Linked Questions

19 votes
4 answers

Is SHA-256 secure as a CTR block cipher?

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. <...
Jordan's user avatar
  • 575
4 votes
1 answer

Is regular CTR mode vulnerable to any attacks?

Regular plain CTR mode, is it vulnerable to any attack? I plan to write a program to encrypt a drive with ctr mode. Would this be wise? Would AES be better? When I look at this diagram, it looks ...
tuang's user avatar
  • 43
17 votes
1 answer

Bit Flipping Attack on CBC Mode

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 ...
CXB's user avatar
  • 311
12 votes
3 answers

Using a Non-Random IV with modes other than CBC

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, ...
Rook's user avatar
  • 1,486
3 votes
3 answers

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 ...
moyu's user avatar
  • 73
13 votes
1 answer

What are the rules for using AES-GCM correctly?

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 ...
ams's user avatar
  • 611
2 votes
2 answers

What is the difference between pseudorandom permutation/pseudorandom function/block cipher?

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?
Mark's user avatar
  • 21
1 vote
2 answers

How insecure would a cipher based on iterative hashing be?

I was just wondering how the following construction could be insecure. I can tell that known-plain attacks are possible, but I'm not sure about anything else. Let the user pick a password and hash it ...
Li Gang's user avatar
  • 19
2 votes
2 answers

Does keeping IV secret increase security of CTR mode?

Let's suppose I encrypt something with CTR mode and keep the key and IV secret. Does keeping the IV secret together with the key increase strength of encryption?
phantomcraft's user avatar
5 votes
1 answer

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 ...
Contaso's user avatar
  • 53
3 votes
2 answers

Proper use of AES CTR

I've read that AES CTR is only safe if used properly. Therefore, I want to be sure that I use it properly. The initial vector (IV) can only be used once, it doesn't have to be random. Is it secure to ...
SOSO30's user avatar
  • 33
0 votes
2 answers

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 ...
Kind Contributor's user avatar
1 vote
2 answers

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 ...
user avatar
3 votes
1 answer

What is the maximum number of messages that can be encrypted using the same key for CTR mode?

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 ...
geektobe's user avatar
2 votes
3 answers

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 ...
Baldovín Cadena Mejía's user avatar

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