Questions tagged [brute-force-attack]

A brute-force attack is attempting to find a secret value by trying all possible values until the correct one is found.

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What is the general equation for determining the viability of a brute force attack on BIP-39? (Only performing access with pre-image - 12 seed words)

I'd like to be able to better define the security of a BIP-39 algorithm where I just consider the process of giving me a "seed phrase". Imagining a scenario where a hacker would try to gain ...
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Enumerating values from a linear congruential generator java Random()

During my research on a java application, I discovered that the nextInt(64) function of the java.Random() class is used to ...
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Are brute-force attacks made more difficult by removing the LUKS header?

If the LUKS header is removed from the LUKS partition, will this make the brute-force attack much more difficult? Can software tell which type of partition is it?
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64 bit key size Diffie Hellman

I am building a cryptographic El Gamal implementation on the Cardano Blockchain for a poker game. Each hand the players generate a DH 64 bit keys and shuffle the cards together via homomorphic ...
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Using MS Azure to crack password

I heard there is a possibility to perform a brute force attack of an password, I know there is an option to use graphic cards on AWS, but is there a solution for Azure too? Which costs would it take ...
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Protection (nonce addition?) against key discovery in AES 256

I've got a situation where I need to send message ciphered with AES-256. However the content, and therefore length, of the message may be intercepted before (don't ask;)) and the question I was asked ...
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How could I find the correct key pair given the plaintext and ciphertext

If I have a known plaintext and ciphertext pairs and 2 unknown keys of length 24 bits. (Assume encryption method is unknown) ...
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Is it possible to brute-force the nonce used in ECDSA?

It is a well-known fact that knowing the nonce used in signing the ECDSA signature allows the private key to be computed easily from that signature. If I understand it correctly, this nonce is a ...
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Is there a benefit to "double encryption" when it comes to attacks analyzing attempted decryption results?

This is a beginner's question related to general security, but it fits cryptography exchange because it's more specific to the action of cryptographic attacks and how they work. Assume the following ...
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Statistical Cryptanalysis. Would one "reverse" weak key schedule algorithms or peel off each one of internal rounds?

The context is iterated ciphers. Regarding Differential and Linear Cryptanalysis, the methods seem to make a cryptanalyst able to do an educated guess on a partial subkey (e.g. bits from the last ...
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How secure is it to share "Passwords" using Shamir Secret Sharing given a way to verify if password is correct?

Lets say you have a order $n$ finite field which you are using to create $k$ shares for a password using Shamir Secret Sharing. Assume that the attacker gets $k-1$ shares. Is it possible that the ...
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Algorithms for reducing the scope of a brute force attack on a cryptosystem? [duplicate]

I understand that during a brute force attack on a cryptosystem, an attacker is left with many, many, junk files, some which are partially readable (depending on the crypto algorithm used), and 1 ...
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Cracking secret key, n, and m by hand with the Diffie-Hellman key exchange brute force

Problem: You see Michael and Nikita agree on a secret key using the Diffie-Hellman key exchange. Michael and Nikita choose $p = 97$ and $g = 5$. Nikita chooses a random number n and tells Michael that ...
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What are those RSA Challenges, DES Challenges and RSA Factoring Challenges

Can someone explain the differences between the DES challenge, the RSA challenges, and the RSA factoring challenge? What were the aims? I think the factoring challenge was to encourage research, the ...
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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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To what degree does a high PKBDF-HMAC-SHA1 iteration count compensate for a weak passphrase entropy?

Lost a LUKS-encrypted laptop at the end of 2019 and now trying to figure out the odds of a very sophisticated attacker being able to break in. The LUKS container was created mid-2017 with LUKS1 ...
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Don't human generated passwords used with key derivation functions reduce the security of symmetric encryption?

The key size for AES is chosen as 256 because that's considered the minimum keysize which can protect against a brute force attack - i.e. $2^{256}$ tries. However, in practice, for a lot of ...
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Is it possible to crack cryptographic method with known input/output?

I've played around with John The Ripper before and it was able to successfully crack some personal passwords via brute force. However, in those scenarios the "unknown variable" was a ...
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Does keeping the IV secret in OFB mode makes brute-force more complex?

If we keep the IV secret, does that increase the complexity of finding the correct key? My first thought is that it increases complexity, but in real world, I can see that IV's aren't kept secret. We ...
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Matching accounts across multiple data leaks via their hashed passwords

I've heard about several instances where OSINT researchers were able to match user accounts from multiple data leaks purely based on their hashed passwords, assuming accounts had the same password on ...
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Difficulty of computing RSA keypair with given bits preset

Given a 2048-bit RSA public key physically burned into hardware, is it feasible to find a keypair where the public key could be "overlaid"? To detail, each bit in the hardware key is write-...
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Time Complexity of Exhaustive Search Algorithm

I have the sets $S_1=\{2,10,20,6\}$ and $S_2=\{25,26,20\}$ and I want to find which numbers sum to make 32. This is very easy by inspection; 6 and 26. It seems similar to the Knapsack problem, but I ...
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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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Proof of theoritical security of Shamir's secret sharing

community ! I'm looking for the proof of theoritical security of Shamir's secret sharing. I found some articles saying that it's assimilable to the halting problem, which implies that there is no ...
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Time complexity of a brute force attack on Shamir's Secret Sharing SSS

I have searched everywhere in academic papers about time complexity of a brute force attack on a Shamir's Secret Sharing key. I'm confused between if it is $O(p^k)$ or $O(p)$, such that $p$ is the ...
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How to calculate how long it will take to break deliberately weakened AES encryption?

for a project I'm looking to make as an art project a series of encrypted "time capsules" that have deliberately weak encryption, enough that it isn't feasible to crack them now, but could ...
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How to estimate time / difficulty to brute force scrypt (or similar) hash at various short fixed lengh outputs?

