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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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 = (...
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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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Got a Cipher that I'm stuck on! [closed]
Been trying to learn cryptology, and found this one I just can't solve:
.- .. -.-- -. .- / --. -.- .-. -.-. - / . .-.. ..- --- .. / ... --. .- . . / .-.. .-.. ... --- -. / --- -.- --- -. ... / -. .- .-...
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In openssl, if I decrypt using a wrong password it just tells "bad decrypt" without showing the output. Is there a way to show it anyway? [closed]
I encrypted a sample test file using:
openssl enc -aes-128-cbc -in test -nosalt -out encprova.aes128
Then, to decrypt:
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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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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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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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How to require possession of arbitrary data to decrypt a file?
I have pairs of files A and B both of arbitrary size and contents (for any pair of files, A could be significantly larger than B or vice versa). I want to be able to 'encrypt' A in such a way that I ...
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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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Best way to encrypt sensitive data on server with HSM and symmetric keys
I need to store sensitive data (like customer photos) in a SQL database in the most secure way in case of security breaches. The data won't be accessed by the clients, only by internal processes that ...
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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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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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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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Differential Cryptanalysis in Combining Two Ciphers [closed]
If I know that a differential $\Delta$$X$$\rightarrow$ $\Delta$$Y$ is coming through one cipher with probability $p_1$ and another differential $\Delta$$S$$\rightarrow$ $\Delta$$T$ is coming through ...
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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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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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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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Difference between Key Scheduling and Key Generation?
I am a little bit confused in the terms i.e Key Scheduling and Key Generation. What is the actual difference between these two terms? According to Wikipedia, the terms are described as:
Key ...
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Why does the distribution of BFV's sk use $R_2$, and what are the disadvantages of using $\chi$?
Instead of sampling $\mathbf{s},\mathbf{u} \gets \chi$, we will sample $\mathbf{s},\mathbf{u}$ from $R_2$, i.e. the norm $||\mathbf{s}||=||\mathbf{u}|| = 1$.
$\cdots$.
The security implications of ...
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Creating nested messages in OpenPGP
I need to create a nested message in OpenPGP (my understanding is that the protocol itself should support it).
Let's say I have Payload ("Time in Lordran is ...
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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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Reencrypting in Homomorphic Encryption
I am getting started with Homomorphic Encryption libraries. I am trying to port a codebase written in Python to Haskell. I see that there is a re-encryption operation happening in one part of the code....
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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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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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Did Phantom Secure use the same level of encryption as WhatsApp? [migrated]
I've been following a story for some time now about a high-ranking Canadian official who was charged in leaking operational data to the makers of Phantom Secure. There was a very deep level of concern ...
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Which solution is the more protected?
I am wondering which of these two solutions is better for security on the long run. The problem is:
Alice and Bob exchange a secret key/private key. Then they go far away from each other and never ...
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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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Using the OTP and RSA compared to only using the OTP itself
To use the OTP with RSA, I implemented the one-time pad first for only one time, and then I used the RSA algorithm to encrypt the message.
For the RSA algorithm, I pick $p$ = 2143 and $q$ = 3257, ...
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How to crack base conversion that uses a secret symbol set?
I've looked at this crypto SE post but it doesn't address the how of my question.
I've been interested in cryptography for some time. I wrote a relatively basic cryptosystem in Python that uses base ...
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Suitable cipher to encode/decode paper passwords [closed]
I have 10 passwords that I want to keep all the time with me in my wallet, so I need to encrypt them somehow, in case it gets stolen.
The passwords have upper/lower characters, numbers and special ...
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What is of hybrid Indistinguishability
Why we need to use hybrid Indistinguishability to hiding function or message in revocable predicate encryption using functional and attribute based encryption?
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LWE with a binary matrix A
In LWE, we know that given reasonable public parameter $A\in \mathbb{Z}_q^{n\times \lambda}$, secret $s\in \mathbb{Z}_q^{\lambda}$ and noise $e\in \mathcal{X}^{n}$, random $r\in \mathbb{Z}_q^{n}$, $(A,...
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How can a hash function be suitable for hashing passwords, but not for deriving encryption keys, and vice versa?
Not being a specialist in this field, I am nevertheless constantly trying to keep up with which methods are being considered secure for storing passwords and for encrypting data.
During my research ...
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How to encrypt a message such that it cannot be decrypted before a certain time? [duplicate]
Suppose you have a message $m$ and you want to design a protocol that produces an encrypted message $c$ such that it cannot be decrypted before a certain time $t$ has passed from the encryption.
How ...
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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 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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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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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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How does Microsoft's BitLocker Recovery Code work?
I don't trust Microsoft BitLocker because it is closed source, which makes it so people can't audit it. But now I'm really interested in how its recovery code works. In my own knowledge, encrypted ...
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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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