Newest 'known-plaintext-attack' Questions

3

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1answer

66 views

Number of plaintext–ciphertext pairs needed to rule out false keys with a reasonable likelihood in AES

I am new to cryptography and I've got the following question from Understanding Cryptography: Imagine that aliens — rather than abducting earthlings and performing strange experiments on them — drop a ...

asked Apr 4 at 20:31

userabc123abc123

311 bronze badge

0

votes

0answers

36 views

CPA attack against Symbol obusfcation

We have a transmission system such that a message $m\in[0,1]$ is converted to $N$ symbols $S=[s_1,s_2...s_N]$ and $s_i\in[1,2,3,4]$. The obfuscation of the symbols is as follows: A key $K1$ seeded to ...

cryptanalysis chosen-plaintext-attack known-plaintext-attack

asked Mar 15 at 1:09

Riva11

355 bronze badges

1

vote

2answers

85 views

Known Plaintext attacks using standard greetings etc

In all modern ciphers, even if one bit of input changes, then half of the output will change because of diffusion. Considering this, how exactly will knowing standard salutations, etc. ("Hello ...

cryptanalysis known-plaintext-attack

asked Jan 6 at 2:27

user93353

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0

votes

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63 views

Known Plain Text Attack DES-OFB on Crack.sh

I am trying to do a known plaintext attack on DES-OFB through crack.sh. I have been having trouble lately. I keep getting blank text file back with no keys returned. Does anybody know if DES-OFB is ...

encryption des brute-force-attack known-plaintext-attack ofb

asked Dec 18 '20 at 4:25

bambi

11 bronze badge

0

votes

0answers

59 views

Known plaintext attack on AES with CBC

Assume I have a plaintext and a ciphertext, encrypted using some key and AES with CBC mode. I don't have a service, that I can send something to, so I can't use the Padding Oracle attack. Are there ...

aes cbc known-plaintext-attack

asked Dec 11 '20 at 15:53

Anegng

11 bronze badge

0

votes

0answers

28 views

How to falsify RSA signature with known message [duplicate]

I have a question about the RSA signature. Let's say Alice has $(d,n)$ as the private key and $(e,n)$ as the public key. In order to sign a message $m$, Alice computes $y = m^d \bmod n$ and sends $(m,...

rsa signature known-plaintext-attack

asked Dec 7 '20 at 17:52

John

11 bronze badge

2

votes

1answer

87 views

Combining CTR and ECB modes to prevent attacks

In Reusing AES-CTR Keys and IVs for File Encryption, the OP was asking about a composite encryption scheme $$C_i = E_K\left(P_i \oplus E_K\left(IV + i\right)\right)$$ which is basically just a CTR ...

encryption initialization-vector ctr known-plaintext-attack ecb

asked Nov 7 '20 at 8:44

ManRow

1475 bronze badges

0

votes

1answer

107 views

Consequences of AES-GCM always encrypting the same plaintext

I am analysing an authentication protocol. In this protocol AES-GCM is used to encrypt part of the messages. Regarding the authentication protocol, I made the following observations: The plaintext ...

aes authenticated-encryption known-plaintext-attack aes-gcm

asked Oct 6 '20 at 11:38

Kobodjo

311 bronze badge

0

votes

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106 views

How to perform a known plaintext attack?

I have got the following documents: (1) The plaintext (2) The ciphertext (3) The python program used to encrypt/decrypt the text My goal is to find the key that was used to encrypt the plaintext into ...

encryption known-plaintext-attack decryption

asked Oct 3 '20 at 1:37

Holly Iveburn

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3

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1answer

96 views

How much information do I leak if I upload multiple ciphertexts with cleartext overlaps?

