Linked Questions

2
votes
3answers
87 views

What does counter mean in Counter (CTR) Mode? Is it the same as nonce?

As asked above, what does "counter" mean exactly? Is it the same as nonce? Also, the book Network Security Essentials (6ed.) from William Stallings states, "Typically the counter is ...
0
votes
0answers
16 views

Use HMAC for every block encryption operation [duplicate]

Is it possible to use HMAC while performing encryption of blocks? I think that the main problem with the approach would be to get the same output size as the block, from the HMAC function. Also, the ...
1
vote
2answers
239 views

Why is possible to encrypt multiple messages within the same stream in AES

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 ...
2
votes
1answer
141 views

Do some Block Cipher Modes encrypt the nonce and then XOR it with the data?

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 ...
0
votes
0answers
37 views

Equivalent keys in Hash Functions

Let's suppose I want to use a (keyed) hash function as a stream cipher, I provide a key and a message to be hashed as a counter (like a nonce), and so, XOR each hashed output block on the plaintext. ...
0
votes
0answers
40 views

Hashing function as a cipher in CTR mode [duplicate]

Can we use hashing function in CTR mode as a cipher? And our key could be a random initialization vector. Are there any practical problems with that idea, that we don't do this?
2
votes
2answers
207 views

Secure AES IV with static salt

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 ...
0
votes
2answers
119 views

Encryption algorithm multiple threads/cores for higher throughput

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 ...
2
votes
2answers
133 views

How much data can we encrypt using AES 256 before changing the key?

Although this question has been answered in this link (After How Much Data Encryption (AES-256) we should change key?), I am not satisfied with the answers because the Recommendation for Block Cipher ...
1
vote
1answer
140 views

CTR block generation

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 ...
1
vote
1answer
92 views

Is Paillier a stream or block encryption

Does Paillier follow a stream encryption or block encryption technique. If it’s a block encryption then what is the size of the block in bits or bytes.
0
votes
2answers
641 views

Is CTR more secure than CBC?

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 ...
2
votes
2answers
176 views

With AES-CTR does the block input need to be implemented as nonce || counter?

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 <...
1
vote
1answer
214 views

AES CTR - Counter Management

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 ...
5
votes
1answer
234 views

Stream Cipher Key Stream from Successive Hashes

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 ...

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