3k views

### Suppose I capture encrypted data that I want to decrypt. Could I use a server farm to decrypt?

For argument's sake, let's say that I'm a bad actor who produces malware. I've infected around 10,000 computers and smartphones with my malware, which runs in the background and can be used to make ...
32 views

### Vulnerability of low value generated key

I have read here that Elgamal is resistant to brute-force attack, because the group to where the key is selected is very large. But since the key generation is random, (i assume)there is a chance that ...
86 views

### Maximum security strength in bits of ISAAC cipher?

Wikipedia claims key length can be very big in this cipher, so I assume it can offer a million bits of security provided entropy of key is the same? Of course I can SHA-256 hash the key to allow any ...
200 views

### Encryption using matrix transformations

I have been thinking lately about a block cipher which takes a block of bits and arranges them in a square matrix. Then defining transforms on submatrices of the square matrix to scramble the bits. ...
72 views

### Does a thermodynamic limit on key search apply to quantum computers?

There is (or at least was) a thermodynamic reasoning that any form of brute force key search would require an energy at least $k\,T$ per key tested, where $k$ is Boltzman's constant and $T$ the device'...
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### Is this test result sufficient to steer clear from this RNG for cryptographic applications?

I'm not really interested in this PRNG. I'm more interested in understanding what it takes to fail the security threshold for cryptographic applications. I'm taking the C PRNG as an example. ...
11k views

### Differences between industrial and military cryptography

Industrial and military cryptography should follow the same basic rules, but what does make them different is: Higher key length, protocols unknown to the civilian world, and perhaps unique methods ...
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### Calculate all possible keys for AES 128 encryption to exploit hardware encryption

Some background: I am using the MicroChip ATAES132a for hardware encryption/decryption. The ATAES132a is very configurable and can be misconfigured in such a way that the encryption/decryption will be ...
3k views

### Is the cipher “Kalyna” with a 512-bit key length more secure AES with a 256-bit key?

Recently I have found out that Ukraine has its own symmetric encryption algorithm "Kalyna". Developers of this algorithm said that their algorithm is more secure than AES because of longer key length ...
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2k views

### How likely is a AES KDF bypass?

So I was wondering about some alternative attack scenario which I thought of when I started to understand KDF's . So lets say you have a cipher like AES and a strong KDF . And the legit user uses a ...
796 views

### Why can't we give block ciphers larger keys?

I have limited math's knowledge so sorry if this question sounds stupid. I saw many people complaining about AES, Twofish and Serpent that these ciphers all could be crackable in the near future and ...
368 views

### SHA256 - Which is less impossible?

To generate every possible hash would be ... impractical. To work backwards from any given hash is also incredibly labor intensive. Of the two, which is less impossible? Why?
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### How long would it take to brute force an AES-128 key?

How long would it take to crack a AES-128 key using the most advanced technology currently available? The hardware can be anything, be it a high-performance CPU, GPU or even FPGA?
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### Is there a way of increasing the time to brute force a cipher, but by increasing the ciphertext size instead of the key size?

If you have a symmetric-key algorithm that is limited to using a small key size (say 40-bits) is there any way you could increase the resistance to brute force attacks without increasing the key size? ...
72 views

### Indeterminate Message Validity as a Noise Source in High Volume Channels

Question Rephrased: Does randomisation of valid and invalid messages in a high volume channel add security? Scheme: valid messages are identified by a pre-shared random number sequence and noise- ...
65 views

### Key generation algorithm based on bytes in a drive [closed]

I am a novice cyber security student and thought of a way to generate a random cryptographic key. The algorithm works as follows: Get the size (in bytes) of every file in a directory (drills down ...
949 views

### Breaking Ransomware encryption

Recent news reports show that the UK's NHS (Nation Health Service) has suffered a major ransomware attack which is also affecting other parts of the world especially Spain and Russia, the effect is to ...
1k views

### Choice between AES-128 and AES-256 for password protection in MS Office

Why are we still using the default of AES-128 when password protecting a Microsoft Word document. My answer is and always has been - because its good enough and MS don't recommend changing to AES-256. ...
355 views

### can a weak cipher in a cascade weaken the result?

So i am a real beginner . And I use AES(TWOFISH(Serpent))) for my veracrypt file . So I asked myselfe a Question : When a Cascade is made the Key is split in parts for each algorythm . So if We ...
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### Recovering key in AES - Infinitely many known plaintext ciphertext pairs

Is it possible to recover key/algorithm in AES encryption more efficiently than via brute force given attacker has access to arbitrarily many plaintext ciphertext pairs. If so, are there other known ...
3k views

### How is the quality of a password calculated and what does it mean?

While using Keepass and using it to generate random passwords, I always have noticed the "quality" section but truthfully have never known what it actually means. So my questions are; How much ...
23k views

### Is password-based AES encryption secure at all?

For a few years I have put all my passwords in a text file and encrypted that file with a password using a software solution (Axcrypt) which uses AES-128. The password is not really strong, but I ...