Linked Questions

CTR mode does not use the decryption function at all, only the encryption function. This may suggest that a different primitive that has this "one-way" property could do the trick. For instance, I ...

First of all, I know it's a very bad idea to invent your own encryption algorithm. It's better to use existing known, trusted, extensively tested and studied algorithms with a proven track record. The ...

First of all, I know it's a very bad idea to invent your own encryption algorithm. It's better to use existing known, trusted, extensively tested and studied algorithms with a proven track record. The ...

Hashing is useful for checking that an input matches expectations without giving away the stored expected version - so confirming passwords etc. But are there other use cases? In general, ...

Suppose you'd use the following algorithm to encrypt a message Let $k$ be the key to encrypt with Let $m$ be the message to encrypt Split $m$ into groups of 512 bytes Given a hash function with a ...

On paper, it sounds *very* good to me: secure fast (in my tests it's somewhat slower than ECB (but without most of the weaknesses, more on that below) but faster than every other alternative I tested,...

I was wondering if the mere existence of a (by some definition) secure cryptographic hash function immediately implies an equally secure symmetric encryption scheme. By my understanding, one could to ...

Say I have an embedded device which is only capable of doing HMAC-SHA1 transformations (that device is, in fact, a YubiKey). Would it be secure to feed it like a block cipher in counter mode to get a ...

hashing some data and encrypting data share some similar attributes. Surely this is why "Difference between encrypting something and hashing something" has been asked. The point of this ...

We know that it's possible to create a hash using a stream cipher (for instance, RC4 or AES in Counter Mode). As stated here: "A Pseudo Random Generator (PRG) and a hash function are both Pseudo ...

Using MD5 or SHA1 for instance, and applying integers (as seed so to speak) to the hash function, in sequence, and only keeping, say, the first 64 bits of the resulting hash, do we always have a ...

I'm reading the salsa20 spec (sorry for the newbie question, i'm really a newbie here). Every paragraph ends with : "this operation is invertible", I suppose the whole salsa20 algorithm is. If I use ...

Can I use a keyed hash of a counter as a secure CSPRNG? E.g. 4th random block is Hash(4, seed) If not, what are the possible attacks?

I'm doing some exercises and of course I have read about the weaknesses of Vigenère cipher because it repeats the key. But what if I use a different hash every time? The hash of the "key + an ...

I hope you can help me understand the issue. I know creating my own encryption is not a thing which you should do, but I did this simple "encryption" a long time ago and discussed it with my teacher. ...