Suppose that $t_1, t_2, \ldots, t_n$ are my clear texts. Suppose that for any $(i,j) \in \{1,2,\ldots,n\}^2$, $t_i$ and $t_j$ only differ in, say, the 1st $m$-many characters. Finally, suppose that I ...

rsa aes cryptanalysis known-plaintext-attack scrypt

asked Aug 15 '20 at 7:04

caveman

2931 silver badge13 bronze badges

0

votes

1answer

114 views

Safety of encryption when knowing part of the content [duplicate]

I want to encrypt a JSON file while exposing its interface (the name of the object fields) in clear text. Since this exposes part of the content of the file, my guess is that an attacker could use ...

encryption known-plaintext-attack

asked Aug 9 '20 at 10:36

SystematicFrank

1031 bronze badge

2

votes

2answers

97 views

Construction of a “simple”, nothing-up-my-sleeves, provably KPA resistant symmetric cipher

Why is AES secure? Apparently there is no answer - Why is AES resistant to known-plaintext attacks?. With this in mind, one would obviously want a cipher that is mathematically provable to be ...

encryption aes known-plaintext-attack

asked Jul 14 '20 at 19:42

super

4533 silver badges9 bronze badges

0

votes

0answers

82 views

RNG to hide some bits

Suppose I have a sequence of bits of length M. I need to hide N out of M bits (hiding means forcing them to be 0) using RNG with a key. How I can relate the output of RNG to the number and positions ...

encryption keys random-number-generator known-plaintext-attack chosen-ciphertext-attack

asked Jun 24 '20 at 9:43

Riva11

355 bronze badges

0

votes

0answers

35 views

What kind of approach can I use to reverse the following encryption scheme?

I'm trying to reverse an encryption scheme without success. I have several pairs of ciphertext + plaintext and found the encryption method to be something like this: ...

cryptanalysis keys known-plaintext-attack

asked Jun 21 '20 at 2:50

Miguel Ángel

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15 views

Generating RSA keys with plain and ciphertext [duplicate]

I have plaintext and ciphertext. Is it possible to generate an RSA key pair that encrypts the plaintext to ciphertext and decrypts ciphertext to plaintext. I don't need to find the original key pair ...

rsa known-plaintext-attack

asked May 29 '20 at 6:09

Shashank

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0answers

39 views

Memory required for known plaintext attack on general block cipher

Consider a block cipher on binary strings of length $k$ and keys which can be any binary string of length $n$. With $k2^n+k$ memory we can store all key/ciphertext pairs for a fixed plaintext and this ...

block-cipher known-plaintext-attack

asked May 21 '20 at 17:08

zz7948

1858 bronze badges

0

votes

2answers

69 views

would this be classed as a cipher text attack?

Say i'm given a cipher text to decrypt, however i also have access to a server that performed the encryption; where i could enter any plaintext and observe the result of encryption. would it be ...

cryptanalysis chosen-plaintext-attack known-plaintext-attack ciphertext-only-attack

asked May 18 '20 at 21:00

hithere

11 bronze badge

8

votes

3answers

391 views

One round of AES-128

Maybe it’s a silly question, I’m interested in the best known/chosen plaintext attack on only one round of AES-128. More specifically, what is the smallest number of known/chosen plaintext/ciphertext ...

aes block-cipher chosen-plaintext-attack known-plaintext-attack

asked May 17 '20 at 9:30

zz7948

1858 bronze badges

2

votes

1answer

109 views

Is it possible to perform CPA(Correlation Power Analysis) when attacker has only specific round's waveform?

I read Quite a lot document about breaking AES using CPA. But most of them, assuming that attacker has the first or last round of the waveform(trace) and exploit SubBytes. My question is if the AES-...

aes known-plaintext-attack side-channel-attack hamming

asked May 9 '20 at 17:47

Lee Anon

235 bronze badges

1

vote

1answer

44 views

Is it safe to distribute different portions of the same data encrypted with different AES keys?

Assume I have a block of data consisting of three segments A, B and C. With "segments" I mean a particular section of a bit stream, so if the whole binary data was simply ...

aes known-plaintext-attack

asked Mar 10 '20 at 12:17

LWChris

1555 bronze badges

5

votes

2answers

329 views

Is the ChaCha20 block function reversible using known plaintext?

I've been recently implementing the chacha20 stream cipher with Poly1305. As the core operations which make up the Quarter Round of chacha20 (ARX - Addition Rotation Xor) are indeed reversible, does ...

algorithm-design stream-cipher known-plaintext-attack chacha

asked Feb 15 '20 at 9:17

Vivekanand V

8283 silver badges11 bronze badges

2

votes

1answer

419 views

How does one conduct a known-plaintext attack on an algorithm?