My particular use case is a hash function that: Is slow / computationally expensive. It would take a pretty long time, or be infeasible to guess the input, if the hash output and the algorithm are ...
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how can identify which cryptanalysis is used ( Indistinguishability cryptanalysis against classical ciphers) [duplicate]

I have 10 ciphertexts and 10 plain texts I want to know which cipher is from which plain text how can I know this I know the name of substitution cipher, transposition cipher, Vigen`ere cipher and ...
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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 ...
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How efficiently can an attacker forge parts of a fingerprint?

If two devices do not trust each other yet, you can't simply send the correct fingerprint across: you have to manually verify it. I am looking into the security of comparing only random parts of a ...
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How to express difficulty of breaking crypto when writing?

When writing for both technical and non-technical readers I find my self naturally wanting to write things such as : "..therefore it would be impossible to decrypt the data." When trying ...
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How Secure Is Splitting A Bitcoin Private Key?

NOTE: This question cannot be posted to Bitcoin SE because it will not render there due to the mathematical notation. Since the mathematical notation is part of the question, this is the more ...
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How many NVidia 3090 would you need to brute force a 1024 key in one day? [closed]

How many NVidia 3090 would you need to brute force a 1024 key in one day?
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Brute force strategy

I am a beginner in this field, and I was thinking about brute force strategies to break symmetric key encryption. Let's say we have a block cipher in CTR mode and the key is 56 bits in size. What ...
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Reversing black box algorithm

I'm trying to solve the next problem: We have X - input vector, its length is 128 bits. Output vector Y, its length 2048 bits. ...
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How secure is file-based encryption in Android?

I want to estimate the cost of breaking file-based encryption in Android given a password entropy. The only information I found so far is this: The stretched credential is the user credential after ...
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Will an algorithm that constantly changes the order of 10 hash functions be protected from an ASIC?

Let's imagine one hash function that is based on 10 hash functions. For every input, it changes the order of the 10 hash functions. So, for example: ...
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How long would it take all of the supercomputers or cloud computing on Earth to bruteforce a significantly long password?

I was arguing with a colleague who thinks that SHA256 (password + 64 character static salt) is "insecure." My argument is that nothing in cryptography is "secure," it's all a ...
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Encrypting multiple groups of data with separate keys in a single encrypted column

I will write this question using a database example, but please note this detail may be irrelevant. Let's say I have data belonging to N clients stored in a single column of a database table. Each ...
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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 ...
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How much brute forcing efforts needed to find 2 or more inputs that generating same SHA256 outputs

Say I have SHA256 hash result that produced from 2000 bits inputs. For example, 0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef (64 bit hex representation) is the SHA256 output. ...
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$\mathrm{Hash}(A\|B)$ where $B$ is known, $A$ is unknown. Would knowing $\mathrm{Hash}(A\|C)$ as well as $C$, speed up a brute force search for $A$

Let's say $\mathrm{Hash}(A\|B)$ is a hash of two concatenated strings, $A$ and $B$. Suppose I am trying to figure out $A$ from $\mathrm{Hash}(A\|B)$, I know $B$ but not $A$, I want to brute force to ...
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3 votes
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Probability of false positive key matching two plaintext/ciphertext pairs

Given a keyspace of $ 2^{80} $ and plaintext space of $2^{64}$. And two plaintext and ciphertext pairs $(x_1, y_1)$ , $(x_2, y_2)$. Now we have $2^{80}/2^{64} = 2^{16}$ keys that encrypt $x_1$ to $y_1$...
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Brute force attack on a block cipher with length n [duplicate]

Consider a block cipher whose block length is 𝑛. 𝑁 = 2𝑛 is number of possibilities. Imagine we have 𝑡 plain text-cipher text pairs { 𝑃𝑖, 𝐶𝑖 = 𝐸𝐾(𝑃𝑖) } , where the key 𝐾 selects one of ...
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Differential and Linear Cryptanalysis on Random Sbox

Assume that we use the key to perform a uniform permutation to generate a sbox. The literature is rich supporting the statement that a random Sbox can make any cryptographic scheme weaker. I have ...
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What is the longest AES key that has been recovered in practice?

I can recover something trivial like a 16-bit AES key in practice. I'm confident that a 64-bit AES key can be recovered. However, I have been unable to find any documentation of the biggest AES key ...
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Periodic re-keying during full drive encryption

A man encrypted a hard drive in 1996 using three key 3-DES with a 64 bit IV and CBC mode in the following manner using known 1990s algorithms on a 1996 PC. Here is how he did it. Start with a ...
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How long brute force AES-128 at 24 bits of key

I have 1 block of encrypted data with AES-128, but I know 104 bits of 128 bits the key. How long it will take to brute force 24 bits of a key at Intel I 7 CPU? How can I calculate that?
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2 votes
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Using Optimal Prime Field in ECC

"Optimal Prime Field is a family of 'low-weight' prime fields that allow for efficient software implementation of all operations requiring a modular reduction, in particular the field-...
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2 votes
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PBKDF2-HMAC Collisions

Trying to understand the well known property of these collisions when used with SHA1, SHA256, etc. where a given key is larger than the block size of the digest function. In these cases the smaller of ...
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