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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Can't figure out the encryption [closed]

The ciphertext: Fubswrulqwb lv wkh sudfwlf dqg vwxlv ri whvwlf ryhu wklv xvhvwlq ri dwhvhvhfuhv ejwhfq. Pruh jovqshq, fubswrulqwb lv deyqxbuwlqj dqg exsduqbg rqrq ykiwhk vdssrkwxmtqj dqg wkhslnkrdq ...
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How to prove that signature hash is wrong without reveal message

Let's say we have Bob, Alice and third party. Bob make message signature hash and upload to third party, then encrypt message with Alice pub key and send it to Alice Alice receive message and decrypt ...
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Possible to encrypt message without knowing recipient public key?

Assume Bob is sender and Alice is future recipient. In ideal situation Bob know Alice public key, and encrypt message with it. But what if Bob don't know Alice public key (he only will know Alice ...
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which DH protocol is safer in communication with given condition?

I am trying to understand some concepts such as DH problem and its variants. I have the following question from the book I read. (note that I translated the question from my language to english) ...
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Input/Output size of compression functions

I know that DES has 56 independent key bits, and that 3DES has 168 independent key bits by using 3 seperate 56-bit DES keys. 3DES also has a block size of 64 bits. If I use 3DES as the underlying ...
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Safety of using non-encrypted hashes to identify encrypted data in a key-value store

I saw posts tangentially related to this, but not this one specifically. I'm building a content-addressable storage layer where I'd like to store the contents encrypted. The question is what is a safe ...
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Where on Stackexchange could i post work on new factoring methods [migrated]

What board can i post work showing original framework for factoring methods, so that i can get insight from others with more expertise on why such a framework functions? I have some understanding now,...
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Source of encryption scheme used in blockchain based IoT

I've found the following encryption scheme UserA: $$sk_A, pk_A = sk_A \cdot G$$ UserB: $$sk_B, pk_B = sk_B \cdot G$$ Enc: UserA $$u \in \mathbb{Z}_q^* \\ Y = u \cdot pk_B \\ S = H(U) \oplus m \\ C = (...
coolgirl Leon's user avatar
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ElGamal signature scheme problem and unsure whether my calculations are wrong or that's the answer

Trying to solve problem with verifying a message through the ElGamal signature scheme and I end up getting two different values. I'm given a prime number p=881 , e1=3, d=60 , and a random value r=11 . ...
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Assistance required with a suspected Nihilist Cipher text associated with a 1948 Cold Case [closed]

I have found a cipher text that shows up as a Nihilist Cipher when entered into the dCode cipher identifier. The text was found in a torn slip of paper bearing the words TAMAM SHUD, the last two words ...
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Does combining a stream cipher and block cipher produce any vulnerabilities?

In particular, AES-CBC with Blake2b for HMAC combined with xChacha20-Poly1305. The scheme is to encrypt with xChacha20-poly1305 first, using a key derived from a high entropy password using argon2id ...
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Is it possible to detect Stealthy False Data Injection attack through chaotic cryptography?

I am doing a research on detecting Stealthy False Data Injection (SFDI) attacks in a smart grid context (a related paper). Besides I am working on a chaotic cryptography (e.g. with Lorenz attraction) ...
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Decrypt RSA knowing N, invp, and invq

im having a problem while solving a RSA problem, so i have python script to create a RSA key and cipher, from that i have n, invp, and invq. so my question is possible to decrypt the message only with ...
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Does using multiple encryption algorithms with different keys on the same cipher text improve security?

I'm looking for maximum possible security. My current scheme is xChaCha20-Poly1305-xSalsa20-Poly1305-AES-CBC-HMACSHA-512. Does combining these algorithms increase security if implemented correctly? ...
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Is it secure to encrypt an authentication token using another possibly hashed authentication token?

I'm working on a web app ("main") which acts as a central access hub for several other web apps ("children"). The users are supposed to authenticate in the main app, resulting in a ...
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Is gcd(e,p−1)=1=gcd(e,q−1) similar to gcd(e,phi(n))=1?