My question is two-fold: Say I am given a total black box and I have n number of plaintexts as inputs that map directly to $n$-number of ciphertexts as outputs. This is all I know, and I do not have ...

known-plaintext-attack

asked Feb 15 '20 at 3:24

the_endian

1656 bronze badges

3

votes

1answer

192 views

How to secure Elliptic Curve ElGamal encryption against known plaintext attacks?

If I have an encoding function $f(x)$ that maps a message $m$ to a point $P$ on a suitable Elliptic Curve $E$ . If I have the public key $Q$ of my recepient then I can encrypt the message as follows: ...

elliptic-curves elgamal-encryption known-plaintext-attack

asked Feb 9 '20 at 11:39

Vivekanand V

8283 silver badges11 bronze badges

0

votes

1answer

178 views

Recognizing and decrypting custom cipher with known plaintext and ciphertext

I've been trying to reconstruct an encryption algorithm that produces a known ciphertext from a know plaintext. I have done some analysis: the algorithm operates on single bytes a plain text can be ...

encryption stream-cipher known-plaintext-attack

asked Jan 5 '20 at 23:15

Pruzo

193 bronze badges

1

vote

0answers

39 views

Known plain-text attack on Kerberos

This is a form of the Kerberos protocol I have two questions. Why does this protocol give the opportunity of a known plain-text attack because of no authentication of Joe? And how would an attacker ...

kerberos known-plaintext-attack

asked Dec 14 '19 at 17:57

nmq

111 bronze badge

3

votes

0answers

226 views

Why are cyclic keys in Feistel Networks insecure?

So everyone seems to agree that recurring round keys in a Feistel network (eg. using the same key for every round) are a massive security leak. When researching this, the only thing I found is the ...

block-cipher known-plaintext-attack feistel-network

asked Nov 30 '19 at 16:00

Lukor

1652 silver badges7 bronze badges

1

vote

1answer

232 views

XChacha20poly1305 vulnerability to known plaintext attacks

During a security audit, the guy said our cryptosystem is vulnerable to known-plaintext attacks. He said that's because «the implementation uses a crypto_stream_xor() approach» (from libsodium). That'...

passwords known-plaintext-attack salsa20

asked Oct 30 '19 at 13:40

Chacha123

113 bronze badges

1

vote

1answer

93 views

Is it possible to narrow down the possible keys used for AES CBC encryption, knowing a given plaintext and its ciphertext, where IV=0? [duplicate]

I'm brute forcing a ciphertext with a given dictionary to figure out which key was used. However, it's been hinted at that there is a way to narrow down the dictionary to a smaller subset of ...

keys symmetric cbc brute-force-attack known-plaintext-attack

asked Oct 18 '19 at 23:50

Alex

111 bronze badge

2

votes

0answers

597 views

Known Plain-text Attack [closed]

How can I find the known plain text P2 based on the given information? Assuming that the encryption is made using a common initialization vector and the mode used for encryption is OFB. ...

known-plaintext-attack ofb decryption

asked Oct 11 '19 at 14:11

faizan

211 bronze badge

2

votes

0answers

101 views

Encrypted ZIP and plain text attack [duplicate]

I have a Zip archive containing a single password-protected file file.txt. The encryption is "ZIP 2.0 Default Encryption" (ZipCrypto). I know what kind of text (...

known-plaintext-attack password-based-encryption

asked Oct 6 '19 at 17:34

leg020

212 bronze badges

3

votes

1answer

159 views

Why is the Domingo-Ferrer cryptosystem not used in practice?

