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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Fast key exchange algorithm in hardware with small key size

Which asymmetric algorithm will be best only for key exchange to set up communication using symmetric cryptographic algorithm. Comparison should be in term of speed, key length and their hardware ...
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Any number-to-number cipher?

I am curious (not technically informed) if the number-to-number cipher is common/useful in cryptography. Imagine, we want to cipher integer y to integer ...
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Are there any best practices/recommendations for/against using client-side password hashing?

I do not mean generating a hash on the client side and then storing it in the database directly. I found a few questions with similar theme, but most of those answers assumed a scenario where ...
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Asymmetric Encryption Using Existing Secret Key

I'm using Python to build a system in which users (accounts on a blockchain: defined by a public key and a secret key) need to communicate with each other securely and I think asymmetric encryption is ...
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Would a celestial cryptographic system be useful in practice?

I posted a question recently about whether a celestial body could be used in cryptography. I got many fantastic responses explaining how the celestial object could be used to generate a common ...
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Could celestial objects be used in cryptography?

If it were possible to receive a string of numbers from a celestial object (by anyone on the Earth who knows which object to look at, and what time to look) could this be of any use in cryptography? ...
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Using two keys and two messages

Is the following cryptosystem possible: There is an encryption function: encrypt (k1, k2, T1, T2) = M, where T1, T2 - two plain texts, with the same number of characters, k1, k2 - encryption keys of ...
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How To Read Encryption/Hashing Notation

This is very basic, but what I'm wondering is: I have a few notations of hashing/RSA encryption that I'm unsure of when reading. PKE(PW, K) With PW representing a password, K representing a 128-bit ...
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Chaos-based AES, is it secure?

In the link below, the author uses the aes as a basis for his cipher. In his words: The thesis investigates and explores the behavior of the AES algorithm by replacing two of its original modules, ...
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What is the best attack on AES with a half known key?

If I have a 16 bytes key and I encrypt a text block (1KB) with AES, and the attacker knows half of the key (let's say the first half), how does it weakens the encryption?
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How difficult is it to break unknown encryption?

I found this post on Reddit and was wondering if anyone could provide a more detailed explanation/answer: Lets say I find a hard drive in a trash can along with a sticky note that says "AES-128, ...
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What is the easiest encryption/cipher to brute force?

This is just a casual exploration of what could be effectively the worst possible block cipher, but I think it has some educational value on how ciphers work. I've been reading about unicity distance ...
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What benefit is gained when combining AES GCM/GMAC with ECDSA?

This is a real world question (and as I'm not an expert in cryptography I have only some basic knowledge in terms of just using it, not a deep understanding how ist works under the hood.): A system ...
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Is it Possible to Prevent/Mitigate Modern Encryption of Data by Using A Known Signal?

Given a block of data, say THE+ QU+ICK+ BR+OWN+ FO+X J+UMP+ED +OVE+R T+HE +LAZ+Y D+OG Is there any method of encryption that will make the knowledge that the '+' ...
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RSA use prime p as public exponent

I've got two 1024 bits prime $p$,$q$,and $n$ = $p$ * $q$. now I know the result of $ c^{p} \quad mod \quad n = x$,also the value of c is given, I wonder if it is possible to factorize $n$.
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Can we determine the size of n-bytes before encryption by AES-128?

I am writing a program in python to encrypt files. This program takes subsequent 1024*1024 (1 mebibyte) chunks of data from a file and encrypts it using AES-128. This is performed in a loop until all ...
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Crypt-analysis for finding information hidden in images?

I was wondering if anyone is familiar with any historical aspects (as to whether someone was able to) for discovering code using images on the web as a transport method ? As in hiding byte values in ...
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Can knowledge of algorithm be used to reduce anonymity?

This is a bit of a crazy hypothetical, but I think it best illustrates what I'm looking to ask. Scenario + Question There's a distributed & decentralized cloud storage network that's starting to ...
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Can we pick which key is private or public in asymmetric encryption? Do the keys actually encrypt and decrypt a cipher text?

Could you help me better understand how the key-pair works in Asymmetric encryption? I'm studying cryptography at the surface level first. While reading multiple texts and talking with colleagues I'm ...
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Is there a form of cryptography where the key is derived from the plaintext

Imagine you are building a shared remote storage system where you send everyones files to a central storage, but you want to de-dup the files between multiple users so we don't store the same file ...
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Verifying result of (EC-)Diffie-Hellman

I received a public key by JSON. For the example, I have 4 keys: 2 public keys and 2 private keys. ...
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Proof that someone has access to a private key whose public key is part of a known group

I'm a crypto newbie and hoping to get pointed in the right direction. I've seen some related questions like this but none that satisfy my requirements. Let's say Jane's Forum is a large community, and ...
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Asymmetric encryption scheme with the shortest output for encrypting 1 byte of information

Imagine that one needs to periodically encrypt very short messages (i.e., a boolean Yes/No, a single byte, or 3-4 bytes in the worst case). We assume that there is no session, and we just need to ...
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Does Salsa20/ChaCha20 still provide Integrity when Encrypt Bitmap?

Forgive me for this question. I have an idea to encrypt *.bmp bitmap files using ChaCha20/Salsa20 without Poly1305. This is just a simple program, where I can encrypt *.bmp bitmap images, with the ...
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Encryption of data with multiple possible decryption keys

I'm new to the Cryptography Stack Exchange, so my question might be very naive. What encryption algorithms are out there that will allow different decryption keys to decrypt the same piece of ...
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Mifare Classic, authentification protocol question

Thanks to reverse engineering papers on Mifare Classic, one can study the authentication protocol. However, I have a problem understanding how it works. In the above document, after the reader ...
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Is it practical to build a symmetric encryption cipher that needs the changing of the "main" key for each plaintext?

