45 questions linked to/from How reassuring is 64-bit (in)security?
1 vote
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### 80-bit security and attack time

Many designer claimed that their cryptography scheme has 80-bit security. So how to calculate the time of attcking this 80-bit security cryptography scheme, such as 80-bit security RSA using a kind of ...
• 341
1 vote
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### MD5 hash: retrieve an element of a source string

Suppose you have a string, precisely an MD5 hash string, which basically it is computed in the following way: "element1:element2:element3" So, in order to get ...
• 21
1 vote
107 views

### Good pre-image resistance value for hash visualization

I want to do "hash visualization", i.e. derive a human-meaningful information from a hash, like a phrase or an avatar. But the current techniques usually don't use many bits, for example tripphrases ...
1 vote
306 views

### Supercomputer to crash hash

For NVIDIA TESLA V100 I know a hashcat performance for SHA1: it is about 17000 MH/s. Performance index for V100 is FP32 5120, FP64 2560. But what about supercomputers? For example Summit ...
• 197
1 vote
194 views

### Algorithm/encryption technique which outputs a set number of numerical digits e.g. 20 digits from a given input

What the name of the algorithm/encryption technique which outputs a set number of numerical digits e.g. 20 digits based on some input. You can input some data e.g. text or numbers but the output is ...
1 vote
304 views

### How to make my hash more robust to the brute force?

I'm using PBKDF2 SHA 256 with 100 000 iterations to generate a secret. I want to increase the cost of brute forcing the passphrase I use to generate the secret. I'm thinking of using scrypt after ...
1 vote
611 views

### Given partial key exposure and encryption oracle, can we recover full AES key?

Suppose I have an encryption oracle for AES with some key $k$ (16 bytes) and that I know $n$ bytes of it. Is it possible to recover the rest ($16 - n$) in complexity less than $256^{16-n}$?
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### 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 ...
• 101
230 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 ...
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### Calculating DES key knowing message before and after encryption [duplicate]

I've 8 bytes before encryption (for example: 01 02 03 04 05 06 07 08) and 8 bytes after DES encryption: ...
• 101
402 views

### Finding and matching SHA512 Unsalted Hash

We are given a list of possible strings, there are $32^{16}$ ($=2^{80}$) to be exact. We also have the unsalted SHA512 of the original target string. How long would it take to go through those ...
913 views

### Show that if a fixed key MAC is not collision resistant then the MAC function is not computation resistant for every key K

I'm really having some trouble with this one. Let $H$ be a MAC function. For every key $K$ we can create an unkeyed hash function (i.e.an MDC) by using $H$ to hash messages with the fixed key $K$. ...
1 vote
59 views

### Can Trivium ciphertext be decrypted by an adversary if the key is known, but the IV is not?

Suppose that the adversary is able to recover the key of Trivium cipher. But the associated IV is unknown to him. Will he be able to decrypt the ciphertexts without any complexity?
• 73
1 vote
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### How reassuring is 64-qubit security?

After we've concluded that 64-bit is an insecurity for classical computers, I think many would like to know, how secure in a perspective view, is 64 quantum bits security. As we know, the Grover's ...
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