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 someone please explain RSA-OAEP in plain english mathematically?
RSA mathematics: https://youtu.be/4zahvcJ9glg
I understand how RSA works mathematically.
Can someone explain RSA-OAEP in plain english?
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What is difference between Payload -> Sign (JWE) -> Encrypt (JWE) vs Payload -> Encrypt (JWE)-> Sign (JWE)? [duplicate]
In RSA® Adaptive Authentication for eCommerce specification, the below flows are described.
Payload -> Sign (JWS) -> Encrypt (JWE) | Decrypt -> Verify -> Payload
Payload -> Encrypt (JWE)...
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How to encrypt with CBC, step by step?
I have this message "Hello from another world"
Can you explain how to encrypt it with CBC step by step?
Are the message characters ...
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Is finding an encryption (or hash) algorithm science, or is it art? [closed]
I'm not into cryptography, but I read a bit about it.
I wonder:
AFAIK all encryption (decryption) and hashing routines are built using some very primitive functions (let's name them "atoms" ...
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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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Is it possible to securely encrypt some text with password without a computer?
Encrypting text with a computer has problems: we need to worry about hardware backdoors in processors, motherboards, and extension cards, software backdoors in OS, vulnerabilities in software, and ...
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Which encryption algorithm should I use for encrypting a string [closed]
I have a very important string it's of around 20-40 words. I want to encrypt this string and store it online . Which encryption algorithm will be useful for me.
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Double Encryption Problem from Boneh/Shoup Textbook
I am working on the following problem from the Boneh/Shoup textbook:
5.1 (Double encryption). Let E = (E,D) be a cipher. Consider the cipher E2 = (E2, D2), where E2(k,m) = E(k, E(k,m)). One would ...
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Privacy preserving transformation between hashes
I think this question is related to this other question, but somewhat different.
Let there be a hidden datum $D$ that we observe using a hash function $H_1$, $h_1 = H_1(D)$. There's another hashed ...
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Cracking an XOR crypt with a know key length [closed]
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 be 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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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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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?
eric su
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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.