether or not they'd be considered secure by todays standards - By that I mean easily ...
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2answers
61 views

Is there something like a secure hashmap?

TL;DR: Is there such a thing as a hashmap whose contents cannot be read unless you have the right encryption key, and where each encryption key only works for a specific key value pair? More context: ...
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How can I decrypt the encrypted text of GitHub opensource project? [closed]

In Github I found this gfwlist text, but this is not plaintext, it's encrypted text, we know GitHub is a opensource code manage platform, why it is encrypted? and there do not give a decryption ...
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default value for rsa_padding_mode in openssl cms command [closed]

I am trying to generate the signature for a file using openssl cms command. Wanted to understand what is the default value for rsa_padding_mode. I did not specify anything for this parameter and I ...
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2answers
60 views

PRNG next bit test

I would like to know whether a specific PRNG satisfy the next-bit test or not. will satisfying all of NIST statistical tests on PRNG guarantees passing the next-bit test? Or is there a specific ...
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1answer
49 views

Proving the right encrypted message was sent

Total amateur to crypto here but I've searched and searched and am at the extent of my knowledge. I've gone down several avenues to satisfy what I'm looking for but I'm just going to describe what I'd ...
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1answer
70 views

Double 3DES/TDES Encryption

If 3DES/TDES (officially TDEA or Triple DEA - Triple Data Encryption Algorithm) encryption is used twice, using 6 different keys K1-...
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1answer
52 views

RSA: How to compute plaintexts knowing ciphertexts, public key and relation between plaintexts

I'm trying to solve an exercise where you have to compute two plaintexts $p_1$ and $p_2$, knowing the corresponding ciphertexts $c_1$ and $c_2$ and the public key, of which $e=3$, and $n$ is a large ...
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1answer
89 views

Cipher comparison chart/table?

I'm more of a visual person, so a chart or table layout usually works best to help me "see". I'm just trying to locate a resource that shows me where the various ciphers fall in relation to each ...
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Niederreiter cryptosystem sources

I want to study about Niederreiter cryptosystem and I want your opinion about sources, papers, etc. I found stuff on the Internet but I want to know if there is a good source that you may know. I want ...
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2answers
680 views

Is direct RSA encryption of AES keys secure?

I am wondering: If we take this scheme/procedure and each of it seems very secure (to me at least), is it truly secure or is there a vulnerability hidden in the process? This is the scheme: Bob has ...
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1answer
45 views

Recognizing and decrypting custom cipher with known plaintext and ciphertext

I've been trying to reconstruct an encryption algorithm that produces a known ciphertext from a know plaintext. I have done some analysis: the algorithm operates on single bytes a plain text can be ...
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1answer
16 views

decrypting el gamal encrypted messages in regards to k being used

i am trying to understand the differences of using k in the following scenarios to better understand the protocol and most importantly the consequences of using such k. so i wonder, some user, call ...
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0answers
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attacks and defenses on multi party Diffie-Hellman protocol

I tried to create a 4 partied Diffie-Hellman implementation for 4 people using its cyclic group property. However, I am not sure regarding those 2 issues, and would appreciate if you could elaborate ...
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2answers
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Is there any vulnerability in this scheme?

We want to design a symmetric encryption scheme. Note that the following things are true for our system: The plaintext P will change every time for a given user. A user will choose a password which ...
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2answers
121 views

What encryption to choose from the SSL library in python 3?

I've been researching some of the types of encryption that the python SSL library uses. Among them the best I've seen are: ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx = ECDH Au = RSA Enc = AESGCM (256) ...
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1answer
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Why is the second XOR operation in OCB mode necessary?

In Rogaway's OCB mode, the offset (derived from the key) ist XOR-added twice: Once to the plaintext block, and a second time after the Encryption. I am wondering, why the second XOR operation is ...
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How to securely store / generate a private key for client side encryption when using SQRL as login? [closed]

I am a developer who until now has done very little with encryption. Steve Gibson's explanation of SQRL (Secure, Quick, Reliable Login) has solved a lot of problems for me regarding encryption, most ...
3
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2answers
77 views

Multiple (RSA) public key encryption how to verify others received the same information? Non-deterministic encryption

I have an RSA system between multiple parties. Alice takes the targets (Bob and Oliver) public keys and encrypts a message using them and sends it to them. All parties know each other's public keys ...
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1answer
80 views

Is more ECDHE or RSA currently recommended?

Lately I have seen that many websites warn us of changing RSA for ECDH, and that the latter is much better if we use its "ephemeral" form or better known as ECDHE. So is ECDHE recommended to use more ...
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3answers
251 views

How secure is XOR-CBC?

