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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Cracking an XOR crypt with a know key length

I'm trying to crack a crypt with a known key length. I deduced that the operation made was a hex XOR. Here is the crypt: ...
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A perfect key exchange similar to the One Time Pad

The one time pad is unbreakable because each message could be one of many, and each one is equally likely. Is it possible to do this with a key exchange? (So if someone records the key exchange, there ...
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is SHA512 with 256 bit set is similar or same as SHA256?

I'm new in Cryptography, if i will use SHA512, but only with 256 bits, is it equal or similar to SHA256? I'm trying to understand if there is a way to use SHA512 as SHA256
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Is there a name for an encryption scheme that do not return $\bot$ when a different key is used during decryption?

Given an encryption scheme $\Pi = (G,E,D)$, either public or private, is there a name or a property to emphasize that for $c\gets \Pi.E(k,m)$, where $k$ is a key and $m$ is a message, we want $m^\...
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Need clarifications AWS Cloud HSM architecture [closed]

My apologies for the long post. I read on AWS docs that, when keys are generated using java keytool, the certificates are stored ...
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How to exchange keys in JWT between server and client and between shared servers?

I'm not sure I have a full understanding of JWT when it comes to the signature. The signature, as I get it, validates to the server that the header/payload that was transfer from the client is legit. ...
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would compressing encrypted data and compressing digital signatures bad for security?

I understand that compressing encrypted data and compressing digital signatures are not efficient because they are most likely incompressible. But in my application encrypted data and digital ...
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Publishing a message with a computationally enforced delay [duplicate]

I'm looking for a way to publish a message, so that it will only be publicly known after some time (let's say a few minutes). Even I shouldn't have the power to prove what my message was, before this ...
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Which ciphers have been defined that use the Keccak sponge?

There seem to have been defined multiple ciphers using the Keccak sponge as building block / primitive. These seem to have escaped public attention, possibly because they have not been standardized ...
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In a PGP like Application , would compress and encrypt leak information

would compress and encrypt on data comromise security for PGP like application, would it be secure for use in Encrypted Messaging? I have heard its safe for data at rest encryption , i have heard ...
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About the public key in Digital Signature

Please I do have a question as you know to sign a message the sender must first of all calculate the hash of the message and then encrypte it using his private key and then send it to the reciver and ...
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Is there any way to break the AES encryption mechanism? If yes, what is the most secure encryption mechanism? [closed]

I've been studying cryptography recently and from what I've seen, AES-256 and AES-128 seem like some of the best encryption mechanisms. Are these encryption mechanisms not secure compared to others ...
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Does having multiple salted hashes lower pre-image resistance?

A common method to mitigate the effect of rainbow tables is to add a string to the end of the user password before hashing, a process known as salting. However, let’s say for example that someone uses ...
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Asymmetric encryption of transaction log file: is RSA the correct algorithm

I want to produce a transaction log that is encrypted while being produced. I'd prefer asymmetric encryption. It is possible that my program will terminate without writing any closing blocks, so my ...
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Is this property generally true for AES-128?

Let $E_{k}(P)$ be the AES-128 function with key $k$ and plaintext $P$, both 128 bits. I want to know if the following property is generally true for AES or if have I stumbled upon a special set of ...
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Designing a scheme to store encrypted data on a backend

My goal is to design an encryption scheme for the application so that the backend stores encrypted data and the whole process of encoding and decoding happens on the frontend. And you can be sure that ...
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How is DES used with CBC?

I'm reading our school's notes for cryptography, and it does a good job explaining CBC and DES in detail, but it fails to provide good information on how they are related. From what I've researched so ...
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Significance of theoretical weaknesses?

What is the significance of theoretical weaknesses? Any real life incident where a theoretical weakness was ignored and later it compromised the system? Whats the dividing line between theoretical and ...
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How to decrypt a RSA plaintext given a public exponent e and a RSA modulus n

I am doing a RSA cryptography task where I need to decrypt a ciphertext but I am only given the ciphertext ,c, a public exponent, e, and a RSA modulus, n, which has two prime factors p and q such that ...
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Use same key k in deterministic counter mode to encrypt two different plaintext

What goes wrong if we use the same key k in deterministic counter mode to encrypt two different plaintext messages m0 /= m1. It is not true that c0 = c1, because we XOR output of m0 with input of m1 ...
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AES subkey calculation not working for subkeys beyond 0 and 1

How should I generate the remaining keys when performing subkey generation in AES encryption? I generated keys 0 and 1 first, but the other keys I generated later were wrongly generated, so what steps ...
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Confirming understanding of security protocol modelled in Scyther

In university, I'm currently learning how to use Scyther to model security protocols. Currently I am trying to understand what is happening in an example protocol given to me which is: ...
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In RSA, what if the message 'm' to be sent equals to one of the 2 prime numbers 'p' and 'q'?

In RSA, one of the math background is: m ^ φ(n) % n == 1, where m is the message to be sent, ...
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What are the best known cryptanalytic attacks against AES-128 with 9 rounds?

What are the best known cryptanalytic attacks against AES-128 with 9 rounds? I found many such attacks on AES-192 and AES-256 with 9 rounds, but not for AES-128 with 9 rounds. Are there any ...
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Zero Knowledge Proofs for Microsoft SEAL (Homomorphic Encryption)

I am working on a system involving multiple parties performing homomorphic cryptographic operations using Microsoft SEAL (BFV). Because of the nature of the system, it would be preferable for the ...
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Possible plain text needed on a congruence modulo - based encryption

Suppose m is a positive integer converted from the plain text in bytes. And there are two positive integers a, ...
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OpenSSL AES-GCM says 'bad decrypt', other block modes work fine?