I wonder, is $\gcd(e,p−1)=1=\gcd(e,q−1)$ similar to $\gcd(e,\phi(n))=1$ ??
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Does the use of a passkey (FIDO) link your physical device id, eg IMEI, to that specific passkey?

Passkeys are being introduced. From what I understand so far, a passkey involves the storage of a private key, and retention of a public key with the internet service. Eg Google, Apple, Microsoft, ...
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In RSA Encryption, Can I choose the public exponent e > m (modulus) ? or e > φ(n)? [duplicate]

In RSA ,the encryption, Can we choose the public exponent (e) greater than m (modulus) or e > φ(n) ? I wonder about choosing public key exponents (e) because the most information on the internet or ...
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Hybrid key exchange in TLS 1.3

In Hybrid key exchange in TLS 1.3, they mention that with a hybrid approach, we concatenate the shared secret from each method (say KEM like Kyber768 + classical ECDH X25519 = X22519Kyer768). ...
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Is using a CPA secure public key encryption twice on two halves of the message with different keys secure?

If $\Pi=(\mathrm{Gen},\mathrm{Enc},\mathrm{Dec})$ is a CPA secure public key encryption protocol, is the following public key encryption CPA secure? $\Pi'$: $\mathrm{Gen'}$: Run $\mathrm{Gen}$ twice ...
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In RSA Encryption, Can the public exponent e > m (modulus) ? and can we choose any public key without paying attention to the conditions? [duplicate]

In RSA ,the encryption, Can we choose the public exponent (e) greater than m (modulus) or e > φ(n) ? I wonder about choosing public key exponents (e) because the most information on the internet or ...
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Does higher key sizes correspond to a higher security parameter?

If a system provide n bits of security, it is known that the best possible attack against the system would be 2^n (security parameter). However, why are the key sizes of some cryptosystems much larger ...
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Construction of Blake2 and Cha Cha

Recently, I was reading about Blake2B and its properties regarding randomness and security, and its connection to Daniel Bernstein's CHA CHA digest. As a budding cryptographer, I find it doable to ...
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Password Manager Architecture and Design

I'm working on a local, client-side password manager. I want to hash a master password with argon2 to store it safely in an SQLite database. This will be how a user could login and be authenticated. (...
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Using asymmetric encryption + key rotation, is it possible to make an extra obfuscation layer?

I'm building a service, that works as the cipher and decipher for instant messages. It works by following the following steps: The sender encrypts the text(not long, mostly chatting messages) using a ...
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Weaknesses of AES-GCM [duplicate]

Besides the limited nonce size of 96 bits, are there any other weaknesses to the GCM mode of AES? I am creating a password vault and am trying to narrow down my options of encryption schemes. Also, is ...
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Cryptography to tackle deepfake, proving the photo is original

Deepfake technology has become very difficult to tackle due to sophisticated machine learning algorithms. Now, even when a journalist or bystander provides photo or video evidence, the culprit denies ...
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AES-ECB attack encryption audio fie

I got two audio files one is encrypted and the other file is a part of the plaintext. I want to extract all the plaintext. I am using the AES-ECB mode, the size of the block is 128 bits and the start ...
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Is there any way to measure entropy of encryption algorithms in python?

I am new to cryptography and I am trying to find a way to measure ciphertext entropy of encryption algorithms such as AES, Chacha20, etc for a school project. Is there any way to do it on Python? I ...
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Is it possible for XTS to use two different key sizes?

As an example could be XTS with a 512-bit key that treats the key as one 128-bit key and one 348-bit key. As to why I'm asking it's because XTS runs on one large key that it treats like two keys. ...
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Can someone help me in construction of a one time unconditionally secure MAC scheme? [closed]

The MAC scheme should not be using any primitives like PRG, PRF or PRP. Ok what could be possible solution if we ignore the statement "
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Why is the adversary in IND-CCA allowed to make encryption queries?

