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### 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 ...
28k 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 ...
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 ...
10k 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 ...
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 <...
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 ...
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?
847 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 ...
795 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,...
1k views

### AES128 and 256 Microsoft Office

I realise this is kind of a basic question but its one I must have an answer too. One of the questions I have had thrown at me recently is why are we still using the default of AES128 when password ...
895 views

### How much processing power should you assume an attacker has?

The answer to this question says that you should assume an attacker can do one billion operations per second: Key Size for Symmetric Homomorphic Encryption Over the Integers Is that a single attacker ...
910 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 ...
532 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 ...