The Domingo-Ferrer cryptosystem is a fully homomorphic cryptosystem. It works fast enough. I have only seen known-plaintext attacks. Is this a reason not to use it in practice? Or are there more ...

homomorphic-encryption attack known-plaintext-attack

asked Sep 22 '19 at 17:49

hey

332 bronze badges

2

votes

0answers

59 views

Known-plaintext attack against E0 with 2745 bits per frame instead of 24

In the paper The Conditional Correlation Attack: A Practical Attack on Bluetooth Encryption, an attack against the E0 cipher is described which can break it efficiently in a known-plaintext attack: ...

known-plaintext-attack lfsr e0

asked Aug 25 '19 at 7:42

forest

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1

vote

1answer

85 views

Cipher recommendation for known-plaintext attack

I need to encrypt a 4-digit number. The cipher-text can be up to 11 digits long and there are no limits for the key size. Considering that the attacker has access to both the cipher-text and the ...

known-plaintext-attack

asked Aug 15 '19 at 14:51

Miguel

132 bronze badges

2

votes

1answer

244 views

How many required known plaintexts for an attack are considered insecure?

I stumbled over this problem when looking at symmetrical block ciphers with a relatively small block size like 32 bit. When I was looking at more common block ciphers with a 64 bit, I learned that ...

block-cipher known-plaintext-attack chosen-ciphertext-attack blocksize

asked Jul 21 '19 at 17:57

jonhue

1234 bronze badges

2

votes

1answer

570 views

Hill cipher: How to find an unknown key of unknown size

How would you tackle the problem of finding the key (you don't know the length) to a Hill cipher when knowing only one 12-letter word of plaintext and its corresponding ciphertext? CONVERSATION has ...

known-plaintext-attack hill-cipher

asked Jun 19 '19 at 10:59

Christo Todorov

211 bronze badge

0

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0answers

58 views

Unique numbers with $P^aQ^bR^c \mod N$ for each combination of $a,b,c$ possible? Would it be safer than separate form (like $T^a \mod P$ for each)?

Main question: Is the computation of $a,b,c$ in $P^aQ^bR^c \mod N$ (much) harder than in $T_p^a \mod P$, $T_q^b \mod Q$, $T_r^c \mod R$ ? (assuming the first form exists) $P^aQ^bR^c \mod N$ With $P^...

cryptanalysis algorithm-design attack known-plaintext-attack

asked Apr 20 '19 at 10:09

J. Doe

5892 silver badges12 bronze badges

0

votes

1answer

47 views

How much more secure is $c = mg_1^r + g_2(g_1(g_1^r-1)/(g_1-1)) \mod p$ compared to just $c = mg_1^r \mod p$ (dis. log), all known but $r$?

To encode a message $m$ to a cipher $c$ you can use the only hard solvable problem of computing the discrete logarithm with a generator $g$ in base over a prime $p$. $c = mg_1^r$ mod p If an ...

cryptanalysis algorithm-design elgamal-encryption attack known-plaintext-attack

asked Apr 19 '19 at 19:09

J. Doe

5892 silver badges12 bronze badges

1

vote

1answer

204 views

IV Re-use and Chosen Plaintext against 56bit Blowfish (CBC)

I am looking at a very old protocol which uses Blowfish to encrypt packets with a constant 8-byte IV in CBC mode. Assuming I have: The ability to arbitrary encrypt known plaintexts The IV I know ...

cbc initialization-vector known-plaintext-attack key-reuse blowfish

asked Mar 27 '19 at 13:58

pavja2

1112 bronze badges

0

votes

1answer

417 views

how to compute IV with AES CTR if key, plaintext and ciphertext are known?

Given $E_k$, which a block-cipher using the (known) key $k$, and a plaintext-ciphertext pair $(p,c)$ where $c$ is the encryption of $p$ using CTR mode, can the initialization vector be recovered using ...

aes initialization-vector ctr known-plaintext-attack

asked Feb 23 '19 at 13:56

lclevy

32 bronze badges

0

votes

0answers

42 views

Is it necessary to study the KPA security for asymmetric encryption algorithms in addition to CPA security? [duplicate]

In a KPA attack model, an adversary $\mathcal{A}$ has access to pairs of messages $(m_i,c_i)$ which are encrypted using some asymmetric algorithm. However, assuming either El-Gamal or RSA algorithms, ...

public-key chosen-plaintext-attack known-plaintext-attack

asked Feb 6 '19 at 7:15

Ali Shakiba

1134 bronze badges

1

vote

0answers

373 views

show that G' is not a secure PRG even if G is

Hello I'm trying to show that the function G'(s) = G(s) || G(G(s)) is not a secure PRG even if G is. My first question is that in this case, how do I know what G ...

