Linked Questions

1 vote
2 answers
3k views

How weak is using AES with a 128 bit key but 64 bits of the secret key are public constants?

Respected community, I was wondering how weak would AES-128 be, if we provide only a 64 bit key with the other remaining 64 bits either zero bits or public constants, known to the attacker. Is it easy ...
Aravind A's user avatar
  • 1,020
0 votes
1 answer
71 views

Can we have an asymmetric key in AES? Clarification about PBKDF2 and AES-GCM in WebCrypto

Can we have an asymmetric key in AES? Clarification about PBKDF2 and AES-GCM in WebCrypto According to wikipedia AES page, AES is a symmetric-key algorithm. The algorithm described by AES is a ...
borracciaBlu's user avatar
1 vote
1 answer
403 views

KEY using AES-128, If P is less than 128 bits, padded with 0 and create 128 bits, any problem if average pw length is 6

For communication between the client and the website, use password (P) as the key using AES-128. If P is less than 128 bits, it is padded with 0 to create a 128 bits key. is there any problem with ...
lmmd1234's user avatar
78 votes
1 answer
47k views

How easy is it in 2022 to find a SHA1 collision?

Most of the answers I can find date to years back where the first collision(s) were found, but hardware mainly GPUs have progressed a lot in the past few years (with for example the new line of 3090s ...
Hormoz's user avatar
  • 789
1 vote
1 answer
726 views

Which passphrase length is good so it's hard to break bitcoin's PBKDF2 key?

According to https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki#From_mnemonic_to_seed To create a binary seed from the mnemonic, we use the PBKDF2 function with a mnemonic sentence (in ...
Guerlando OCs's user avatar
4 votes
5 answers
4k views

Why is a too fast hash function not secure?

I understand why we need hash functions to be fast enough for processing but slow enough for security. But I do not get why a very fast hash function can cause a collision. My guess is that a very ...
Seif Ashraf's user avatar
0 votes
0 answers
100 views

Finding the cleartext password given its MD5

Given powerful GPU and PC hardware, is it realistic to recover a password in a few hours given a cleartext's MD5? Max chars are 95, and the maximum length of the password is 15 characters.
prtqwsq's user avatar
8 votes
2 answers
2k views

SHA-512 - How difficult is it to find a hash digest beginning with at least twelve zeros?

I know it's possible to find a hash value with multiple zeroes in it, I know of some BitCoin hashes with it, but how difficult is it to find/create a hash digest with 12 or more leading hex zeroes in ...
sha512guest's user avatar
2 votes
2 answers
898 views

80-bit vs 128-bit security in today's world

In today's world of applications, I see a lot of the time a 256-bit encryption key is used, but what about an 80 or 128? What makes 256 the one to use. Is a 80 or 128 easily decrypted? Are comp ...
newJavaCoder's user avatar
0 votes
1 answer
196 views

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 ...
anon's user avatar
  • 1
1 vote
4 answers
1k views

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 ...
Interested Spectator's user avatar
2 votes
5 answers
2k views

Is it theoretically possible to create an unbreakable cipher?

I know this question might sound strange, but is it theoretically possible to create an unbreakable cipher if we don't consider bruteforce? Some of us believe that it is possible to create ciphers and ...
Evan Su's user avatar
  • 449
4 votes
1 answer
2k views

Is Mega.nz encryption vulnerable to brute force cracking by quantum computers?

I am interested in Mega.nz cloud storage. It is using end-to-end encryption. It says that it uses AES-128 to encrypt files And there are more details in their white paper But I saw that quantum ...
le menhir's user avatar
1 vote
2 answers
1k views

Recovery Passphrase Collission for BIP-39 and BIP-44

Referring to the standards of [BIP-39] and [BIP-44]: a 'master password' consisting of 12 words uniformly selected from a 2048-word dictionary corresponds to 128 bits of entropy, that is then used as ...
Daniel B's user avatar
  • 347
2 votes
3 answers
1k views

3DES security when K1=K3

I am mainly looking for security on 2-key $\operatorname{3DES}$ implementation where $K_1=K_3$. How hard or easy is it to crack $\operatorname{3DES}$ when $K_1=K_3$?
SSA's user avatar
  • 640

15 30 50 per page