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### Can we bound adversarial power in terms of total entropy in universe? [duplicate]

The strengths of various cryptographic primitives are often explained (though not defined) in terms of how long it would take to break under the current best known attacks. For example, apparently the ...
12k 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 ...
38k views

### Why is AES resistant to known-plaintext attacks?

At least it's my understanding that AES isn't affected by known-plaintext. Is it immune to such an attack, or just resistant? Does this vary for chosen-plaintext?
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Dropbox have recently published How Dropbox securely stores your passwords Is this really more secure than using bcrypt with a complexity of 11 or 12 ? The password "chain" is secure as its weakest ...
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### 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 ...
21k views

### Does SHA-1024 hash exist?

Does SHA-1024 cryptographic hash function exist similarly to SHA-512? If not, what's the reason for that? Links: SHA-2 at Wikipedia SHA-3 at Wikipedia
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### 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 ...
41k views

### 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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### 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 ...
2k views

### 1 Billion Bit Encryption?

So, browsing through YouTube, I stumbled on this video interview of John Draper (Captain Crunch), one of the first "hackers". He talks for about 3 minutes (until 27:48) about his home rolled ...
888 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 ...
56k views

### Twofish vs. Serpent vs. AES (or a combo)

I've seen some posts and info online, but they are from 2009, 2010, 2011 or 2012, which is 3-6 years ago, which is a very long time. So I'm looking for an up-to-date answer about which of these is the ...
4k views

### What is the most secure ECC Curve?

I have for a while used Koblitz curve (sect571k1), in ECDH and ECDSA. But I have started wonder if it is the most secure. I prefer security over efficiency. So the curve doesn't have to be the most ...
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 ...
803 views

### Is there a proof for showing any cryptogram is crackable?

I commonly hear statements along the lines of "all cryptograms are crackable - it's only a matter of time". Is there a proof to show that any cryptogram is "crackable"? The proof may be of a more ...
35k views

### Is SHA-256 safe and difficult to crack? [duplicate]

I am trying to crack a SHA-256 hash but I am not sure how to approach this in an efficient way. The following is known of the original non-hashed content: 64 characters long only consists 0-9 and a-z ...
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 ...
1k views

### 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. ...
12k views

### ECDSA with SHA256 and sepc192r1 curve: Impossible, or how to calculate $e$?

I need to use ECDSA as the signing algorithm and SHA256 for hashing the message. I'm running into troubles verifying the signature calculated on two different platform (one is BouncyCastle, another ...
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 ...
3k views

### ECC keys vulnerable to brute force attack?

I have started learning about Elliptic Curve Cryptography (ECC). Since the key size required in ECC is relatively smaller than the key size in RSA (to provide the same encryption strength), I wonder ...
7k views

### Algorithm for generating OAuth tokens

I'm trying to find a good algorithm for generating authorization codes, access tokens and refresh tokens in an API. Currently, I am looking into the following setup: Tokens are generated using the <...
2k views

### Why is AES unbreakable?

Why is it said that AES is unbreakable? Brute force attacks would take years to crack it, so is it possible to crack it if the computational speed of machines increase in the following decade?
1k views

### Diffie-Hellman key exchange - why is modulo operation necessary?

Could someone explain why it's necessary to have the modulo operation in the Diffie-Hellman key exchange? Let's imagine we do DH without the modulo operation ($A = g^a, B = g^b$). Would that not work,...
940 views

### Is there a truly safe signing algorithm?

After reading this question, I'm pretty shaken up. A determined attacker with \$100 in loose change can crack any RSA key in a couple of hours. After believing that these algorithms would take millions ...
911 views

### Can there be a need for 1024-bit (symmetric) encryption?

I think we are all aware of the CAESAR-competition. Now the aim of this competition is to select a (portfolio of) winner(s) which provide authenticated encryption. I'll now assume that the results ...
319 views

### Multi Factor Encryption?

I got an alert last night to the keywords above and was curious, so took a look at the tor site flagged which is the following one: http://nsrz5iogimqwgeax3clpp6hvfy6viom2woy7dghgxes4sqk63r7svoqd....
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### 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. ...