Questions tagged [decryption]

In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Only authorized parties can decipher a ciphertext back to plaintext and access the original information.

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AES Key vs RSA Key

I am compeletely new to cryptography and recently tried to understand it a bit more thoroughly. My question is: How does the Generation of keys differ in the case of AES and RSA. I understood, that ...
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Use of custom DH parameters for TLS decryption

There are several ways to decrypt TLS e.g. in an enterprise environment. I did not see using "backdoored" DH parameters being mentioned somewhere though according to my understanding it ...
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Comparing different cipher text all saying the same thing

How can I compare different cipher text? When deciphered, say the same thing. I would like to find out the ciphering method. Any help would be appreciated. Thanks. The primary code needs to be a 8 ...
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Are there any schemes for support time-limited decryption that are not based on P2P or TTP models?

Time-lock encryption is a method to encrypt a message such that it can only be decrypted after a certain deadline has passed. This sounds like time-lock decryption. I was wondering if the inverse with ...
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RSA: is it possible for the cube root attack to fail even if e=3?

I've came across an example where the e value is three but no matter what tool/script I try, I can't decrypt it. I'm wondering if the ciphertext and n is super super large, is it possible to crack it ...
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RSA: The algorithm aside, how are we turning a string into an int and vice versa?

Let's say that I want to encrypt the file plain.txt. The very first step is actually to turn the contents of that file (lets say it only contains the string "...
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How to Prove Correct Decryption in ElGamal Cryptosystem

I am working on a project that uses ElGamal cryptography using multiplicative notation. The project is an internet voting implementation that uses the cryptosystem to encrypt the received ballots, re-...
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83 views

Decrypt AES-128-CBC encypted partial RSA Key

I am given a private RSA key, which header indicates that it is AES-128-CBC encypted. Note that the last ten lines of the key are missing. (This is part of an educational task.) ...
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Is there any fundamental difference between the block cipher operations encryption and decryption?

Is there any fundamental reason to designate one direction of a block cipher as "encryption" and the other "decryption"? Or are these arbitrary choices? Or perhaps practical ...
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Pretty much confused about pretty good privacy-:

Authentication-: I understand that authentication is basically digital signature. But what I don't understand is how it has been explained here specially the RSA key part. It is leading me to huge ...
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Don't know how to approach this problem, or where to start. Finding an adversary to a hiding and binding game

I have this problem: I also have the python version of this problem here: ...
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How to decrypt a file using RSA and just a public.pem file?

I have an encoded file and a public.pem file. Is it possible to decode the file using the public.pem file or do I have to start looking at private keys? I tried https://github.com/Ganapati/RsaCtfTool ...
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Where to store salt for PBKDF2 and initialization vector for AES via WebCrypto

I would like to build secure notes via javascript and webcrypto. I have found the possibilities to generate strong key via PBKDF2 and encrypt data via ...
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Teaching AI a cryptogram and asking it to solve a similar cryptogram on its own

Say that 1 cipher and another are known to hold some form of correlation. Would it be possible to teach an AI one language through the training of a model and allow it to make make predictions on ...
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Example of exchanging information

I am searching for a simle model that can simulate the following procedure. Suppose that $i$ and $j$ are two agents that each one obtains her state dependets signal $s_i(\omega)$ and $s_j(\omega)$. ...
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How does knowing the factors of the key help me decrypt?

I recently started learning about cryptography and its Quantum aspect and I came across Shor's Algorithm (which solves the following problem: "Given an integer N, find its prime factors"). I ...
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Vigenere Decryption with key length

I have a question. If I have 2 ciphertexts given and the same key has been used on both. They key lenght is the same as the plaintext and cipherrtext length. How do I decrypt them and find the key. So ...
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Is it possible to get the SHA256 hash collision with partial known data

I have a text sentence that consists of 448 digits [0-9] [a-f] (in HEX format). This text sentence is partially cut off, but I know the middle, and the beginning ...
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Can you decode aes by hand if you have the key?

I made a javascript aes encryption program and I do have the key to what I encrypted. Is there a way to use that key and figure out what was encrpyted without help of a program? I encrypted "...
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RSA implementation not working with large values for plaintext [duplicate]

While implementing RSA encryption/decryption (using python), the plaintext doesn't match with the decrypted ciphertext for large values of plaintext. Works fine for smaller values for plaintext (...
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What is the best way to save ChaCha20 Nonce in Cipher-Image BMP file?

I have a question about ChaCha20. As far as I know ChaCha20 is a cipher algorithm that uses 4 inputs: Key (secret) Constant (not secret) Block Number/Counter (keystream block number) Nonce (random ...
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1answer
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Read ECDHE traffic with Wireshark or the like

There is some https traffic from a specific server (which I have the certificate and private key) that I need legitimately be able to read. This traffic doesn’t come via browser so besides the ...
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How do I progress with cracking this monoalphabetic substitution cipher that ignores natural word divisions?