pseudo-random-generator attack known-plaintext-attack

asked Feb 4 '19 at 0:37

Martin

1111 bronze badge

2

votes

1answer

1k views

AES-CBC ciphertext manipulation with known IV and plaintext! [duplicate]

I'm currently practicing on a purposely flawed login page, where I have to change the value of a cookie to enter. The cookie is an encrypted and encoded form of a simple JSON string with fields "admin"...

aes known-plaintext-attack

asked Jan 25 '19 at 4:28

sp4rr0w

233 bronze badges

2

votes

0answers

90 views

Is my deniable encryption scheme reasonable?

I was experimenting with RubberhoseFS, but since it is very hard to compile on anything modern, I decided to implement my own version, stripped of many unnecessary features. Namely, my implementation ...

key-derivation known-plaintext-attack deniable-encryption

asked Jan 11 '19 at 11:17

programagor

1213 bronze badges

7

votes

3answers

8k views

Is it possible to find the key for AES ECB if I have a list of plaintext and corresponding ciphertext?

Assume I have a list of plaintext text and its corresponding ciphertext which was created using a specific key with AES in ECB mode. Can I recover that key? If, how big does the list of plaintext ...

aes attack known-plaintext-attack ecb

asked Nov 11 '18 at 18:30

Richard Jones

1811 silver badge3 bronze badges

6

votes

1answer

203 views

On CPA & KPA security of $\boxplus$-Feistel

I am interested to identify the effect of replacing $\oplus$ with $\boxplus$ on basic balanced Feistel structures over $r$-rounds. Given: $F_\boxplus[L,R]= [S,T] = [R,L \boxplus f(R)]$ where $f$ is a ...

pseudo-random-function chosen-plaintext-attack known-plaintext-attack feistel-network

asked Nov 2 '18 at 10:20

hardyrama

1,9201 gold badge10 silver badges34 bronze badges

1

vote

1answer

1k views

Known Plaintext Attack for Modified OFB Mode of Operation

Question: Assume a variant of the OFB mode by which we only feedback the 8 most significant bits of the cipher output. We use AES and fill the remaining 120 input bits to the cipher with 0's: Why is ...

block-cipher modes-of-operation known-plaintext-attack

asked Oct 26 '18 at 15:31

esra

6496 silver badges15 bronze badges

4

votes

1answer

2k views

Known Plaintext Attack on Block Cipher in ECB and CBC Modes of Operations

These 2 similar questions are from Paar's Understanding Cryptography. I could not see the answer so if someone can help I will appreciate: Question1: We consider known plaintext attacks on block ...

block-cipher modes-of-operation known-plaintext-attack

asked Oct 25 '18 at 20:25

esra

6496 silver badges15 bronze badges

1

vote

1answer

183 views

Ethereum RLPx protocol for inter-node communication - flaws in the encryption

Ethereum uses RLPx/devp2p for inter-node communication. The protocol is encrypted using Elliptic Curve Integrated Encryption Scheme (see ref) Under Known-Issues I found this paragraph: The RLPx ...

encryption ctr known-plaintext-attack cryptocurrency ecies

asked Oct 11 '18 at 21:05

ivicaa

1135 bronze badges

1

vote

1answer

147 views

It's safe to store a known value (for checking) next to the actually encrypted values

The high level details of the encryption I'm using is: AndroidKeyStore create/store RSA key AES key is created and wrapped with RSA/ECB/PKCS1Padding Encrypted AES is saved to disk. Data is encrypted ...

known-plaintext-attack aes-gcm

asked Aug 1 '18 at 12:28

Budius

1334 bronze badges

2

votes

3answers

716 views

Known-plaintext attack on 1-round Feistel networks

Consider a simple, 1-round Feistel network. Because the ciphertext is essentially $(L_1,R_1)$, if one knows the plaintext $(L_0,R_0)$, the only unknown left is $K$. However round functions in ...

known-plaintext-attack feistel-network

asked Jun 21 '18 at 14:27

DBor

212 bronze badges

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