If I do a simple encrypt and decrypt test like so: ...
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In RSA, how to calculate the private exponent 'd', after choosing 'e'?

Seems there are 2 ways: d = (ϕ(n)*k + 1) / e In this case, need to choose a proper integer k. Question 1: How to choose k, just try positive integers start from 1, ...
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Old openssl version does not support -iter or -pbkdf2, how does it derive the encryption key for AES?

When using openssl or libressl to encrypt or decrypt data with AES, I typically specify ...
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About validity of public key encryption

Hi I am searching for public key encryption schemes that if not encrypt with the desire public key the encryption would not be valid e.g if having a pair of key pk/sk, and want to encrypt message m ...
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How does openssh actually choose the public exponent 'e' when generating a RSA key?

What I've read: https://crypto.stackexchange.com/a/12256 https://crypto.stackexchange.com/a/20328 Seems in practice, will first choose an e, then choose the 2 big ...
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How to proof Two CipherTexts holding same value with Zero Knowledge Proof?

I am a beginner in cryptography. I wonder is it possible to create by Zero Knowledge Proof, to prove Two cipherTexts that are encrypted by same Public Key with Paillier Encryption have the same value ...
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In client-side encryption, if the server provides the encryption/decryption methods, is it really "client-side"? [migrated]

Google recently introduced the client-side encryption functionality in several services of Google Workspace (see https://support.google.com/a/answer/10741897?hl=en). The purpose of client-side ...
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How can I encrypt signature with RSA? [duplicate]

I understand that from security perspective the sign-then-encrypt approach is the best. I tried to implement it in Python with the cryptography package and I got this error: ...
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Cascading Streams From the Same Cipher

Does encrypting plaintext multiple times with the same stream cipher but independent keys increase security? If each key is n-bits, and the cascade uses m-streams, could this be considered mn-bit ...
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Is a single digital signature (ECDSA) of an encryption key (AES) enough to verify the legitimacy of all encrypted messages?

I have an encryption scheme set up with a client and server that utilizes AES 256. What I am curious about is whether or not all information sent from the server to the client can be verified as ...
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What does it mean that DES algorithm was meant to run on hardware?

According to sources that I've read, it says that DES is not suited to a software implementation and that it is better suited to hardware, what does this mean?
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why XOR is recommended/Used in every paper I read for encryption and decryption stream cipher?

Stream ciphers use a deceptively simple mechanism: you combine the plaintext data, bit by bit, with “key” bits, using the exclusive or operation. Why can't I use other opeartions such as NAND, AND, ...
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Is it possible to encrypt data with two public keys?

Can we encrypt data with two public keys and the encrypted data only needs one private key to decrypt once encrypted?
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Can we change the irreducible polynomial of AES algorithm?

The AES algorithm uses the irreducible polynomial. Consider x^8+x^4+x^3+x+1 for multiplying with a MDS matrix for encryption ...
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What is the simplest way to implement data encryption for Raspberry PI project that communicate through Bluetooth? [closed]

I have developed a project based on Raspberry Pi that communicates through Bluetooth with Android application, My idea is to enhance its privacy through encryption. So, I've tried ...
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Is there a 32 bit block cipher that is also a permutation over all 4bn elements?

Purpose: I'd like to shuffle a file system's blocks without loosing space so I thought if I formatted the disk to have exactly 2^32=4bn sectors, then a secure cipher with 32 bit wide data blocks could ...
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Is 7-Zip Encryption really secure? [duplicate]

Is 7-Zip really a good encryption tool? I wonder what kind of encryption is used in 7-zip. I see most people using 7-Zip. Just curious about what extent it is safe.
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Encrypting messages with two different public keys

The problem I have is next: There's the centralized DataBase app which has its own private key and sends its public key to its customers. Each customer has its own private key and should be able to ...
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Keyspace in Encryption using Chaotic Maps

I wish to encrypt an image using Logistic map. A Logistic map can be specified with the Equation: $$x_{n+1} = r\,x_n (1-x_n).$$ Now, according to the Kerckhoff principle, the entire system's security ...
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In RSA, why are there multiple possible private keys, and even the public key itself that can be used to decrypt the message?

This is with reference to Eddie Woo's video on RSA. He uses the prime numbers '2' and '7' to make the product, n=14. He chooses the public key to be '5', the only possibility. However, many numbers ...
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Zero-knowledge data storage with peace of mind. MAC/Encryption with two keys?

Background Bob's goal: Receive data E = E(D) (encryption of D) from Alice that he knows for sure is encrypted and that he can't possibly decrypt (without brute force). This gives his data backup ...
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How to Ensure Security in a Gaming Peer to Peer Network

I've been recently thinking about building a c++ poker game that would let players to play over sockets in a peer to peer network. However I do not know how security would be ensured. I was thinking ...
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Generating an IV from a constant seed and predictable salt larger than the value space of the IV

I am planning to encrypt multiple values using a 16 byte IV that I'm generating from the below scheme. My seed is a 32 byte ...
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Encrypting an IV with XEX using a block cipher and XORing on the plaintext: Is this scheme valid?

I had an idea to make XEX mode parallelizable at CPU level. Let's suppose I take an IV, XOR with random data, encrypt, XOR again with another data, and XOR on the plaintext Would this encipherment ...

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