How secure would this be? To be clear, I mean replacing the block cipher encryption step in the Wikipedia diagram explaining CBC with plain old XOR? EDIT: Replace ...
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1answer
74 views

EL Gamal Attack without a secret key

I have the following data where all the inputs are Big Integers, group size $p$, group generator $g$ public key of the receiver $y$ $c_1$ and $c_2$ Random Number as well I am trying to execute an ...
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1answer
61 views

How to store encrypted solutions of a find location game?

I'm coding a bot on Telegram to sustain a quiz game. A group of people (authors) can upload photos of streets or particular landscapes that they have found on internet, without any description, and ...
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1answer
62 views

Crypto AES for authentication

Is it secure to use authentication strategy like this: store key in database - crypto.randomBytes(32) store IV and encrypted data in user cookies - ...
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28 views

Server stored, encypted messaging app

For my personal research, I have to create a messaging app, but security is only important part of application, security from MITM (man in the middle attack), at device end, and at server level. (note:...
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2answers
145 views

The importance of randomness in the creation of a key

Why does it matter what kind of random number generation is used during key generation? E.g. this answer states ...
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1answer
48 views

Stream cipher - Many time pad

I understand the concept that when you xor the cipher texts you get the XOR messages cause the keys get XOR-ed and cancel out... This is at least the case when both the messages are of equal lengths. ...
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2answers
2k views

Is using 7-8 random words from all words of a language as password a good idea?

The Bitcoin Bip-39 dictionary has 2048 words. And a random 24 of them are pretty secure together. What if the source is bigger (all words in the language) but there are only about 7-8 words? These ...
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0answers
38 views

If we have chunk encryption for AES-Rijndael-CBC, should we hash Authenticate/tag each single chunk with a hash vs whole file?

was frustrated by which one to pick and my brain could not guess which one is better Authenticate the whole file as one with a hash vs authenticating each ciphered text. So very quickly: i have super ...
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0answers
37 views

Are TCP socket connections over private wifi encrypted using WPA2 PSK? [migrated]

I recently made a very basic TCP client/server system in C++. I got the client and server running between two computers connected to my private Wi-Fi. Since a private Wi-Fi is encrypted, does that ...
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1answer
52 views

How much long the key should be to create a secure encryption with One Time Pad? [closed]

For example would a key with 15 random letters be enough to protect a 52 letters plain text?
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1answer
122 views

What are easy yet fool proof ways of ensuring that AES encryption algorithm works like it should and no bugs/developer mistakes have sneaked in?

As a developer when it comes to encryption, there is an insane amount of weakness/mistakes/bugs that the programmer can add to the encryption algorithm. So a pretty general question to the crypto pro’...
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2answers
61 views

AES CBC in need of multiple IV's, possible to avoid creating duplicate iv's by using resulting cipher text 16 bytes as next iv?

I saw a little close to these questions but not exactly. Encryption method AES-256-Rijndael-CBC: if we have multiple cipher chunks that look like this: {iv}{cipheredchunk}{chiphered chunk}{chiphered ...
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1answer
113 views

My RSA decryption doesnt match answer

Break the RSA code whose key is $(n, e) = (8369428283, 1234567)$. Find the deciphering key and then decipher the message under the assumption that the plaintext consists of 7-letter blocks in the ...
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1answer
80 views

Does adding OWF of the private key to encryption scheme hurts security?

Suppose I have a symmetric semantic-secure encryption system $\Pi = (Enc, Dec)$ and an OWF $f$. Now, define the following encryption scheme $\Pi^{'} = (Enc^{'}, Dec^{'})$ where , $Dec^{'} = Dec$ and $...
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1answer
547 views

Multiple AES Key Derivation from a master key

I need cryptography advice regarding this issue. Kamus is a service that encrypts secrets for applications running on Kubernetes. When using AES (actually, Rijndael) symmetric encryption, Kamus uses ...
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1answer
51 views

Are there low-bit hashing or encryption functions for teaching cryptographical concepts?

I understand how hashing and encryption/decryption work at a very high level, where the functions work as a black box. Hashing scrambles the input in a non-uniquely reversible way, whereas encryption ...
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0answers
80 views

How to upgrade encryption version of many large files?

Assume that I operate a user-facing online file syncing service that offers end-to-end encryption of large files, such that files are encrypted client-side first, then uploaded to the server for ...
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10answers
6k views

What's the truth about this “absolutely unbreakable” cipher?

A story appeared on Forbes today claiming that we now have an absolutely unbreakable cipher. It cites a paper published in Nature Communications. However, I'm skeptical: But what if there were a ...
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1answer
56 views

Get base 64 key having the decrypted and encrypted text

I am doing a pentesting-challenge where I have the text both encrypted and decrypted. By looking at the decrypted text I know that it is base64, and to pass the ...