IND-CCA is an abbreviation of "Indistinguishability under chosen ciphertext attack" and generally, an adversary carrying out the chosen ciphertext attack is given a decryption oracle only. ...
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Is signature same as hash value encrypted with the private key in openssl?

Computing the signature of hello.txt file which has the text hello in it, here is done in two steps: ...
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Metrics for difference/error of output and ideally output

I'm working in some homomorphic encryption for my Ph.D. but I'm not of the field... So I'm possible going to ask a really simple question that I'm struggling to find an answer on the internet. ...
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For Symmetric Cryptography, why is it considered more important to safeguard a key than the function/algorithm for encrypting/decrypting a message?

As stated for the question above here's an analogy: You are a robber looking for a house to rob with two different scenarios that might occur. 1. You have a key that you know belongs to a house and ...
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A semantically secure encryption scheme can not preserve the length of an encrypted plaintext

A semantically secure encryption scheme can not preserve the length of an encrypted plaintext. How to prove this? or are there some methods that can be used to obtain such information from a semantic ...
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Hard to guess ciphertext

Is there an encryption scheme where it's hard to guess a valid ciphertext without knowing the key and the scheme is CPA secure?
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Does sending encrypted hash inside message compromise security

This might sound like a naive question (And maybe it is (It's an early morning Saturday thought, so there might be some clarity of thought missing)). Suppose we havea protocol that sends messages as ...
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Reorderable encryptions [duplicate]

Are there any two encryption function(s) where encryptB(encryptA(data, keyA), keyB) == encryptA(encryptB(data, keyB), keyA). The two functions may be related or ...
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Equality between encrypted hash of data and hash of encrypted data?

Are there any cryptographically strong hash function and encryption function(s) where hash(encryptA(data)) == encryptB(hash(data)). The functions ...
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Proving 2-way nesting security

I recently came across the theorem about $n$-way nesting. It states that if $\mathcal{E}=(E, D)$ is semantically secure, then $\mathcal{E}$ is secure for $n$-way nesting. I'm trying to prove the ...
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Is there still a place for obfuscation (secret algorithms) in encryption?

As far as I know, the Second World War was won on codes that used obfuscation, not open source. These were also used during the cold war. For general use (not large companies with hundreds of ...
Zonnkq Shad's user avatar
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What is meant by software and hardware implementations of cryptograpic schemes? How to do it?

I have read many cryptographic papers or articles where I have came across about the software and hardware implementation for the cryptographic algorithms. I want to know how its been done. Is there ...
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Decryption only on a specified future date?

Are there any encryption protocols or services that are time based. I.e I can encrypt something now and it can only be decrypted on or after 01/01/2100. Like a digital time capsule. The only way I can ...
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Java AES T-Tables Implementation

I am trying to implement an encryption function that uses the AES T-Tables implementation. I am quite sure that my roundKeys are correct. I also know that the initial round key addition in the ...
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1 answer
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Would encrypting several layers of a filesystem be a waste?

I've been thinking about ways to improve the security of my data stored and backed up using the "3-2-1" method. Moreover by using several layers of encryption to encrypt and decrypt a ...
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Zero-Knowledge Proof of Encryption with a Specific Key

Short version: Given a hash of a plaintext, a public key, and a ciphertext (but not knowing the original plaintext), is there any way to verify that the ciphertext is the plaintext after being ...
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Is the SNI extension signed in TLS 1.3?

In TLS 1.3, and since the server signs the entire handshake messages including the server hello message, in this case, is the SNI extension of the client hello message, is it included in the content ...
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Sagemath help: Introduction to Lattices

Hi im doing a problem from the Chapter Lightweight Introduction to Lattices in "Learning and Experiencing Cryptography with CrypTool and SageMath" I'm curious if my implementation is wrong ...
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Does BearSSL Library Support ECC Encryption/Decryption Functionality?

I'm researching cryptographic libraries for a project I'm working on, and I'm particularly interested in the BearSSL Library due to its lightweight nature. But I'm not sure if it supports ECC (...
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