Having some trouble cracking this cipher (this is part of a homework assignment for a cryptology class) I've looked at letter frequencies but I'm not sure what else there is to help me. Given the ...
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Getting the plaintext encrypting the ciphertext

Context: an encryption game from overthewire (the link to it: https://overthewire.org/wargames/krypton/krypton6.html, also good for more info) where given the ciphertext, one must obtain the plaintext....
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Encrypt private key and decrypt with the public key

Is it possible to encrypt with the RSA private key and decrypt with the RSA public key(not for signature) The task is that I have to encrypt the data with a private key. Transfer this data to another ...
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Decrypt a ciphertext knowing of a pattern of key repetition

I have two ciphertexts (I do not know which encryption algorithm was used to create them) which both starts with the same 3-characters long word. This led me to believe that the same key was used for ...
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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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FOR AES GCM decrypt function, Does the output(PT) depend on Tag value(T)?

According to spec, FOR GCM decrypt function input is IV, A, C, and T. As mentioned below: 5.2.2 Authenticated Decryption Function Given the selection of an approved block cipher, key, and an ...
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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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My fernet key "expired" what now?

6 months ago i created a bot that basically stored every users data in json format in different text files and i had a fernet key. I basically didn't touched it for like 2 months now, because it's a ...
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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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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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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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decryption in IDEA if the encryption was made without the output transformation

I'm implementing IDEA encryption and decryption and I'm trying to implement it in different variants(e.g if we didn't do the output transformation or if we don't do full 8-round encryption). I got the ...
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1answer
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What is the correct order of operations for one-time pad cipher when using subtraction and mod 10 arithmetic?

What would be the proper order of operations for OTP encryption/decryption when using subtraction and mod 10? E.g. P - K = C or K - P = C Most of the sources I have seen do not cover this topic or I ...
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Where exactly do you add the zeroes to a URL in a padding oracle attack? Also, how would you decrypt a file this way?

I have been studying various crypto attacks, and one of the attacks that I have recently studied was the padding oracle attack. Now, I mostly understand it, but there is one aspect of the padding ...
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Completing RSA Encryption

Being new to cryptology, I'm trying to understand how I would complete RSA encryption by hand. I can only follow the formula so far before becoming very confused. I want to encrypt the value "123&...
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How can I go about decrypting some files that were most likely encrypted using android's file-based encryption?

I am looking to try and decrypt some files from a phone that I no longer have. I've tried to provide some background information here for context purposes. The files in question were backed up from ...
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Extra bytes when decryping with OpenSSL

The string is encrypted with the following properties (using C#): myAes.Mode = CipherMode.CBC myAes.KeySize = 128 myAes.Padding = PaddingMode.PKCS7 myAes.BlockSize = 128 myAes.FeedbackSize = 128 Key: ...
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Cryptography Challenge [closed]

I have been messing around with cryptography (for recreational use) and I have created my own function that encrypts things for me. Now, with that being said, I freely admit that I am by no means an ...
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crypt algorithm by a vectored key and the error is Proportional to the difference between input key and real key

I want to find an crypt algorithm which provides the functionality described below. Given a key (a vector Vkey) and a data (an image), use this key to encry the image; the encrypted image can not be ...
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Am I Doing RSA Correctly?

I am trying to figure out how to complete RSA manually. I am trying to encode a simple block message (Mi). I used CrypTool to determine the encryption. When I "manually" computed the ...
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It possible to encrypt .bmp bitmap files using Stream Cipher Chacha20?

Maybe this sounds like a stupid question. I'm sorry for that. I just wanted to know is it possible to encrypt a bitmap image file like *.BMP, and generate the ciphertext which is an obscure bitmap ...
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How can I decrypt AES-256 GCM with key with a IV that is missing?

I want to decrypt a file that has been encrypted using AES-256 in GCM mode in libressl. I have the key but I don't have the IV, is there any way I can still decrypt?
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Decrypt web https-transmitted file manually [closed]

When the communication between server and client starts -after a request, the computers agree on an encryption protocol to protect the data, the TLS handshake. The data may not be encrypted on the ...
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How do I preform the inverse key expansion of aes decryption? [duplicate]

I’m working on an aes encryption and decryption project in 8086 assembly! I managed to code an encryption algorithm and it worked perfectly. No I’m working on the decryption algorithm. I’ve managed to ...
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How to decrypt raw TLS bytes?

Is there any tool / way to decrypt raw bytes of a TLS 1.2 session, when the master key is known, even if forward secrecy is used? The closest I found is this. I know its possible using Wireshark, but ...
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Are there any cryptographic algorithms, which lets the user apply some modifications on the encoded data, without decoding it?

I would like to encode some data with a key, and send it to a third party. They don't know the key to decode it, but I would like to make it possible for them to apply some modifications on it. Then ...
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Can we sign and encrypt with RSA keys of both sender and receiver?

By using RSA encryption, it is possible to "encrypt" sign with sender's private key and then with receiver's public key, and decrypt with receiver's private key and then with sender's public ...