Linked Questions

Generate a 256-bit random nonce. XOR it with a 256-bit reusable symmetric key. This is x. We represent numbers in simple binary instead of a counting function. <...

The weakness CWE-329 is an interesting problem with CBC mode. However, does this same weakness affect the other modes of operation that rely upon an IV such as: PCBC, CFB and OFB? My gut feeling is, ...

To perform a bit flipping attack, the previous block is modified by using XOR. This results in an altered plaintext. However, now the ciphertext of the previous block is altered, hence it will result ...

In cryptography, a block cipher mode of operation is an algorithm that uses a block cipher to provide information security such as confidentiality or authenticity. A block cipher by itself is only ...

I'm currently studying crypto and wondered what would be wrong with the following process... I want to encrypt a long message $M$ with a short symmetric key $K$ and a public nonce $X$. The idea is to ...

When using AES-GCM I know that I am supposed to use a new initialization vector every time I call the AES-GCM algorithm with the same key. What are other rules must be followed to use AES-GCM ...

What is the difference between; pseudorandom permutation pseudorandom function block cipher? Very confused with the 3 terms and I am not good at advanced math. Can someone explain in plain word?

I have a standard random key and IV. Then I am creating a cipher using these keys and iv and then encrypt a specific message. Later on, if I try to encrypt another message with the same cipher(which ...

In the counter mode of encryption, the nonce cannot be used again unless a new block cipher key is chosen. What is the maximum number of messages that can be encrypted using the same key? The maximum ...

I am looking at an AES-CTR implementation (WebCrypto) and it takes an initialization parameter count which is an array of 16 bytes. It then asks you to specify <...

There are situations where a single connection (or file) may require additional throughput available. While network bandwidth and CPU cores are available, they cannot be utilised. (Aside from means ...

From what I understand, CTR works by taking a counter, concatenating it with a nonce, and encrypting the result, which gets XORed to the ciphertext. For a 128-bit block cipher (ie. AES), my ...

Reading https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Counter_(CTR) it looks like CTR (and some other modes) encrypt the nonce (plus count, for CTR) rather than the plaintext. The ...

I have an (offline) shared secret key (symmetric) which is used to encrypt/decrypt data. Now this data belongs to a specific user which is known on the backend and frontend. My idea was to use the ...

Let ssuppose that we are using AES in CTR mode to encrypt a number of blocks ($x$ bytes each). How is the current used IV (nonce+ctr) synchronized among both communicating entities? I suppose that the ...