I read about an encryption cipher that needs the changing of the "main" key for the encryption of each plaintext. Sometimes this change depends on the plaintext and is done automatically. ...
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Encryption using N number of keys (PKI) and decryption using M out of N Keys

On a tendering portal, I want to encrypt the value of the submission using N number of public keys (PKI) and later on want to decrypt the same information using M out of N number of private keys (PKI)...
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What is the term to describe the combination of ciphertext, IV and authentication tag?

Authenticated encryption with associated data, such as AES-GCM, will take as input: IV, optional associated data, plaintext and key. A ciphertext and an authentication tag will be produced. Is there a ...
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Are there any estimates for the spectral radius and distribution of eigenvalues for the AES, DES, etc round functions?

Suppose that $F:K\times X\rightarrow X$ is a function such that for each $k\in K$, the mapping $F_{k}:X\rightarrow X$ defined by letting $F_{k}(x)=F(k,x)$ is a bijection. Suppose that $F$ is the round ...
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Designing your own Algorithm

I have been told to design my own algorithm as a college assignment. What I could have come up with was a random cipher. For example: Suppose my plaintext is: AND ...
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Extracting genome from a Ciphertext [closed]

Is it Probable to extract the ciphertext's genome and Visualizing it ? Converting this: ...
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How does WhatsApp synchronize messages between phone and web browser or computer application?

I would like to learn about message synchronization process of whatsapp cross platform applications for same user. I've checked WA whitepaper and couldn't see any explanation. I'm using both WA WebApp ...
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What does it mean: Hardware vs software implementation of a cryptosystem

While reading some cryptography papers, I passed by some new terms like the hardware and software implementation of encryption systems. The question: what are the hardware and the software ...
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Proof that a message is signed by a member of a group

I'm a newbie at cryptography. Here is my question: Alice makes a list of people: Bob, Carol and Dan; Alice gives a unique secret key to every member on the list, so they can uniquely sign messages; ...
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Which is best: RC5, RC6, CAST-128, LOKI97, or MARS? [closed]

Considering speed and security, which is best: RC5, RC6, CAST-128, LOKI97, or MARS? What does the scoreboard look like? (I'm asking about the abstract math concept, not related to any code ...
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AES and the Feistel Structure Used Together?

In Dual Watermarking in Tele-radiology using DWT for Data Authentication and Security, the authors wrote: The encryption process uses the Feistel structure consisting multiple rounds for processing ...
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How can I do cryptanalysis on a chaos-based cipher?

I have been reading about chaos-based cryptosystems. Every designer claims that his design is a secure system without much cryptographic analysis; however, it turns out that this is a false claim in ...
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Is chaos-based encryption legitimate?

Is chaos-based encryption a rigorous discipline? And why there are objections to it within the cryptography community? And why are many of its cryptosystems weak? And does it has a promising future? ...
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Weakness of XORing random bytes with secret key

Side A generates 16 (high quality) random bytes and performs XOR with a 16-byte secret key, then data transfers to side B, where the same secret key is used to recover the original 16 random bytes. Is ...
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RSA DECRYPTION when N gives only one prime number

I am getting only 1 prime factor to some power if i factorize N for RSA decryption. So, in this case what will be the value of P and Q. P will be that one Prime Factor and then there is nothing left ...
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180 views

Decryption of an unknown cipher

How can I identify the cipher that encrypted the data shown below? I'm very new to this field, so I am not sure. For example: How does one know which cipher is used in the following line? How can one ...
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225 views

Decrypt RSA with known public key and modulus and the range of dp

How to decrypt RSA while given $e$,$n$ and the range of $dp$ ? ...
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156 views

Elliptic curve bilinear pairing parameters for 80-bit security level

I am reading a paper based on elliptic curve bilinear pairing groups. The author has defined the size of private key, public key etc in terms of $|\mathbb{G}_1|, |\mathbb{G}_2|$ and $|\mathbb{G}_T|$. ...
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Managing master keys used in PBKDF2 and HMAC (store, rotate)

My use case: I have few master keys, I use each for a specific operation (e.g. one for encrypting user's data and another for creating JWT signatures etc...). I use these master keys in two specific ...
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Should I protect the salt before storing it in a database or use a pepper (secret salt) instead?

If I protected the salt or used a pepper (secret salt) and an attacker got access to the database he can't do a rainbow table attack on a targeted user (a famous or important person). Should I use a ...
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What uses are there (if any) for asymmetric message encryption?

What uses are there (if any) for asymmetric encryption of a message, instead of hybrid encryption? Specifically, I'm not considering asymmetric encryption of a symmetric key (eg old TLS RSA key ...
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Comparing two private values and extracting the ciphertext corresponding to the minimum value

How can I solve this problem: I have a directed graph of nodes that can be malicious and all of them have a private value. Consider a node "B" with private value "BPrivateValue = b&...
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Does asymmetric order-preserving encryption exist?

As I understand from this post, mapping from plaintext space to ciphertext space is the fundamental point of all order-preserving encryption. So the only way that we let someone encrypt an arbitrary ...
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Can CPA secure scheme be converted to CCA secure?

I would like to know if there are some methods or techniques that can convert a public key encryption scheme from CPA secure to CCA secure?

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